DRUG INTERACTIONS
Abacavir; Dolutegravir; Lamivudine: (Contraindicated) Concurrent use of dolutegravir with dofetilide is contraindicated due of the potential for serious and life-threatening adverse events, such as QT prolongation and torsade de pointes (TdP). Dolutegravir inhibits the renal organic cation transporter OCT2, dofetilide is eliminated via this transporter. If coadministered, the plasma concentration of dofetilide may increase. (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Abacavir; Lamivudine, 3TC: (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Abacavir; Lamivudine, 3TC; Zidovudine, ZDV: (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Abarelix: (Contraindicated) Since abarelix can cause QT prolongation, abarelix should be used cautiously, if at all, with other drugs that are associated with QT prolongation, including dofetilide.
Adefovir: (Moderate) Adefovir is eliminated renally by a combination of glomerular filtration and active tubular secretion; coadministration of adefovir dipivoxil with drugs that reduce renal function or compete for active tubular secretion, such as dofetilide, may decrease adefovir elimination by competing for common renal tubular transport systems, therefore increasing serum concentrations of either adefovir and/or these coadministered drugs.
Alfuzosin: (Major) Coadministration of dofetilide and alfuzosin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Alfuzosin may prolong the QT interval in a dose-dependent manner.
Aliskiren; Amlodipine: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Alogliptin; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Amiloride: (Major) Drugs that are actively secreted via cationic tubular secretion, such as amiloride, should be co-administered with caution with dofetilide since they could increase dofetilide plasma concentrations via potential competition for renal cationic secretion. Increased dofetilide plasma concentrations may be associated with proarrhythmias.
Amiloride; Hydrochlorothiazide, HCTZ: (Major) Drugs that are actively secreted via cationic tubular secretion, such as amiloride, should be co-administered with caution with dofetilide since they could increase dofetilide plasma concentrations via potential competition for renal cationic secretion. Increased dofetilide plasma concentrations may be associated with proarrhythmias.
Amiodarone: (Major) Coadministration of dofetilide and amiodarone is not recommended as concurrent use may increase the risk of QT prolongation. Class III antiarrhythmic agents, such as amiodarone, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Both dofetilide and amiodarone are associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Although the frequency of TdP is less with amiodarone than with other Class III agents, amiodarone is still associated with a risk of TdP. Due to the extremely long half-life of amiodarone, a drug interaction is possible for days to weeks after discontinuation of amiodarone. In clinical trials, dofetilide was administered to patients previously treated with oral amiodarone only if serum amiodarone concentrations were below 0.3 mg/L or amiodarone had been withdrawn for at least three months.
Amisulpride: (Major) Coadministration of dofetilide and amisulpride is not recommended as concurrent use may increase the risk of QT prolongation. Monitor ECGs for QT prolongation if concomitant use is unavoidable. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Amisulpride causes dose- and concentration- dependent QT prolongation.
Amlodipine: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Amlodipine; Atorvastatin: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Amlodipine; Benazepril: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Amlodipine; Celecoxib: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Amlodipine; Olmesartan: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Amlodipine; Valsartan: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Amlodipine; Valsartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Amoxicillin; Clarithromycin; Omeprazole: (Major) Coadministration of dofetilide and clarithromycin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Clarithromycin is associated with an established risk for QT prolongation and TdP.
Amphotericin B cholesteryl sulfate complex (ABCD): (Major) Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs, such as amphotericin B, increasing the potential for dofetilide-induced torsade de pointes. Potassium levels should be within the normal range prior and during administration of dofetilide.
Amphotericin B lipid complex (ABLC): (Major) Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs, such as amphotericin B, increasing the potential for dofetilide-induced torsade de pointes. Potassium levels should be within the normal range prior and during administration of dofetilide.
Amphotericin B liposomal (LAmB): (Major) Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs, such as amphotericin B, increasing the potential for dofetilide-induced torsade de pointes. Potassium levels should be within the normal range prior and during administration of dofetilide.
Amphotericin B: (Major) Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs, such as amphotericin B, increasing the potential for dofetilide-induced torsade de pointes. Potassium levels should be within the normal range prior and during administration of dofetilide.
Amprenavir: (Contraindicated) Amprenavir may inhibit the metabolism of medications that are metabolized via CYP3A4. Although drug interaction studies have not been conducted, the serum concentrations of dofetilide may be increased with concomitant administration of amprenavir.
Anagrelide: (Major) Coadministration of dofetilide and anagrelide is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. TdP and ventricular tachycardia have been reported during postmarketing use of anagrelide.
Apomorphine: (Major) Coadministration of dofetilide and apomorphine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Dose-related QTc prolongation is associated with therapeutic apomorphine exposure.
Aprepitant, Fosaprepitant: (Major) Use caution if dofetilide and aprepitant, fosaprepitant are used concurrently and monitor for an increase in dofetilide-related adverse effects, including QT prolongation and torsade de pointes (TdP), for several days after administration of a multi-day aprepitant regimen. In vitro, dofetilide is a CYP3A4 substrate, although it has low affinity for this isoenzyme. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer and may increase plasma concentrations of dofetilide. Erythromycin, a potent CYP3A4 inhibitor, significantly increases dofetilide plasma concentrations. The AUC of a single dose of another CYP3A4 substrate, midazolam, increased by 2.3-fold on day 1 and by 3.3-fold on day 5 when coadministered with a 5-day oral aprepitant regimen. After a 3-day oral aprepitant regimen, the AUC of midazolam (given on days 1, 4, 8, and 15) increased by 25% on day 4, and then decreased by 19% and 4% on days 8 and 15, respectively. As a single 125 mg or 40 mg oral dose, the inhibitory effect of aprepitant on CYP3A4 is weak, with the AUC of midazolam increased by 1.5-fold and 1.2-fold, respectively. After administration, fosaprepitant is rapidly converted to aprepitant and shares many of the same drug interactions. However, as a single 150 mg intravenous dose, fosaprepitant only weakly inhibits CYP3A4 for a duration of 2 days; there is no evidence of CYP3A4 induction. Fosaprepitant 150 mg IV as a single dose increased the AUC of midazolam (given on days 1 and 4) by approximately 1.8-fold on day 1; there was no effect on day 4. Less than a 2-fold increase in the midazolam AUC is not considered clinically important.
Aripiprazole: (Major) Coadministration of dofetilide and aripiprazole is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation has occurred during therapeutic use of aripiprazole and following overdose.
Arsenic Trioxide: (Major) Avoid concomitant use of arsenic trioxide and dofetilide due to the potential for additive QT prolongation; discontinue or select an alternative drug that does not prolong the QT interval prior to starting arsenic trioxide therapy. If concomitant drug use is unavoidable, frequently monitor electrocardiograms. Torsade de pointes (TdP), QT interval prolongation, and complete atrioventricular block have been reported with arsenic trioxide use. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Artemether; Lumefantrine: (Major) Avoid coadministration of artemether; lumefantrine with dofetilide due to the potential for additive QT prolongation. Consider ECG monitoring if dofetilide must be used with or after artemether; lumefantrine treatment. Artemether; lumefantrine is associated with prolongation of the QT interval. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Articaine; Epinephrine: (Moderate) Monitor patients who receive epinephrine while concomitantly taking antiarrhythmics for the development of arrhythmias. Epinephrine may produce ventricular arrhythmias in patients who are on drugs that may sensitize the heart to arrhythmias.
Asciminib: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with asciminib is necessary as concurrent use may increase dofetilide exposure. Asciminib is a weak CYP3A inhibitor. Dofetilide is a minor CYP3A substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A inhibitors may increase the risk of arrhythmia (torsade de pointes).
Asenapine: (Major) Coadministration of dofetilide and asenapine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Asenapine has been associated with QT prolongation.
Atazanavir: (Major) Coadministration of CYP3A4 inhibitors, such as atazanavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Atazanavir; Cobicistat: (Major) Coadministration of CYP3A4 inhibitors, such as atazanavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Atomoxetine: (Major) Coadministration of dofetilide and atomoxetine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation has occurred during therapeutic use of atomoxetine and following overdose.
Avacopan: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with avacopan is necessary as concurrent use may increase dofetilide exposure. Avacopan is a weak CYP3A inhibitor. Dofetilide is a minor CYP3A substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A inhibitors may increase the risk of arrhythmia (torsade de pointes).
Azelastine; Fluticasone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Azithromycin: (Major) Avoid coadministration of azithromycin with dofetilide due to the increased risk of QT prolongation. If use together is necessary, obtain an ECG at baseline to assess initial QT interval and determine frequency of subsequent ECG monitoring, avoid any non-essential QT prolonging drugs, and correct electrolyte imbalances. QT prolongation and torsade de pointes (TdP) have been spontaneously reported during azithromycin postmarketing surveillance. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Beclomethasone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Bedaquiline: (Major) Coadministration of dofetilide and bedaquiline is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor ECGs during treatment. Discontinue bedaquiline if evidence of serious ventricular arrhythmia or QTcF interval greater than 500 milliseconds. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Bedaquiline also prolongs the QT interval.
Belumosudil: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with belumosudil is necessary as concurrent use may increase dofetilide exposure. Belumosudil is a weak CYP3A inhibitor. Dofetilide is a minor CYP3A substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A inhibitors may increase the risk of arrhythmia (torsade de pointes).
Berotralstat: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with berotralstat is necessary as concurrent use may increase dofetilide exposure. Dofetilide is a minor CYP3A4 substrate and berotralstat is a moderate CYP3A4 inhibitor; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Betamethasone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Bicalutamide: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with bicalutamide is necessary as concurrent use may increase dofetilide exposure. bicalutamide is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Contraindicated) Concomitant use of bictegravir and dofetilide is contraindicated due to the potential for increased dofetilide plasma concentrations and risk of serious and/or life-threatening events. Dofetilide is a substrate of OCT2 and MATE1; bictegravir is an inhibitor of these drug transporters. (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Bismuth Subcitrate Potassium; Metronidazole; Tetracycline: (Major) Concomitant use of metronidazole and dofetilide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary.
Bismuth Subsalicylate; Metronidazole; Tetracycline: (Major) Concomitant use of metronidazole and dofetilide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary.
Bosentan: (Moderate) Theoretically, bosentan can induce the hepatic metabolism of dofetilide via CYP3A4 isoenzymes. The clinical significance of this interaction is unknown.
Bretylium: (Major) Withdraw bretylium at least 3 half-lives before starting dofetilide therapy.
Budesonide: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Budesonide; Formoterol: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Budesonide; Glycopyrrolate; Formoterol: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Bupivacaine; Epinephrine: (Moderate) Monitor patients who receive epinephrine while concomitantly taking antiarrhythmics for the development of arrhythmias. Epinephrine may produce ventricular arrhythmias in patients who are on drugs that may sensitize the heart to arrhythmias.
Bupivacaine; Lidocaine: (Contraindicated) Concurrent exposure of systemic lidocaine with dofetilide could increase the risk of dofetilide-induced proarrhythmias. Before switching from lidocaine to dofetilide therapy, lidocaine generally should be withheld for at least three half-lives prior to initiating dofetilide. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP).
Buprenorphine: (Major) Coadministration of dofetilide and buprenorphine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Buprenorphine has been associated with QT prolongation and has a possible risk of TdP.
Buprenorphine; Naloxone: (Major) Coadministration of dofetilide and buprenorphine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Buprenorphine has been associated with QT prolongation and has a possible risk of TdP.
Cabotegravir; Rilpivirine: (Major) Coadministration of dofetilide and rilpivirine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Supratherapeutic doses of rilpivirine (75 to 300 mg/day) have caused QT prolongation.
Canagliflozin; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Cardiac glycosides: (Major) Dofetilide does not affect the pharmacokinetics of digoxin; however, the concomitant administration of digoxin with dofetilide is associated with a higher occurrence of torsade de pointes.
Ceritinib: (Major) Avoid coadministration of ceritinib with dofetilide due to the risk of QT prolongation. If concomitant use is unavoidable, periodically monitor ECGs and electrolytes; an interruption of ceritinib therapy, dose reduction, or discontinuation of therapy may be necessary if QT prolongation occurs. Dofetilide is a CYP3A4 substrate that is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Ceritinib is a strong CYP3A4 inhibitor that is also associated with concentration-dependent QT prolongation.
Chloroquine: (Major) Avoid coadministration of chloroquine with dofetilide due to the increased risk of QT prolongation. If use together is necessary, obtain an ECG at baseline to assess initial QT interval and determine frequency of subsequent ECG monitoring, avoid any non-essential QT prolonging drugs, and correct electrolyte imbalances. Chloroquine is associated with an increased risk of QT prolongation and torsade de pointes (TdP); the risk of QT prolongation is increased with higher chloroquine doses. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Chlorpromazine: (Major) Coadministration of dofetilide and chlorpromazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Chlorpromazine, a phenothiazine, is associated with an established risk of QT prolongation and TdP.
Ciclesonide: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Cimetidine: (Contraindicated) Cimetidine is an inhibitor of renal cationic tubular secretion and is contraindicated with dofetilide due to the potential for increased plasma dofetilide concentrations and associated proarrhythmias. Cimetidine (400 mg PO twice daily) coadministered with dofetilide (500 mcg PO twice daily) for 7 days increased dofetilide plasma levels by 58%. Cimetidine, at over-the-counter doses of 100 mg PO twice daily, results in a 13% increase in dofetilide plasma concentrations following a single 500 mcg oral dose. Omeprazole, ranitidine, or antacids (aluminum and magnesium hydroxides) may be used as anti-ulcer therapy alternatives to cimetidine; these agents did not alter dofetilide pharmacokinetics.
Ciprofloxacin: (Major) Coadministration of dofetilide and ciprofloxacin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Rare cases of QT prolongation and TdP have been reported with ciprofloxacin during postmarketing surveillance.
Cisapride: (Contraindicated) Coadministration of cisapride with dofetilide is contraindicated due to the potential for QT prolongation and torsade de pointes (TdP). QT prolongation and ventricular arrhythmias, including TdP and death, have been reported with cisapride. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Citalopram: (Major) Coadministration of dofetilide and citalopram is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor ECG. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Citalopram causes dose-dependent QT interval prolongation.
Clarithromycin: (Major) Coadministration of dofetilide and clarithromycin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Clarithromycin is associated with an established risk for QT prolongation and TdP.
Clofazimine: (Major) Coadministration of dofetilide and clofazimine is not recommended as concurrent use may increase the risk of QT prolongation. Monitor ECGs for QT prolongation if concomitant use is unavoidable. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation and TdP have been reported in patients receiving clofazimine in combination with QT prolonging medications.
Clozapine: (Major) Coadministration of dofetilide and clozapine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Treatment with clozapine has been associated with QT prolongation, TdP, cardiac arrest, and sudden death.
Codeine; Phenylephrine; Promethazine: (Major) Coadministration of dofetilide and promethazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Promethazine, a phenothiazine, is associated with a possible risk for QT prolongation.
Codeine; Promethazine: (Major) Coadministration of dofetilide and promethazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Promethazine, a phenothiazine, is associated with a possible risk for QT prolongation.
Conivaptan: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with conivaptan is necessary as concurrent use may increase dofetilide exposure. Conivaptan is a moderate CYP3A inhibitor. Dofetilide is a minor CYP3A substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc prolongation, concomitant administration of CYP3A inhibitors may increase the risk of arrhythmias such as torsade de pointes.
Corticosteroids: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Cortisone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Crizotinib: (Major) Avoid coadministration of crizotinib with dofetilide due to the risk of QT prolongation. If concomitant use is unavoidable, monitor ECGs for QT prolongation and monitor electrolytes. An interruption of therapy, dose reduction, or discontinuation of therapy may be necessary for crizotinib if QT prolongation occurs. Crizotinib can cause concentration-dependent QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Danazol: (Major) Danazol could significantly inhibit the CYP3A4 metabolism of dofetilide. The resultant increase in serum dofetilide concentrations could increase the risk of torsade de pointes.
Dapagliflozin; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Darunavir: (Major) Coadministration of CYP3A4 inhibitors, such as darunavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Darunavir; Cobicistat: (Major) Coadministration of CYP3A4 inhibitors, such as darunavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Major) Coadministration of CYP3A4 inhibitors, such as darunavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias. (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Concomitant use of dofetilide and ritonavir may increase the risk of QT prolongation and torsade de pointes (TdP) due to increased dofetilide exposure. Dofetilide is metabolized to a small degree by CYP3A4; ritonavir is a potent inhibitor of CYP3A4.
Dasatinib: (Major) Coadministration of dofetilide and dasatinib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). In vitro studies have shown that dasatinib has the potential to prolong the QT interval.
Deflazacort: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Degarelix: (Major) Coadministration of dofetilide and degarelix is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Androgen deprivation therapy (i.e., degarelix) may prolong the QT/QTc interval.
Delavirdine: (Contraindicated) Avoid concurrent use of dofetilide with delavirdine. Delavirdine may theoretically inhibit the CYP3A4 metabolism of dofetilide, resulting in elevated dofetilide plasma concentrations. Dofetilide plasma concentrations are correlated with the risk of drug-induced proarrhythmias.
Desflurane: (Major) Coadministration of dofetilide and halogenated anesthetics is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Halogenated anesthetics can prolong the QT interval.
Deutetrabenazine: (Major) Coadministration of dofetilide and deutetrabenazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Deutetrabenazine may prolong the QT interval, but the degree of QT prolongation is not clinically significant when deutetrabenazine is administered within the recommended dosage range.
Dexamethasone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Dextromethorphan; Quinidine: (Contraindicated) Coadministration of dofetilide and quinidine is contraindicated as concurrent use may increase the risk QT prolongation and torsades de pointes (TdP). Class I antiarrhythmic agents, such as quinidine, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Quinidine administration is associated with QT prolongation and TdP.
Diltiazem: (Major) Diltiazem should be used with caution with dofetilide since it may increase dofetilide plasma concentrations via inhibition of CYP3A4 metabolism. This interaction may increase the potential for dofetilide-induced proarrhythmias.
Disopyramide: (Major) Coadministration of dofetilide and disopyramide is not recommended as concurrent use may increase the risk of QT prolongation. Class I antiarrhythmic agents, such as disopyramide, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Disopyramide administration is associated with QT prolongation and TdP.
Dolasetron: (Major) Coadministration of dofetilide and dolasetron is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Dolasetron has been associated with a dose-dependent prolongation in the QT, PR, and QRS intervals on an electrocardiogram.
Dolutegravir: (Contraindicated) Concurrent use of dolutegravir with dofetilide is contraindicated due of the potential for serious and life-threatening adverse events, such as QT prolongation and torsade de pointes (TdP). Dolutegravir inhibits the renal organic cation transporter OCT2, dofetilide is eliminated via this transporter. If coadministered, the plasma concentration of dofetilide may increase.
Dolutegravir; Lamivudine: (Contraindicated) Concurrent use of dolutegravir with dofetilide is contraindicated due of the potential for serious and life-threatening adverse events, such as QT prolongation and torsade de pointes (TdP). Dolutegravir inhibits the renal organic cation transporter OCT2, dofetilide is eliminated via this transporter. If coadministered, the plasma concentration of dofetilide may increase. (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Dolutegravir; Rilpivirine: (Contraindicated) Concurrent use of dolutegravir with dofetilide is contraindicated due of the potential for serious and life-threatening adverse events, such as QT prolongation and torsade de pointes (TdP). Dolutegravir inhibits the renal organic cation transporter OCT2, dofetilide is eliminated via this transporter. If coadministered, the plasma concentration of dofetilide may increase. (Major) Coadministration of dofetilide and rilpivirine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Supratherapeutic doses of rilpivirine (75 to 300 mg/day) have caused QT prolongation.
Donepezil: (Major) Coadministration of dofetilide and donepezil is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Case reports indicate that QT prolongation and TdP can occur during donepezil therapy.
Donepezil; Memantine: (Major) Coadministration of dofetilide and donepezil is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Case reports indicate that QT prolongation and TdP can occur during donepezil therapy. (Major) Drugs that are actively secreted via cationic secretion (e.g., memantine) should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion. Competition for renal elimination may increase plasma concentrations of dofetilide and increase the risk of pro-arrhythmias.
Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended. (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Dronedarone: (Contraindicated) Concurrent use of dronedarone and dofetilide is contraindicated. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP). Dronedarone administration is associated with a dose-related increase in the QTc interval. The increase in QTc is approximately 10 milliseconds at doses of 400 mg twice daily (the FDA-approved dose) and up to 25 milliseconds at doses of 1600 mg twice daily. Although there are no studies examining the effects of dronedarone in patients receiving other QT prolonging drugs, coadministration of such drugs may result in additive QT prolongation. The concomitant use of dronedarone with other drugs that prolong the QTc may induce TdP and is contraindicated.
Droperidol: (Major) Coadministration of dofetilide and droperidol is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, use extreme caution; initiate droperidol at a low dose and increase the dose as needed to achieve the desired effect. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Droperidol administration is associated with an established risk for QT prolongation and TdP. Some cases have occurred in patients with no known risk factors for QT prolongation and some cases have been fatal.
Duvelisib: (Major) Monitor for an increase in dofetilide-related adverse effects, including QT prolongation and torsade de pointes (TdP), if coadministered with duvelisib. Coadministration may increase the exposure of dofetilide. Dofetilide is a CYP3A substrate; duvelisib is a moderate CYP3A inhibitor.
Efavirenz: (Major) Coadministration of dofetilide and efavirenz is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QTc prolongation has been observed with the use of efavirenz.
Efavirenz; Emtricitabine; Tenofovir: (Major) Coadministration of dofetilide and efavirenz is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QTc prolongation has been observed with the use of efavirenz. (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended. (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Coadministration of dofetilide and efavirenz is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QTc prolongation has been observed with the use of efavirenz. (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended. (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Eliglustat: (Major) Coadministration of dofetilide and eliglustat is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Eliglustat is predicted to cause PR, QRS, and/or QT prolongation at significantly elevated plasma concentrations.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended. (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Empagliflozin; Linagliptin; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Empagliflozin; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Emtricitabine: (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Major) Coadministration of dofetilide and rilpivirine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Supratherapeutic doses of rilpivirine (75 to 300 mg/day) have caused QT prolongation. (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate: (Major) Coadministration of dofetilide and rilpivirine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Supratherapeutic doses of rilpivirine (75 to 300 mg/day) have caused QT prolongation. (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended. (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Emtricitabine; Tenofovir alafenamide: (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Emtricitabine; Tenofovir disoproxil fumarate: (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended. (Moderate) Use caution when administering dofetilide concurrently with emtricitabine as both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia.
Encainide: (Contraindicated) Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP). Before switching from another antiarrhythmic drug to dofetilide therapy, antiarrhythmics generally should be withheld for at least three half-lives prior to initiating dofetilide. According to the manufacturer, Class I (disopyramide, encainide, flecainide, lidocaine, mexiletine, moricizine, procainamide, propafenone, quinidine, and tocainide) and Class III (e.g., amiodarone, bretylium, ibutilide, and sotalol) antiarrhythmic agents are associated with QT prolongation and ventricular arrhythmias and concurrent exposure with dofetilide could increase the risk of dofetilide-induced proarrhythmias.
Encorafenib: (Major) Avoid coadministration of encorafenib and dofetilide due to QT prolongation. If concurrent use cannot be avoided, monitor ECGs for QT prolongation and monitor electrolytes; correct hypokalemia and hypomagnesemia prior to treatment. Encorafenib has been associated with dose-dependent QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Enflurane: (Major) Coadministration of dofetilide and halogenated anesthetics is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Halogenated anesthetics can prolong the QT interval.
Entecavir: (Major) In the manufacturers package label for dofetilide, administration of drugs that are excreted via renal tubular secretion should be used very cautiously, if at all, with dofetilide. Entecavir is also excreted via renal tubular excretion.
Entrectinib: (Major) Avoid coadministration of entrectinib with dofetilide due to the risk of QT prolongation. Entrectinib has been associated with QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Epinephrine: (Moderate) Monitor patients who receive epinephrine while concomitantly taking antiarrhythmics for the development of arrhythmias. Epinephrine may produce ventricular arrhythmias in patients who are on drugs that may sensitize the heart to arrhythmias.
Erdafitinib: (Contraindicated) Coadministration of dofetilide with erdafitinib is contraindicated due to the risk of increased dofetilide exposure which may be associated with QT prolongation. Dofetilide is eliminated in the kidney by cationic secretion. Erdafitinib is an inhibitor of the renal uptake transporter organic cation transporter 2 (OCT2).
Eribulin: (Major) Coadministration of dofetilide and eribulin is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor ECG. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Eribulin has been associated with QT prolongation.
Ertugliflozin; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Erythromycin: (Major) Coadministration of dofetilide and erythromycin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Erythromycin is associated with QT prolongation and TdP. In addition, erythromycin may theoretically increase plasma concentrations of dofetilide via inhibition of CYP3A4. Higher antiarrhythmic plasma concentrations increase the potential risk of QT prolongation, TdP, or other proarrhythmias.
Erythromycin; Sulfisoxazole: (Major) Coadministration of dofetilide and erythromycin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Erythromycin is associated with QT prolongation and TdP. In addition, erythromycin may theoretically increase plasma concentrations of dofetilide via inhibition of CYP3A4. Higher antiarrhythmic plasma concentrations increase the potential risk of QT prolongation, TdP, or other proarrhythmias.
Escitalopram: (Major) Coadministration of dofetilide and escitalopram is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Escitalopram has been associated with a risk of QT prolongation and TdP.
Everolimus: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with everolimus is necessary. Everolimus is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Ezogabine: (Major) Coadministration of dofetilide and ezogabine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Ezogabine has been associated with QT prolongation.
Fedratinib: (Contraindicated) Concomitant use of dofetilide and fedratinib is contraindicated. This combination may increase dofetilide exposure and the risk of dofetilide-related adverse effects including drug-induced QT prolongation and torsade de pointes (TdP). Dofetilide is an OCT2 and CYP3A substrate; fedratinib is an OCT2 and moderate CYP3A inhibitor.
Fingolimod: (Contraindicated) Fingolimod is contraindicated in patients requiring treatment with dofetilide, a Class III antiarrhythmic. Fingolimod treatment results in decreased heart rate and may prolong the QT interval. Dofetilide is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Flecainide: (Major) Coadministration of dofetilide and flecainide is not recommended as concurrent use may increase the risk of QT prolongation. Class I antiarrhythmic agents, such as flecainide, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Flecainide is a Class IC antiarrhythmic associated with a possible risk for QT prolongation and/or TdP; flecainide increases the QT interval, but largely due to prolongation of the QRS interval. Although causality for TdP has not been established for flecainide, patients receiving concurrent drugs that have the potential for QT prolongation may have an increased risk of developing proarrhythmias.
Fluconazole: (Contraindicated) Coadministration of dofetilide and fluconazole is contraindicated as concurrent use may increase the risk of QT prolongation and torsade de pointes (TdP). Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Fluconazole has been associated with QT prolongation and rare cases of TdP. Additionally, fluconazole is also an inhibitor of CYP3A4, which could increase dofetilide exposure, further increasing the risk of cardiac events.
Fludrocortisone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Flunisolide: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Fluoxetine: (Major) Coadministration of dofetilide and fluoxetine is not recommended as concurrent use may increase the risk of QT prolongation and torsade de pointes (TdP). QT prolongation and TdP have been reported in patients treated with fluoxetine. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. The use of dofetilide with other drugs that prolong the QT interval has not been studied and is not recommended.
Fluphenazine: (Minor) Fluphenazine is associated with a possible risk for QT prolongation. Theoretically, fluphenazine may increase the risk of QT prolongation if coadministered with other drugs that have a risk of QT prolongation, such as dofetilide.
Fluticasone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Fluticasone; Salmeterol: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Fluticasone; Umeclidinium; Vilanterol: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Fluticasone; Vilanterol: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Fluvoxamine: (Major) Coadministration of dofetilide and fluvoxamine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation and TdP have also been reported during fluvoxamine postmarketing use. Additionally, fluvoxamine is also an inhibitor of CYP3A4, which could increase dofetilide exposure, further increasing the risk of cardiac events.
Formoterol; Mometasone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Fosamprenavir: (Major) Coadministration of CYP3A4 inhibitors, such as fosamprenavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Foscarnet: (Major) Coadministration of dofetilide and foscarnet is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Both QT prolongation and TdP have been reported during postmarketing use of foscarnet.
Fostamatinib: (Moderate) Monitor for dofetilide toxicities that may require dofetilide dose reduction if given concurrently with fostamatinib. Concomitant use of fostamatinib with a CYP3A4 substrate may increase the concentration of the CYP3A4 substrate. The active metabolite of fostamatinib, R406, is a CYP3A4 inhibitor; dofetilide is a substrate for CYP3A4. Coadministration of fostamatinib with a sensitive CYP3A4 substrate increased the substrate AUC by 64% and Cmax by 113%.
Fostemsavir: (Major) Coadministration of dofetilide and fostemsavir is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Supratherapeutic doses of fostemsavir (2,400 mg twice daily, 4 times the recommended daily dose) have been shown to cause QT prolongation. Fostemsavir causes dose-dependent QT prolongation.
Gemifloxacin: (Major) Coadministration of dofetilide and gemifloxacin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Gemifloxacin may prolong the QT interval in some patients. The maximal change in the QTc interval occurs approximately 5 to 10 hours following oral administration of gemifloxacin. The likelihood of QTc prolongation may increase with increasing dose of the drug; therefore, the recommended dose should not be exceeded especially in patients with renal or hepatic impairment where the Cmax and AUC are slightly higher.
Gemtuzumab Ozogamicin: (Major) Coadministration of dofetilide and gemtuzumab is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, obtain an ECG and serum electrolytes prior to the start of gemtuzumab and as needed during treatment. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Although QT interval prolongation has not been reported with gemtuzumab, it has been reported with other drugs that contain calicheamicin.
Gilteritinib: (Major) Coadministration of dofetilide and gilteritinib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Gilteritinib has been associated with QT prolongation.
Glasdegib: (Major) Avoid coadministration of glasdegib with dofetilide due to the potential for additive QT prolongation. If coadministration cannot be avoided, monitor patients for increased risk of QT prolongation with increased frequency of ECG monitoring. Glasdegib therapy may result in QT prolongation and ventricular arrhythmias including ventricular fibrillation and ventricular tachycardia. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Glipizide; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Glyburide; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Goserelin: (Major) Coadministration of dofetilide and goserelin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Androgen deprivation therapy (i.e., goserelin) may prolong the QT/QTc interval.
Granisetron: (Major) Coadministration of dofetilide and granisetron is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Granisetron has been associated with QT prolongation.
Grapefruit juice: (Major) Clinicians should be aware that food interactions with dofetilide are possible. Grapefruit juice inhibits the cytochrome P-450 3A4 isozyme in the gut wall. Grapefruit juice contains furanocoumarins that are metabolized by CYP3A4 to reactive intermediates. These intermediates form a covalent bond to the active site of the CYP3A4 enzyme, causing irreversible inactivation (mechanism-based inhibition). Consequently, CYP3A4 activity in the gut wall is inhibited until de novo synthesis returns the enzyme to its previous level. According to the manufacturer of dofetilide, caution should be used when coadministering with grapefruit juice. Elderly patients have the greatest possibility of ingesting grapefruit and interacting medications and are the most vulnerable to the adverse clinical consequences.
Halogenated Anesthetics: (Major) Coadministration of dofetilide and halogenated anesthetics is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Halogenated anesthetics can prolong the QT interval.
Haloperidol: (Major) Coadministration of dofetilide and haloperidol is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation and TdP have been observed during haloperidol treatment. Excessive doses (particularly in the overdose setting) or IV administration of haloperidol may be associated with a higher risk of QT prolongation.
Halothane: (Major) Coadministration of dofetilide and halogenated anesthetics is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Halogenated anesthetics can prolong the QT interval.
Histrelin: (Major) Coadministration of dofetilide and histrelin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Androgen deprivation therapy (i.e., histrelin) may prolong the QT/QTc interval.
Hydrocortisone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Hydroxychloroquine: (Major) Avoid coadministration of dofetilide and hydroxychloroquine due to the risk of increased QT prolongation. If use together is necessary, obtain an ECG at baseline to assess initial QT interval and determine frequency of subsequent ECG monitoring, avoid any non-essential QT prolonging drugs, and correct electrolyte imbalances. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Hydroxychloroquine also prolongs the QT interval.
Hydroxyzine: (Major) Coadministration of dofetilide and hydroxyzine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Postmarketing data indicate that hydroxyzine causes QT prolongation and TdP.
Ibutilide: (Major) Coadministration of dofetilide and ibutilide is not recommended as concurrent use may increase the risk of QT prolongation. Class III antiarrhythmic agents, such as ibutilide, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Ibutilide administration can cause QT prolongation and TdP; proarrhythmic events should be anticipated. The potential for proarrhythmic events with ibutilide increases with the coadministration of other drugs that prolong the QT interval.
Iloperidone: (Major) Coadministration of dofetilide and iloperidone is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Iloperidone has been associated with QT prolongation.
Imatinib: (Major) Imatinib could significantly inhibit the CYP3A4 metabolism of dofetilide. The resultant increase in serum dofetilide concentrations could increase the risk of torsade de pointes.
Indapamide: (Major) Indapamide may induce hypokalemia, increasing the potential for proarrhythmic effects (e.g., torsade de pointes) of dofetilide. Potassium levels should be within the normal range prior and during administration of these agents. In the absence of electrolyte imbalances, these agents can be used together safely.
Indinavir: (Major) Coadministration of CYP3A4 inhibitors, such as indinavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Inotuzumab Ozogamicin: (Major) Avoid coadministration of inotuzumab with dofetilide due to the potential for additive QT prolongation and torsade de pointes (TdP). If coadministration is unavoidable, obtain ECGs and electrolytes prior to the start of treatment and periodically during treatment. Inotuzumab has been associated with QT interval prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Isavuconazonium: (Contraindicated) Concurrent use of isavuconazonium with dofetilide is contraindicated due to the potential for increased dofetilide exposure resulting in serious and life-threatening adverse events, such as QT prolongation and torsade de pointes (TdP). Isavuconazonium inhibits the renal organic cation transporter OCT2, and dofetilide is eliminated via this transporter.
Isoflurane: (Major) Coadministration of dofetilide and halogenated anesthetics is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Halogenated anesthetics can prolong the QT interval.
Isoniazid, INH: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with isoniazid is necessary. Isoniazid is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with isoniazid is necessary. Isoniazid is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Isoniazid, INH; Rifampin: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with isoniazid is necessary. Isoniazid is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Istradefylline: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with istradefylline 40 mg daily is necessary. Istradefylline administered as 40 mg daily is a weak CYP3A4 inhibitor. There was no effect on drug exposure when istradefylline 20 mg daily was coadministered with a sensitive CYP3A4 substrate. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Itraconazole: (Contraindicated) Use of dofetilide during and for 2 weeks after discontinuation of itraconazole treatment is contraindicated due to the potential elevated dofetilide concentrations and QT prolongation. Serious cardiovascular events including EKG changes (i.e., QT prolongation), cardiac arrhythmias, including ventricular arrhythmias and torsade de pointes, cardiac arrest, and sudden death may occur when these drugs are administered together. Itraconazole is a strong CYP3A4 inhibitor that has been associated with QT prolongation. Dofetilide is a CYP3A4 substrate that is associated with QT prolongation and torsade de pointes (TdP).
Ivosidenib: (Major) Avoid coadministration of ivosidenib with dofetilide due to an increased risk of QT prolongation. If concomitant use is unavoidable, monitor ECGs for QTc prolongation and monitor electrolytes; correct any electrolyte abnormalities as clinically appropriate. An interruption of therapy and dose reduction of ivosidenib may be necessary if QT prolongation occurs. Prolongation of the QTc interval and ventricular arrhythmias have been reported in patients treated with ivosidenib. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Ketoconazole: (Contraindicated) Concurrent use of dofetilide with ketoconazole is contraindicated due to the risk of serious cardiovascular events, including dose-dependent QT prolongation. Ketoconazole co-administered with dofetilide for 7 days has been shown to increase dofetilide Cmax by 53% in males and 97% in females, and increase dofetilide AUC by 41% in males and 69% in females. This interaction is proposed to occur primarily by inhibition of cationic renal tubular secretion by ketoconazole. Dofetilide is a substrate of OCT2 and MATE1; ketoconazole is an inhibitor of these drug transporters. CYP3A4 inhibition by ketoconazole may also contribute.
Lacosamide: (Moderate) Use lacosamide with caution in patients taking concomitant medications that affect cardiac conduction, such as Class III antiarrhythmics, because of the risk of AV block, bradycardia, or ventricular tachyarrhythmia. If use together is necessary, obtain an ECG prior to lacosamide initiation and after treatment has been titrated to steady-state. In addition, monitor patients receiving lacosamide via the intravenous route closely.
Lamivudine, 3TC: (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Lamivudine, 3TC; Zidovudine, ZDV: (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended. (Moderate) Drugs that are actively secreted via cationic secretion, such as lamivudine, should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Lamotrigine: (Major) Coadministration of lamotrigine and dofetilide is not recommended. Coadministration may decrease dofetilide clearance, resulting in increased plasma concentrations and the potential for serious adverse events, including QT prolongation and cardiac arrhythmias. Lamotrigine is an inhibitor of renal tubular secretion via organic cationic transporter 2 (OCT2) proteins, and dofetilide is excreted via this route.
Lansoprazole; Amoxicillin; Clarithromycin: (Major) Coadministration of dofetilide and clarithromycin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Clarithromycin is associated with an established risk for QT prolongation and TdP.
Lapatinib: (Major) Coadministration of dofetilide and lapatinib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Lapatinib has been associated with concentration-dependent QT prolongation; ventricular arrhythmias and TdP have been reported in postmarketing experience with lapatinib.
Larotrectinib: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with larotrectinib is necessary. larotrectinib is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Lefamulin: (Major) Avoid coadministration of lefamulin with dofetilide as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, ECG monitoring is recommended during treatment. Lefamulin has a concentration dependent QTc prolongation effect. The pharmacodynamic interaction potential to prolong the QT interval of the electrocardiogram between lefamulin and other drugs that effect cardiac conduction is unknown. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Lenvatinib: (Major) Coadministration of dofetilide and lenvatinib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Prolongation of the QT interval has been reported with lenvatinib therapy.
Letermovir: (Moderate) A clinically relevant increase in the plasma concentration of dofetilide may occur if given with letermovir; monitor patient closely for dofetilide-related adverse events. In patients who are also receiving treatment with cyclosporine, the magnitude of this interaction may be amplified. Dofetilide is metabolized to a small degree by CYP3A4. Letermovir is a moderate CYP3A4 inhibitor; however, when given with cyclosporine, the combined effect on CYP3A4 substrates is similar to a strong CYP3A4 inhibitor.
Leuprolide: (Major) Coadministration of dofetilide and leuprolide is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Androgen deprivation therapy (i.e., leuprolide) may prolong the QT/QTc interval.
Leuprolide; Norethindrone: (Major) Coadministration of dofetilide and leuprolide is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Androgen deprivation therapy (i.e., leuprolide) may prolong the QT/QTc interval.
Levamlodipine: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Levofloxacin: (Major) Coadministration of dofetilide and levofloxacin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Levofloxacin has been associated with a risk of QT prolongation and TdP. Although extremely rare, TdP has been reported during postmarketing surveillance of levofloxacin.
Levoketoconazole: (Contraindicated) Concurrent use of dofetilide with ketoconazole is contraindicated due to the risk of serious cardiovascular events, including dose-dependent QT prolongation. Ketoconazole co-administered with dofetilide for 7 days has been shown to increase dofetilide Cmax by 53% in males and 97% in females, and increase dofetilide AUC by 41% in males and 69% in females. This interaction is proposed to occur primarily by inhibition of cationic renal tubular secretion by ketoconazole. Dofetilide is a substrate of OCT2 and MATE1; ketoconazole is an inhibitor of these drug transporters. CYP3A4 inhibition by ketoconazole may also contribute.
Lidocaine: (Contraindicated) Concurrent exposure of systemic lidocaine with dofetilide could increase the risk of dofetilide-induced proarrhythmias. Before switching from lidocaine to dofetilide therapy, lidocaine generally should be withheld for at least three half-lives prior to initiating dofetilide. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP).
Lidocaine; Epinephrine: (Contraindicated) Concurrent exposure of systemic lidocaine with dofetilide could increase the risk of dofetilide-induced proarrhythmias. Before switching from lidocaine to dofetilide therapy, lidocaine generally should be withheld for at least three half-lives prior to initiating dofetilide. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP). (Moderate) Monitor patients who receive epinephrine while concomitantly taking antiarrhythmics for the development of arrhythmias. Epinephrine may produce ventricular arrhythmias in patients who are on drugs that may sensitize the heart to arrhythmias.
Lidocaine; Prilocaine: (Contraindicated) Concurrent exposure of systemic lidocaine with dofetilide could increase the risk of dofetilide-induced proarrhythmias. Before switching from lidocaine to dofetilide therapy, lidocaine generally should be withheld for at least three half-lives prior to initiating dofetilide. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP).
Linagliptin; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Lithium: (Major) Coadministration of dofetilide and lithium is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Lithium has been associated with QT prolongation.
Lofexidine: (Major) Coadministration of dofetilide and lofexidine is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor ECG. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Lofexidine prolongs the QT interval.
Lonafarnib: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with lonafarnib is necessary as concurrent use may increase dofetilide exposure. Dofetilide is a minor CYP3A4 substrate and lonarfarnib is a strong CYP3A4 inhibitor; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmias (torsade de pointes).
Loop diuretics: (Major) Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs such as loop diuretics increasing the potential for dofetilide-induced torsade de pointes. Potassium levels should be within the normal range prior and during administration of dofetilide.
Loperamide: (Major) Coadministration of dofetilide and loperamide is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). At high doses, loperamide has been associated with serious cardiac toxicities, including syncope, ventricular tachycardia, QT prolongation, TdP, and cardiac arrest.
Loperamide; Simethicone: (Major) Coadministration of dofetilide and loperamide is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). At high doses, loperamide has been associated with serious cardiac toxicities, including syncope, ventricular tachycardia, QT prolongation, TdP, and cardiac arrest.
Lopinavir; Ritonavir: (Major) Avoid coadministration of lopinavir with dofetilide due to the potential for additive QT prolongation. If use together is necessary, obtain a baseline ECG to assess initial QT interval and determine frequency of subsequent ECG monitoring, avoid any non-essential QT prolonging drugs, and correct electrolyte imbalances. Lopinavir is associated with QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). (Moderate) Concomitant use of dofetilide and ritonavir may increase the risk of QT prolongation and torsade de pointes (TdP) due to increased dofetilide exposure. Dofetilide is metabolized to a small degree by CYP3A4; ritonavir is a potent inhibitor of CYP3A4.
Macimorelin: (Major) Avoid concurrent administration of macimorelin with drugs that prolong the QT interval, such as dofetilide. Use of these drugs together may increase the risk of developing torsade de pointes-type ventricular tachycardia. Sufficient washout time of drugs that are known to prolong the QT interval prior to administration of macimorelin is recommended. Treatment with macimorelin has been associated with an increase in the corrected QT (QTc) interval. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Maprotiline: (Major) Coadministration of dofetilide and maprotiline is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Maprotiline has been reported to prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). Cases of long QT syndrome and TdP tachycardia have been described with maprotiline use, but rarely occur when the drug is used alone in normal prescribed doses and in the absence of other known risk factors for QT prolongation. Limited data are available regarding the safety of maprotiline in combination with other QT-prolonging drugs.
Maribavir: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with maribavir is necessary as concurrent use may increase dofetilide exposure. Maribavir is a weak CYP3A inhibitor. Dofetilide is a minor CYP3A substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A inhibitors may increase the risk of arrhythmia (torsade de pointes).
Mefloquine: (Major) Coadministration of dofetilide and mefloquine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). There is evidence that the use of halofantrine after mefloquine causes a significant lengthening of the QTc interval. Mefloquine alone has not been reported to cause QT prolongation.
Megestrol: (Contraindicated) All inhibitors of renal cationic secretion, including megestrol, are contraindicated with dofetilide. In a population pharmacokinetic analysis of plasma dofetilide concentrations, the mean clearance of dofetilide was 15% lower in patients receiving inhibitors of tubular organic cation transport.
Memantine: (Major) Drugs that are actively secreted via cationic secretion (e.g., memantine) should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion. Competition for renal elimination may increase plasma concentrations of dofetilide and increase the risk of pro-arrhythmias.
Meperidine; Promethazine: (Major) Coadministration of dofetilide and promethazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Promethazine, a phenothiazine, is associated with a possible risk for QT prolongation.
Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Metformin; Repaglinide: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Metformin; Rosiglitazone: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Metformin; Saxagliptin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Metformin; Sitagliptin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Methadone: (Major) Coadministration of dofetilide and methadone is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Methadone is considered to be associated with an increased risk for QT prolongation and TdP, especially at higher doses (more than 200 mg/day but averaging approximately 400 mg/day in adult patients). Most cases involve patients being treated for pain with large, multiple daily doses of methadone, although cases have been reported in patients receiving doses commonly used for maintenance treatment of opioid addiction.
Methylprednisolone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Metronidazole: (Major) Concomitant use of metronidazole and dofetilide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary.
Mexiletine: (Contraindicated) Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP). Before switching from another antiarrhythmic drug to dofetilide therapy, antiarrhythmics generally should be withheld for at least three half-lives prior to initiating dofetilide. According to the manufacturer, Class I (disopyramide, encainide, flecainide, lidocaine, mexiletine, moricizine, procainamide, propafenone, quinidine, and tocainide) antiarrhythmic agents are associated with QT prolongation and ventricular arrhythmias and concurrent exposure with dofetilide could increase the risk of dofetilide-induced proarrhythmias.
Midostaurin: (Major) Coadministration of dofetilide and midostaurin is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, consider interval assessments of QT by EKG. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation was reported in patients who received midostaurin in clinical trials.
Mifepristone: (Major) Coadministration of dofetilide and mifepristone is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Mifepristone is associated with dose-related prolongation of the QT interval. Additionally, dofetilide is metabolized to a small extent by CYP3A4, and inhibitors of CYP3A4, such as mifepristone, could increase systemic dofetilide exposure, further increasing the risk for QT prolongation.
Mirtazapine: (Major) Coadministration of dofetilide and mirtazapine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Mirtazapine has been associated with dose-dependent prolongation of the QT interval. TdP has been reported postmarketing, primarily in overdose or in patients with other risk factors for QT prolongation.
Mobocertinib: (Major) Concomitant use of mobocertinib and dofetilide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary.
Mometasone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Moricizine: (Contraindicated) In general, combination therapy with Class IC and Class III antiarrhythmics has been reported to increase the risk of proarrhythmias. Before switching from moricizine to dofetilide therapy, moricizine generally should be withheld for at least three half-lives prior to initiating dofetilide. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP). Class I antiarrhythmic agents are contraindicated with dofetilide, and may increase the risk of dofetilide-induced proarrhythmias.
Moxifloxacin: (Major) Coadministration of dofetilide and moxifloxacin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Quinolones have been associated with a risk of QT prolongation. Although extremely rare, TdP has been reported during postmarketing surveillance of moxifloxacin. These reports generally involved patients with concurrent medical conditions or concomitant medications that may have been contributory.
Nefazodone: (Major) Nefazodone may reduce the metabolism of dofetilide via CYP3A4 inhibition. This interaction may result in increased dofetilide plasma concentrations and risk for QTc prolongation.
Nelfinavir: (Major) Coadministration of CYP3A4 inhibitors, such as nelfinavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Nevirapine: (Minor) Coadministration of dofetilide with inducers of CYP3A4, such as nevirapine, may increase the metabolism of dofetilide.
Nicardipine: (Moderate) Nicardipine is an inhibitor of CYP3A4 isoenzymes. Co-administration with nicardipine may lead to an increase in serum levels of drugs that are CYP3A4 substrates including doeftilide.
Nilotinib: (Major) Coadministration of dofetilide and nilotinib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Sudden death and QT interval prolongation have occurred in patients who received nilotinib therapy.
Nirmatrelvir; Ritonavir: (Major) Avoid concomitant use of ritonavir-boosted nirmatrelvir and dofetilide and consider an alternative COVID-19 therapy. Coadministration may increase dofetilide exposure resulting in increased toxicity. Dofetilide is a CYP3A substrate and nirmatrelvir is a CYP3A inhibitor. (Moderate) Concomitant use of dofetilide and ritonavir may increase the risk of QT prolongation and torsade de pointes (TdP) due to increased dofetilide exposure. Dofetilide is metabolized to a small degree by CYP3A4; ritonavir is a potent inhibitor of CYP3A4.
Norfloxacin: (Contraindicated) Quinolones have been associated with a risk of QT prolongation and torsade de pointes (TdP). Although extremely rare, torsade de pointes has been reported during post-marketing surveillance of norfloxacin. These reports generally involved patients with concurrent medical conditions or concomitant medications that may have been contributory. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Because of the potential for TdP, use of dofetilide with norfloxacin is contraindicated.
Octreotide: (Major) Coadministration of dofetilide and octreotide is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Arrhythmias, sinus bradycardia, and conduction disturbances have occurred during octreotide therapy. Since bradycardia is a risk factor for development of TdP, the potential occurrence of bradycardia during octreotide administration could theoretically increase the risk of TdP in patients receiving drugs that prolong the QT interval.
Ofloxacin: (Major) Coadministration of dofetilide and ofloxacin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Quinolones have been associated with a risk of QT prolongation and TdP. Although extremely rare, TdP has been reported during postmarketing surveillance of ofloxacin. These reports generally involved patients with concurrent medical conditions or concomitant medications that may have been contributory.
Olanzapine: (Major) Coadministration of dofetilide and olanzapine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval.
Olanzapine; Fluoxetine: (Major) Coadministration of dofetilide and fluoxetine is not recommended as concurrent use may increase the risk of QT prolongation and torsade de pointes (TdP). QT prolongation and TdP have been reported in patients treated with fluoxetine. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. The use of dofetilide with other drugs that prolong the QT interval has not been studied and is not recommended. (Major) Coadministration of dofetilide and olanzapine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval.
Olanzapine; Samidorphan: (Major) Coadministration of dofetilide and olanzapine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval.
Olmesartan; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Concomitant use of dofetilide and ritonavir may increase the risk of QT prolongation and torsade de pointes (TdP) due to increased dofetilide exposure. Dofetilide is metabolized to a small degree by CYP3A4; ritonavir is a potent inhibitor of CYP3A4.
Ondansetron: (Major) Coadministration of dofetilide and ondansetron is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, ECG monitoring is recommended. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of TdP.
Osilodrostat: (Major) Coadministration of dofetilide and osilodrostat is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Osilodrostat is associated with dose-dependent QT prolongation.
Osimertinib: (Major) Avoid coadministration of dofetilide with osimertinib if possible due to the risk of QT prolongation and torsade de pointes (TdP). If concomitant use is unavoidable, periodically monitor ECGs for QT prolongation and monitor electrolytes; an interruption of osimertinib therapy with dose reduction or discontinuation may be necessary if QT prolongation occurs. Concentration-dependent QTc prolongation occurred during clinical trials of osimertinib. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP).
Oxaliplatin: (Major) Coadministration of dofetilide and oxaliplatin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation and ventricular arrhythmias including fatal TdP have been reported with oxaliplatin use in postmarketing experience.
Ozanimod: (Major) In general, do not initiate ozanimod in patients taking dofetilide due to the risk of additive bradycardia, QT prolongation, and torsade de pointes (TdP). If treatment initiation is considered, seek advice from a cardiologist. Ozanimod initiation may result in a transient decrease in heart rate and atrioventricular conduction delays. Ozanimod has not been studied in patients taking concurrent QT prolonging drugs; however, QT prolonging drugs have been associated with TdP in patients with bradycardia. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Pacritinib: (Major) Concomitant use of dofetilide and pacritinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Concomitant use may also increase dofetilide exposure and the risk for other dofetilide-related adverse effects. Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring. Pacritinib is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of TdP.
Palbociclib: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with palbociclib is necessary. Palbociclib is a weak time-dependent CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Paliperidone: (Major) Coadministration of dofetilide and paliperidone is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of Paliperidone has been associated with QT prolongation; torsade de pointes and ventricular fibrillation have been reported in the setting of overdose.
Panobinostat: (Major) Coadministration of dofetilide and panobinostat is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation has been reported with panobinostat.
Pasireotide: (Major) Coadministration of dofetilide and pasireotide is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). QT prolongation has occurred with pasireotide at therapeutic and supra-therapeutic doses.
Pazopanib: (Major) Coadministration of dofetilide and pazopanib is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, closely monitor the patient for QT interval prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Pazopanib has been reported to prolong the QT interval.
Pentamidine: (Major) Coadministration of dofetilide and pentamidine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of Systemic pentamidine has been associated with QT prolongation.
Perindopril; Amlodipine: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Perphenazine: (Minor) Perphenazine is associated with a possible risk for QT prolongation. Theoretically, perphenazine may increase the risk of QT prolongation if coadministered with other drugs that have a risk of QT prolongation, such as dofetilide.
Perphenazine; Amitriptyline: (Minor) Perphenazine is associated with a possible risk for QT prolongation. Theoretically, perphenazine may increase the risk of QT prolongation if coadministered with other drugs that have a risk of QT prolongation, such as dofetilide.
Pimavanserin: (Major) Coadministration of dofetilide and pimavanserin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of Pimavanserin prolongs the QT interval.
Pimozide: (Contraindicated) Coadministration of pimozide with dofetilide is contraindicated due to the potential for QT prolongation and torsade de pointes (TdP). Both drugs are associated with a well-established risk of QT prolongation and TdP.
Pioglitazone; Metformin: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
Pitolisant: (Major) Coadministration of dofetilide and pitolisant is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Pitolisant also prolongs the QT interval.
Ponesimod: (Major) In general, do not initiate ponesimod in patients taking dofetilide due to the risk of additive bradycardia, QT prolongation, and torsade de pointes (TdP). If treatment initiation is considered, seek advice from a cardiologist. Ponesimod initiation may result in a transient decrease in heart rate and atrioventricular conduction delays. Ponesimod has not been studied in patients taking concurrent QT prolonging drugs; however, QT prolonging drugs have been associated with TdP in patients with bradycardia. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP.
Posaconazole: (Contraindicated) The concurrent use of posaconazole with drugs that are associated with QT prolongation and are also CYP3A4 substrates, such as dofetilide, is contraindicated. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Posaconazole has also been associated with QT prolongation and TdP.
Prednisolone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Prednisone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Prilocaine; Epinephrine: (Moderate) Monitor patients who receive epinephrine while concomitantly taking antiarrhythmics for the development of arrhythmias. Epinephrine may produce ventricular arrhythmias in patients who are on drugs that may sensitize the heart to arrhythmias.
Primaquine: (Major) Coadministration of dofetilide and primaquine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Primaquine has been associated with QT prolongation.
Procainamide: (Contraindicated) Coadministration of dofetilide and procainamide is contraindicated as concurrent use may increase the risk of QT prolongation and torsade de pointes (TdP). Class I antiarrhythmic agents, such as procainamide, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Procainamide is also associated with a well-established risk of QT prolongation and TdP.
Prochlorperazine: (Contraindicated) Coadministration of dofetilide and prochlorperazine is contraindicated as concurrent use may increase the risk QT prolongation and torsades de pointes (TdP). Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Prochlorperazine is associated with a possible risk for QT prolongation. Additionally, prochlorperazine is an inhibitor of the renal cation transport system which may result in increased dofetilide exposure, further increasing the risk of cardiac-related adverse effects.
Promethazine: (Major) Coadministration of dofetilide and promethazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Promethazine, a phenothiazine, is associated with a possible risk for QT prolongation.
Promethazine; Dextromethorphan: (Major) Coadministration of dofetilide and promethazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Promethazine, a phenothiazine, is associated with a possible risk for QT prolongation.
Promethazine; Phenylephrine: (Major) Coadministration of dofetilide and promethazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Promethazine, a phenothiazine, is associated with a possible risk for QT prolongation.
Propafenone: (Major) Coadministration of dofetilide and propafenone is not recommended as concurrent use may increase the risk of QT prolongation. Class I antiarrhythmic agents, such as propafenone, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Propafenone is a Class IC antiarrhythmic which increases the QT interval, but largely due to prolongation of the QRS interval.
Quetiapine: (Major) Coadministration of dofetilide and quetiapine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Limited data, including some case reports, suggest that quetiapine may be associated with a significant prolongation of the QTc interval in rare instances.
Quinidine: (Contraindicated) Coadministration of dofetilide and quinidine is contraindicated as concurrent use may increase the risk QT prolongation and torsades de pointes (TdP). Class I antiarrhythmic agents, such as quinidine, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Quinidine administration is associated with QT prolongation and TdP.
Quinine: (Contraindicated) Coadministration of dofetilide and quinine is contraindicated as concurrent use may increase the risk QT prolongation and torsades de pointes (TdP). Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Quinine has been associated with QT prolongation and rare cases of TdP.
Ranolazine: (Major) Coadministration of dofetilide and ranolazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Ranolazine is associated with dose- and plasma concentration-related increases in the QTc interval.
Relugolix: (Major) Coadministration of dofetilide and relugolix is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Androgen deprivation therapy (i.e., relugolix) may also prolong the QT/QTc interval.
Relugolix; Estradiol; Norethindrone acetate: (Major) Coadministration of dofetilide and relugolix is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Androgen deprivation therapy (i.e., relugolix) may also prolong the QT/QTc interval.
Ribociclib: (Major) Coadministration of dofetilide and ribociclib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Ribociclib has been shown to prolong the QT interval in a concentration-dependent manner. The ribociclib ECG changes occurred within the first four weeks of treatment and were reversible with dose interruption.
Ribociclib; Letrozole: (Major) Coadministration of dofetilide and ribociclib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Ribociclib has been shown to prolong the QT interval in a concentration-dependent manner. The ribociclib ECG changes occurred within the first four weeks of treatment and were reversible with dose interruption.
Rilpivirine: (Major) Coadministration of dofetilide and rilpivirine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Supratherapeutic doses of rilpivirine (75 to 300 mg/day) have caused QT prolongation.
Risperidone: (Major) Coadministration of dofetilide and risperidone is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Risperidone has been associated with a possible risk for QT prolongation and/or TdP, primarily in the overdose setting.
Ritonavir: (Moderate) Concomitant use of dofetilide and ritonavir may increase the risk of QT prolongation and torsade de pointes (TdP) due to increased dofetilide exposure. Dofetilide is metabolized to a small degree by CYP3A4; ritonavir is a potent inhibitor of CYP3A4.
Romidepsin: (Major) Coadministration of dofetilide and romidepsin is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor electrolytes and ECGs at baseline and periodically during treatment. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Romidepsin has been reported to prolong the QT interval.
Rucaparib: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with rucaparib is necessary. Rucaparib is a weak CYP3A4 inhibitor and dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Saquinavir: (Contraindicated) Coadministration of saquinavir boosted with ritonavir with dofetilide is contraindicated as concurrent use may increase dofetilide exposure and risk of QT prolongation. Saquinavir boosted with ritonavir is strong CYP3A4 inhibitor that increases the QT interval in a dose-dependent fashion, which may increase the risk for serious arrhythmias such as torsade de pointes (TdP). Dofetilide, a Class III antiarrhythmic agent, is a CYP3A4 substrate that is associated with a well-established risk of QT prolongation and TdP.
Selpercatinib: (Major) Coadministration of dofetilide and selpercatinib is not recommended as concurrent use may increase the risk of QT prolongation. Monitor ECGs more frequently for QT prolongation if coadministration is necessary. Dofetilide exposure may be increased. Dofetilide, a Class III antiarrhythmic agent, is a CYP3A4 substrate that is associated with a well-established risk of QT prolongation and TdP. Selpercatinib is a weak CYP3A4 inhibitor that is associated with concentration-dependent QT prolongation.
Sertraline: (Major) Coadministration of dofetilide and sertraline is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, use caution and monitor patients for signs and symptoms of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Although sertralines FDA-approved labeling recommends avoiding concomitant use with drugs known to prolong the QTc interval, the risk of sertraline-induced QT prolongation is generally considered to be low in clinical practice. Its effect on QTc interval is minimal (typically less than 5 msec), and the drug has been used safely in patients with cardiac disease (e.g., recent myocardial infarction, unstable angina, chronic heart failure).
Sevoflurane: (Major) Coadministration of dofetilide and halogenated anesthetics is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Halogenated anesthetics can prolong the QT interval.
Siponimod: (Major) Coadministration of dofetilide and siponimod is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, consult a cardiologist regarding appropriate monitoring. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Siponimod therapy prolonged the QT interval at recommended doses in a clinical study.
Solifenacin: (Major) Coadministration of dofetilide and solifenacin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Solifenacin has been associated with dose-dependent prolongation of the QT interval. TdP has been reported with postmarketing use, although causality was not determined.
Sorafenib: (Major) Coadministration of dofetilide and sorafenib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Sorafenib is associated with QTc prolongation.
Sotalol: (Major) Coadministration of dofetilide and sotalol is not recommended as concurrent use may increase the risk of QT prolongation. Class III antiarrhythmic agents, such as sotalol, should be withheld for at least 3 half-lives prior to initiating dofetilide therapy. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Sotalol administration is associated with QT prolongation and torsade de pointes (TdP). Proarrhythmic events should be anticipated after initiation of therapy and after each upward dosage adjustment.
Spironolactone: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with spironolactone is necessary as concurrent use may increase dofetilide exposure. Spironolactone is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Spironolactone; Hydrochlorothiazide, HCTZ: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with spironolactone is necessary as concurrent use may increase dofetilide exposure. Spironolactone is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
St. John's Wort, Hypericum perforatum: (Major) St. John's Wort appears to induce several isoenzymes of the hepatic cytochrome P450 enzyme system, including CYP3A4, Co-administration of St. John's wort could decrease the efficacy of some medications metabolized by CYP3A4, such as dofetilide. Clinicians should observe patients closely if St. John's wort is used.
Streptogramins: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with dalfopristin; quinupristin is necessary. Dalfopristin; quinupristin is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Contraindicated) Concomitant use of dofetilide with trimethoprim is contraindicated due to increased plasma concentrations of dofetilide, which may cause serious ventricular arrhythmias associated with QT prolongation, including torsade de pointes (TdP). Trimethoprim is an inhibitor of the renal cation transport system and decreases the active tubular secretion of dofetilide. The combination of trimethoprim 160 mg and 800 mg sulfamethoxazole co-administered twice daily with dofetilide 500 mcg for 4 days has been shown to increase dofetilide AUC by 93% and Cmax by 103%.
Sunitinib: (Major) Coadministration of dofetilide and sunitinib is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Sunitinib can prolong the QT interval.
Tacrolimus: (Major) Coadministration of dofetilide and tacrolimus is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor ECG and electrolytes periodically during treatment. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Tacrolimus may prolong the QT interval and cause TdP.
Tafenoquine: (Contraindicated) Coadministration of dofetilide and tafenoquine is contraindicated due to the potential for increased dofetilide concentrations and arrhythmias (QT prolongation and torsade de pointes). The effect of coadministration of tafenoquine on the pharmacokinetics of OCT2 and MATE substrates, like dofetilide, in humans is unknown; however, in vitro observations suggest the potential for increased concentrations of OCT2 and MATE substrates. Dofetilide is eliminated by cationic renal secretion, and tafenoquine may interfere with the renal elimination of dofetilide.
Tamoxifen: (Major) Coadministration of dofetilide and tamoxifen is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Tamoxifen has been reported to prolong the QT interval, usually in overdose or when used in high doses. Rare case reports of QT prolongation have also been described when tamoxifen is used at lower doses.
Telavancin: (Major) Coadministration of dofetilide and telavancin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Telavancin has been associated with QT prolongation.
Telithromycin: (Major) Coadministration of dofetilide and telithromycin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Telithromycin is also associated with QT prolongation and TdP.
Telmisartan; Amlodipine: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with amlodipine is necessary. Amlodipine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Tenofovir Alafenamide: (Major) Dofetilide should be co-administered with tenofovir alafenamide with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended.
Tenofovir, PMPA: (Major) Dofetilide should be co-administered with tenofovir, PMPA with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of dofetilide is recommended.
Tetrabenazine: (Major) Coadministration of dofetilide and tetrabenazine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Tetrabenazine causes a small increase in the corrected QT interval (QTc).
Thiazide diuretics: (Contraindicated) Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs such as loop diuretics and thiazide diuretics, increasing the potential for dofetilide-induced torsade de pointes. Additionally, in patients treated with either hydrochlorothiazide 50 mg or hydrochlorothiazide/triamterene 50 mg/100 mg daily in combination with dofetilide 500 mcg twice daily for 5 days, dofetilide AUC and Cmax concentrations increased by 27% and 21%, respectively, for the hydrochlorothiazide alone group and by 30% and 16%, respectively, for the hydrochlorothiazide/triamterene group. Furthermore, a 197% and 190% QTc increase over time was seen in the hydrochlorothiazide and hydrochlorothiazide/triamterene groups, respectively. Based on these findings, the manufacturer of dofetilide contraindicates the concomitant use of hydrochlorothiazide (alone or in combination with other drugs such as triamterene); these findings can be explained both by an increase in the plasma concentration of dofetilide and a reduction in the serum potassium concentration. In a population pharmacokinetic analysis of plasma dofetilide concentrations, the mean dofetilide clearance of dofetilide was 16% lower in patients on thiazide diuretics. It is prudent to avoid the use of any thiazide diuretic in combination with dofetilide.
Thioridazine: (Contraindicated) Coadministration of thioridazine with dofetilide is contraindicated due to the potential for QT prolongation and torsade de pointes (TdP). Both drugs are associated with a well-established risk of QT prolongation and TdP.
Tipranavir: (Major) Coadministration of CYP3A4 inhibitors, such as tipranavir, with dofetilide may decrease the metabolism of dofetilide, thereby increasing the potential for QT prolongation. Dofetilide is a Class III antiarrhythmic agent that has a well-established risk of QT prolongation and torsade de pointes (TdP). Plasma dofetilide concentrations are correlated with the risk of drug-induced proarrhythmias.
Tocainide: (Contraindicated) Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsades de pointes (TdP). Before switching from another antiarrhythmic drug to dofetilide therapy, antiarrhythmics generally should be withheld for at least three half-lives prior to initiating dofetilide. According to the manufacturer, Class I (disopyramide, encainide, flecainide, lidocaine, mexiletine, moricizine, procainamide, propafenone, quinidine, and tocainide) and Class III (e.g., amiodarone, bretylium, ibutilide, and sotalol) antiarrhythmic agents are associated with QT prolongation and ventricular arrhythmias and concurrent exposure with dofetilide could increase the risk of dofetilide-induced proarrhythmias.
Tolterodine: (Major) Coadministration of dofetilide and tolterodine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Tolterodine has been associated with dose-dependent prolongation of the QT interval, especially in poor CYP2D6 metabolizers.
Toremifene: (Major) Coadministration of dofetilide and toremifene is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, closely monitor ECGs for QT prolongation and monitor electrolytes. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Toremifene has been shown to prolong the QTc interval in a dose- and concentration-related manner.
Trandolapril; Verapamil: (Contraindicated) The concomitant use of verapamil (CYP3A4 inhibitor) and dofetilide is contraindicated. Coadministration of dofetilide with verapamil increased dofetilide peak plasma concentrations by 42%, although the overall exposure to dofetilide was not significantly increased. Concurrent use of verapamil and dofetilide was also associated with a higher occurrence of torsade de pointes in dofetilide clinical trials.
Trazodone: (Major) Coadministration of dofetilide and trazodone is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Trazodone can prolong the QT/QTc interval at therapeutic doses. In addition, there are postmarketing reports of TdP.
Triamcinolone: (Major) Corticosteroids can cause increases in blood pressure, sodium and water retention, and hypokalemia, predisposing patients to interactions with certain other medications. Corticosteroid-induced hypokalemia could also enhance the proarrhythmic effects of dofetilide.
Triamterene: (Major) Drugs that are actively secreted via cationic tubular secretion, such as triamterene, should be co-administered with caution with dofetilide since they could increase dofetilide plasma concentrations via potential competition for renal cationic secretion. Increased dofetilide plasma concentrations may be associated with proarrhythmias.
Triamterene; Hydrochlorothiazide, HCTZ: (Major) Drugs that are actively secreted via cationic tubular secretion, such as triamterene, should be co-administered with caution with dofetilide since they could increase dofetilide plasma concentrations via potential competition for renal cationic secretion. Increased dofetilide plasma concentrations may be associated with proarrhythmias.
Triclabendazole: (Major) Coadministration of dofetilide and triclabendazole is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor ECGs during treatment. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Transient prolongation of the mean QTc interval was noted on the ECG recordings in dogs administered triclabendazole.
Trifluoperazine: (Minor) Trifluoperazine is associated with a possible risk for QT prolongation. Theoretically, trifluoperazine may increase the risk of QT prolongation if coadministered with other drugs that have a risk of QT prolongation such as dofetilide.
Trilaciclib: (Contraindicated) Concomitant use of dofetilide and trilaciclib is contraindicated. This combination may increase dofetilide exposure and the risk of dofetilide-related adverse effects including drug-induced QT prolongation and torsade de pointes (TdP). Dofetilide is an OCT2 substrate; trilaciclib is an OCT2 inhibitor.
Trimethoprim: (Contraindicated) Concomitant use of dofetilide with trimethoprim is contraindicated due to increased plasma concentrations of dofetilide, which may cause serious ventricular arrhythmias associated with QT prolongation, including torsade de pointes (TdP). Trimethoprim is an inhibitor of the renal cation transport system and decreases the active tubular secretion of dofetilide. The combination of trimethoprim 160 mg and 800 mg sulfamethoxazole co-administered twice daily with dofetilide 500 mcg for 4 days has been shown to increase dofetilide AUC by 93% and Cmax by 103%.
Triptorelin: (Major) Coadministration of dofetilide and triptorelin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Androgen deprivation therapy (i.e., triptorelin) may prolong the QT/QTc interval.
Trospium: (Major) Drugs that are actively secreted via cationic secretion (e.g., trospium) should be co-administered with dofetilide with caution since they could increase dofetilide plasma concentrations via potential competition for renal tubular secretion.
Tucatinib: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with tucatinib is necessary as concurrent use may increase dofetilide exposure. Tucatinib is a strong CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Vandetanib: (Major) Coadministration of dofetilide and vandetanib is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, monitor ECGs for QT prolongation and monitor electrolytes; correct hypocalcemia, hypomagnesemia, and/or hypomagnesemia prior to vandetanib administration. An interruption of vandetanib therapy or dose reduction may be necessary for QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Vandetanib can prolong the QT interval in a concentration-dependent manner; TdP and sudden death have been reported in patients receiving vandetanib.
Vardenafil: (Major) Coadministration of dofetilide and vardenafil is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Vardenafil is associated with QT prolongation. Both therapeutic and supratherapeutic doses of vardenafil produce an increase in QTc interval.
Vemurafenib: (Major) Coadministration of dofetilide and vemurafenib is not recommended as concurrent use may increase the risk of QT prolongation. If coadministration cannot be avoided, ECG monitoring is recommended; closely monitor the patient for QT interval prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Vemurafenib has been associated with QT prolongation.
Venlafaxine: (Major) Coadministration of dofetilide and venlafaxine is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Venlafaxine administration is associated with a possible risk of QT prolongation; TdP has been reported with postmarketing use.
Verapamil: (Contraindicated) The concomitant use of verapamil (CYP3A4 inhibitor) and dofetilide is contraindicated. Coadministration of dofetilide with verapamil increased dofetilide peak plasma concentrations by 42%, although the overall exposure to dofetilide was not significantly increased. Concurrent use of verapamil and dofetilide was also associated with a higher occurrence of torsade de pointes in dofetilide clinical trials.
Viloxazine: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with viloxazine is necessary as concurrent use may increase dofetilide exposure. viloxazine is a weak CYP3A4 inhibitor. Dofetilide is a minor CYP3A4 substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A4 inhibitors may increase the risk of arrhythmia (torsade de pointes).
Voclosporin: (Major) Concomitant use of dofetilide and voclosporin is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Voclosporin has been associated with QT prolongation with supratherapeutic doses.
Voriconazole: (Major) Coadministration of dofetilide and voriconazole is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Voriconazole has been associated with QT prolongation and rare cases of TdP.
Vorinostat: (Major) Coadministration of dofetilide and vorinostat is not recommended as concurrent use may increase the risk of QT prolongation. Dofetilide, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Vorinostat therapy is associated with a risk of QT prolongation.
Voxelotor: (Moderate) Monitor for an increase in dofetilide-related adverse reactions, including QT prolongation, if coadministration with voxelotor is necessary as concurrent use may increase dofetilide exposure. Voxelotor is a moderate CYP3A inhibitor. Dofetilide is a minor CYP3A substrate; however, because there is a linear relationship between dofetilide plasma concentration and QTc, concomitant administration of CYP3A inhibitors may increase the risk of arrhythmia (torsade de pointes).
Zafirlukast: (Major) Zafirlukast, a CYP 3A4 inhibitor, may increase plasma dofetilide concentrations with potential for dofetilide toxicity.
Ziprasidone: (Contraindicated) Concomitant use of ziprasidone and class III antiarrhythmics, such as dofetilide, is contraindicated by the manufacturer of ziprasidone due to the potential for additive QT prolongation and torsade de pointes (TdP). Clinical trial data indicate that ziprasidone causes QT prolongation; there are postmarketing reports of TdP in patients with multiple confounding factors. Class III antiarrhythmics are associated with a well-established risk of QT prolongation and TdP.