dapsone

Agents for Leprosy
Other Topical Agents for Acne

Dapsone may be administered orally without regard to meals.

Extemporaneous oral suspension: Shake well before administering. Measure dosage with calibrated measuring device.

NOTE: Extemporaneously compounded oral dapsone suspension is not FDA-approved.
Extemporaneous preparation of 2 mg/mL dapsone oral suspension
Using a mortar and pestle, grind sixteen 25-mg dapsone tablets to a fine powder.
Add a small amount of vehicle (1:1 mixture of Ora-Plus and Ora-Sweet) and mix to a uniform paste.
Add geometric proportions of vehicle to almost desired volume while continuing to mix then transfer to graduated cylinder.
Rinse mortar and pestle with vehicle and transfer to graduated cylinder.
Add enough vehicle to bring the final volume to 200 mL.
Storage: The oral suspension is stable for 90 days when stored at room temperature or refrigerated.

Before applying topical formulations of dapsone, gently cleanse affected area with a mild soap and pat skin dry.

Gel Formulation:
Apply a thin layer to the acne affected area as directed. Rub the gel into the skin gently and completely. Aczone gel is gritty with visible drug substance particles present. Wash hands immediately after applying.

methemoglobinemia / Early / 10.0
vasculitis / Delayed / 10.0
hemolytic anemia / Delayed / Incidence not known
agranulocytosis / Delayed / Incidence not known
aplastic anemia / Delayed / Incidence not known
exfoliative dermatitis / Delayed / Incidence not known
toxic epidermal necrolysis / Delayed / Incidence not known
erythema multiforme / Delayed / Incidence not known
erythema nodosum / Delayed / Incidence not known
nephrotic syndrome / Delayed / Incidence not known
renal papillary necrosis / Delayed / Incidence not known
pancreatitis / Delayed / Incidence not known
eosinophilic pneumonia / Delayed / Incidence not known
lupus-like symptoms / Delayed / Incidence not known

erythema / Early / 13.0-13.0
peripheral neuropathy / Delayed / 0-1.0
hemolysis / Early / 10.0
anemia / Delayed / 10.0
depression / Delayed / 10.0
neuritis / Delayed / 10.0
iritis / Delayed / 10.0
bullous rash / Early / Incidence not known
elevated hepatic enzymes / Delayed / Incidence not known
hyperbilirubinemia / Delayed / Incidence not known
jaundice / Delayed / Incidence not known
hepatitis / Delayed / Incidence not known
psychosis / Early / Incidence not known
blurred vision / Early / Incidence not known
hypoalbuminemia / Delayed / Incidence not known
sinus tachycardia / Rapid / Incidence not known
infertility / Delayed / Incidence not known

xerosis / Delayed / 0-16.0
pharyngitis / Delayed / 2.0-5.0
headache / Early / 4.0-4.0
infection / Delayed / 3.0-3.0
cough / Delayed / 2.0-2.0
sinusitis / Delayed / 2.0-2.0
pruritus / Rapid / 1.0-1.0
weakness / Early / 0-1.0
influenza / Delayed / 1.0-1.0
epistaxis / Delayed / 10.0
malaise / Early / 10.0
fever / Early / 10.0
urticaria / Rapid / Incidence not known
photosensitivity / Delayed / Incidence not known
rash / Early / Incidence not known
vomiting / Early / Incidence not known
nausea / Early / Incidence not known
abdominal pain / Early / Incidence not known
insomnia / Early / Incidence not known
vertigo / Early / Incidence not known
tinnitus / Delayed / Incidence not known

Aczone

Rx

Synthetic sulfone chemically similar to sulfonamides
Has antiinfective and immunosuppressive properties
Agent of choice for all forms of leprosy; used for PCP prophylaxis; used in combination with pyrimethamine for prevention of toxoplasmosis in AIDS patients; used for various dermatologic disorders and topically for acne.

Dapsone can cause toxic hepatitis and cholestatic jaundice, however, specific dosage adjustment guidelines in patients with hepatic impairment are not available. Hepatic function should be monitored before and during treatment with dapsone.

No dosage adjustment needed.

Abacavir; Lamivudine, 3TC; Zidovudine, ZDV: (Minor) Zidovudine, ZDV should be given with caution to patients also receiving dapsone due to the risk of additive hematologic toxicity.
Acetaminophen: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Aspirin, ASA; Caffeine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Aspirin: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Aspirin; Diphenhydramine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Caffeine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Caffeine; Dihydrocodeine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Caffeine; Pyrilamine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Chlorpheniramine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Codeine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Dextromethorphan: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Dextromethorphan; Doxylamine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Dichloralphenazone; Isometheptene: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Diphenhydramine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Guaifenesin; Phenylephrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Hydrocodone: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Ibuprofen: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Oxycodone: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Pamabrom; Pyrilamine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Phenylephrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Acetaminophen; Pseudoephedrine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Adapalene; Benzoyl Peroxide: (Minor) Coadministration of topical benzoyl peroxide-containing products with topical sulfone products, such as dapsone, may cause skin and facial hair to temporarily change color to a yellow/orange color.
Apalutamide: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with apalutamide is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and apalutamide is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Aprepitant, Fosaprepitant: (Moderate) Use caution if dapsone and aprepitant, fosaprepitant are used concurrently and monitor for an increase in dapsone-related adverse effects for several days after administration of a multi-day aprepitant regimen. Dapsone is a CYP3A4 substrate. 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 dapsone. For example, a 5-day oral aprepitant regimen increased the AUC of another CYP3A4 substrate, midazolam (single dose), by 2.3-fold on day 1 and by 3.3-fold on day 5. 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.
Armodafinil: (Minor) The metabolism of dapsone may be accelerated when administered concurrently with armodafinil, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Articaine; Epinephrine: (Moderate) Coadministration of dapsone with articaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Atazanavir; Cobicistat: (Minor) Plasma concentrations of dapsone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Cobicistat is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Benzalkonium Chloride; Benzocaine: (Moderate) Coadministration of dapsone with benzocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Benzhydrocodone; Acetaminophen: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Benzocaine: (Moderate) Coadministration of dapsone with benzocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Benzocaine; Butamben; Tetracaine: (Moderate) Coadministration of dapsone with benzocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Benzoyl Peroxide: (Minor) Coadministration of topical benzoyl peroxide-containing products with topical sulfone products, such as dapsone, may cause skin and facial hair to temporarily change color to a yellow/orange color.
Benzoyl Peroxide; Clindamycin: (Minor) Coadministration of topical benzoyl peroxide-containing products with topical sulfone products, such as dapsone, may cause skin and facial hair to temporarily change color to a yellow/orange color.
Benzoyl Peroxide; Erythromycin: (Minor) Coadministration of topical benzoyl peroxide-containing products with topical sulfone products, such as dapsone, may cause skin and facial hair to temporarily change color to a yellow/orange color.
Benzoyl Peroxide; Sulfur: (Minor) Coadministration of topical benzoyl peroxide-containing products with topical sulfone products, such as dapsone, may cause skin and facial hair to temporarily change color to a yellow/orange color.
Bexarotene: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with bexarotene is necessary. Dapsone is a CYP3A4 substrate and bexarotene is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Bortezomib: (Minor) Monitor patients for the development of peripheral neuropathy when receiving bortezomib in combination with other drugs that can cause peripheral neuropathy like dapsone; the risk of peripheral neuropathy may be additive.
Bosentan: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with bosentan is necessary. Dapsone is a CYP3A4 substrate and bosentan is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Bupivacaine Liposomal: (Moderate) Coadministration of dapsone with bupivacaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Bupivacaine: (Moderate) Coadministration of dapsone with bupivacaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Bupivacaine; Epinephrine: (Moderate) Coadministration of dapsone with bupivacaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Bupivacaine; Lidocaine: (Moderate) Coadministration of dapsone with bupivacaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia. (Moderate) Coadministration of dapsone with lidocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Bupivacaine; Meloxicam: (Moderate) Coadministration of dapsone with bupivacaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Butalbital; Acetaminophen: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Butalbital; Acetaminophen; Caffeine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Butalbital; Acetaminophen; Caffeine; Codeine: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Carbamazepine: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with carbamazepine is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and carbamazepine is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Cenobamate: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with cenobamate is necessary. Dapsone is a CYP3A4 substrate and cenobamate is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Charcoal: (Moderate) Patients who ingest activated charcoal as a dietary supplement for flatulence or other purposes should be aware that the effectiveness of other regularly taken medications (e.g., dapsone) may be decreased. In some drug overdoses, such as dapsone overdose, multiple-doses of charcoal slurries are an effective therapeutic adjunct. Repeat doses may decrease the entero-hepatic recycling of some of these agents.
Chloroprocaine: (Moderate) Coadministration of dapsone with chloroprocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Chloroquine: (Moderate) Coadministration of dapsone with chloroquine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Ciprofloxacin: (Moderate) Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration of dapsone and ciprofloxacin. Plasma concentrations of dapsone may be elevated when administered concurrently with ciprofloxacin. Ciprofloxacin is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Cobicistat: (Minor) Plasma concentrations of dapsone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Cobicistat is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Dabrafenib: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with dabrafenib is necessary. Dapsone is a CYP3A4 substrate and dabrafenib is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Darunavir: (Minor) The plasma concentrations of dapsone may be elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Darunavir is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Darunavir; Cobicistat: (Minor) Plasma concentrations of dapsone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Cobicistat is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate. (Minor) The plasma concentrations of dapsone may be elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Darunavir is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Minor) Plasma concentrations of dapsone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Cobicistat is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate. (Minor) The plasma concentrations of dapsone may be elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Darunavir is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Deferasirox: (Moderate) The metabolism of dapsone may be accelerated when administered concurrently with deferasirox, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Didanosine, ddI: (Moderate) Dapsone clinical failures have been noted when dapsone was administered with didanosine. Despite a lack of a documented pharmacokinetic interaction, clinicians should be wary of possible dapsone clinical failure when dapsone is used with didanosine since this has been reported previously.
Dronedarone: (Moderate) Dronedarone is metabolized by and is an inhibitor of CYP3A. Dapsone is a substrate for CYP3A4. The concomitant administration of dronedarone and CYP3A substrates may result in increased exposure of the substrate and should, therefore, be undertaken with caution.
Efavirenz: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with efavirenz is necessary. Dapsone is a CYP3A4 substrate and efavirenz is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with efavirenz is necessary. Dapsone is a CYP3A4 substrate and efavirenz is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with efavirenz is necessary. Dapsone is a CYP3A4 substrate and efavirenz is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Elbasvir; Grazoprevir: (Minor) Administering dapsone with grazoprevir may result in elevated dapsone plasma concentrations. Dapsone is a substrate of CYP3A; grazoprevir is a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of adverse events.
Elexacaftor; tezacaftor; ivacaftor: (Major) If dapsone and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Ivacaftor is a CYP3A substrate and dapsone is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Minor) Plasma concentrations of dapsone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Cobicistat is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Minor) Plasma concentrations of dapsone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as hemolytic anemia, methemoglobinemia, or peripheral neuropathy, is recommended during coadministration. Cobicistat is a CYP3A4 inhibitor, while dapsone is a CYP3A4 substrate.
Enzalutamide: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with enzalutamide is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and enzalutamide is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Eslicarbazepine: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with eslicarbazepine is necessary. Dapsone is a CYP3A4 substrate and eslicarbazepine is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Etravirine: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with etravirine is necessary. Dapsone is a CYP3A4 substrate and etravirine is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Felbamate: (Minor) The metabolism of dapsone may be accelerated when administered concurrently with felbamate, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Fluorouracil, 5-FU: (Major) Agranulocytosis has been reported in the second to third month of weekly concomitant treatment with dapsone and other hemolytic agents such as fluorouracil. These combinations increase the likelihood of adverse hematologic events.
Flutamide: (Moderate) The metabolism of dapsone may be accelerated when administered concurrently with flutamide, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Fosamprenavir: (Minor) Fosamprenavir may inhibit the metabolism of other medications that are metabolized via cytochrome P450 3A4. Although drug interaction studies have not been conducted, the serum concentrations of dapsone may be increased with concomitant administration of fosamprenavir.
Fosphenytoin: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with fosphenytoin is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and fosphenytoin is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage. Also, coadministration of dapsone with fosphenytoin may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Ganciclovir: (Moderate) Use ganciclovir and dapsone together only if the potential benefits outweigh the risks; bone marrow suppression, spermatogenesis inhibition, skin toxicity, and gastrointestinal toxicity may be additive as both drugs inhibit rapidly dividing cells.
Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Coadministration of dapsone with nitrates may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with dapsone, a CYP3A substrate, as dapsone toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib.
Imatinib: (Minor) Imatinib, STI-571 may inhibit the metabolism of dapsone and leading to increased levels and potential toxicity. Monitor patients closely who receive concurrent therapy.
Isavuconazonium: (Moderate) Concomitant use of isavuconazonium with dapsone may result in increased serum concentrations of dapsone. Dapsone is a substrate of the hepatic isoenzyme CYP3A4; isavuconazole, the active moiety of isavuconazonium, is a moderate inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are used together.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with rifampin is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and rifampin is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with rifampin decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Isoniazid, INH; Rifampin: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with rifampin is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and rifampin is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with rifampin decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Isosorbide Dinitrate, ISDN: (Moderate) Coadministration of dapsone with nitrates may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Isosorbide Mononitrate: (Moderate) Coadministration of dapsone with nitrates may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Ivacaftor: (Major) If dapsone and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Ivacaftor is a CYP3A substrate and dapsone is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold.
Lamivudine, 3TC; Zidovudine, ZDV: (Minor) Zidovudine, ZDV should be given with caution to patients also receiving dapsone due to the risk of additive hematologic toxicity.
Lesinurad: (Minor) The metabolism of dapsone may be accelerated when administered concurrently with lesinurad, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Lesinurad; Allopurinol: (Minor) The metabolism of dapsone may be accelerated when administered concurrently with lesinurad, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Letermovir: (Moderate) A clinically relevant increase in the plasma concentration of dapsone may occur if given with letermovir. In patients who are also receiving treatment with cyclosporine, the magnitude of this interaction may be amplified. Dapsone is a CYP3A4 substrate. Letermovir is a moderate CYP3A4 inhibitor; however, when given with cyclosporine, the combined effect on CYP3A4 substrates may be similar to a strong CYP3A4 inhibitor.
Lidocaine: (Moderate) Coadministration of dapsone with lidocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Lidocaine; Epinephrine: (Moderate) Coadministration of dapsone with lidocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Lidocaine; Prilocaine: (Moderate) Coadministration of dapsone with lidocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia. (Moderate) Coadministration of dapsone with prilocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Lopinavir; Ritonavir: (Moderate) Concurrent administration of dapsone with ritonavir may result in elevated dapsone plasma concentrations. Dapsone is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Lorlatinib: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with lorlatinib is necessary. Dapsone is a CYP3A4 substrate and lorlatinib is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Lumacaftor; Ivacaftor: (Major) If dapsone and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Ivacaftor is a CYP3A substrate and dapsone is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold.
Lumacaftor; Ivacaftor: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with lumacaftor; ivacaftor is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and lumacaftor; ivacaftor is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Mafenide: (Moderate) Coadministration of dapsone with sulfonamides may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Mavacamten: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with mavacamten is necessary. Dapsone is a CYP3A substrate and mavacamten is a moderate CYP3A inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Mepivacaine: (Moderate) Coadministration of dapsone with mepivacaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Methotrexate: (Major) Drugs with similar pharmacologic activity, such as dapsone, may lead to additive antifolate effects and bone marrow suppression when used with methotrexate.
Mitotane: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with mitotane is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and mitotane is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Modafinil: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with modafinil is necessary. Dapsone is a CYP3A4 substrate and modafinil is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Nafcillin: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with nafcillin is necessary. Dapsone is a CYP3A4 substrate and nafcillin is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Nilotinib: (Moderate) Concomitant use of nilotinib, a moderate CYP3A4 inhibitor, and dapsone, a CYP3A4 substrate, may result in increased dapsone levels. A dapsone dose reduction may be necessary if these drugs are used together.
Nirmatrelvir; Ritonavir: (Moderate) Concurrent administration of dapsone with ritonavir may result in elevated dapsone plasma concentrations. Dapsone is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Nitrates: (Moderate) Coadministration of dapsone with nitrates may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Nitrofurantoin: (Moderate) Coadministration of dapsone with nitrofurantoin may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Nitroglycerin: (Moderate) Coadministration of dapsone with nitrates may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Nitroprusside: (Moderate) Coadministration of dapsone with sodium nitroprusside may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Omeprazole; Amoxicillin; Rifabutin: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with rifabutin is necessary. Dapsone is a CYP3A4 substrate and rifabutin is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). In a study of 16 HIV-infected patients, rifabutin decreased dapsone exposure by 27% to 40%.
Pazopanib: (Moderate) Pazopanib is a weak inhibitor of CYP3A4. Coadministration of pazopanib and dapsone, a CYP3A4 substrate, may cause an increase in systemic concentrations of dapsone. Use caution when administering these drugs concomitantly.
Penicillin G Benzathine; Penicillin G Procaine: (Moderate) Coadministration of dapsone with penicillin G procaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Penicillin G Procaine: (Moderate) Coadministration of dapsone with penicillin G procaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Pexidartinib: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with pexidartinib is necessary. Dapsone is a CYP3A4 substrate and pexidartinib is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
Phenobarbital: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with phenobarbital is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and phenobarbital is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage. Also, coadministration of dapsone with phenobarbital may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with phenobarbital is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and phenobarbital is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage. Also, coadministration of dapsone with phenobarbital may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Phentermine; Topiramate: (Minor) The metabolism of dapsone may be accelerated when administered concurrently with topiramate, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Phenytoin: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with phenytoin is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and phenytoin is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage. Also, coadministration of dapsone with phenytoin may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Posaconazole: (Moderate) Posaconazole and dapsone should be coadministered with caution due to an increased potential for dapsone-related adverse events. Posaconazole is a potent inhibitor of CYP3A4, an isoenzyme responsible for the metabolism of dapsone. These drugs used in combination may result in elevated dapsone plasma concentrations, causing an increased risk for dapsone-related adverse events.
Prilocaine: (Moderate) Coadministration of dapsone with prilocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Prilocaine; Epinephrine: (Moderate) Coadministration of dapsone with prilocaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Primaquine: (Moderate) Coadministration of dapsone with primaquine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Primidone: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with primidone is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and primidone is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage. Also, coadministration of dapsone with primidone may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Probenecid: (Minor) Current evidence suggests that probenecid can inhibit the renal excretion of dapsone, resulting in elevated plasma concentrations. Dapsone toxicity as a result of this interaction has not been studied, so patients receiving these agents concurrently should be monitored for hemolytic anemia, methemoglobinemia, and/or peripheral neuropathy with muscle weakness. This interaction may, however, be beneficial in treating organisms that are resistant to dapsone.
Probenecid; Colchicine: (Minor) Current evidence suggests that probenecid can inhibit the renal excretion of dapsone, resulting in elevated plasma concentrations. Dapsone toxicity as a result of this interaction has not been studied, so patients receiving these agents concurrently should be monitored for hemolytic anemia, methemoglobinemia, and/or peripheral neuropathy with muscle weakness. This interaction may, however, be beneficial in treating organisms that are resistant to dapsone.
Pyrimethamine: (Major) Agranulocytosis has been reported in the second to third month of weekly concomitant treatment with dapsone and other hemolytic agents, such as pyrimethamine. This combination can increase the likelihood of adverse hematologic events.
Quinine: (Moderate) Coadministration of dapsone with quinine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Rifabutin: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with rifabutin is necessary. Dapsone is a CYP3A4 substrate and rifabutin is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). In a study of 16 HIV-infected patients, rifabutin decreased dapsone exposure by 27% to 40%.
Rifampin: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with rifampin is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and rifampin is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with rifampin decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Rifapentine: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with rifapentine is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and rifapentine is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Ritonavir: (Moderate) Concurrent administration of dapsone with ritonavir may result in elevated dapsone plasma concentrations. Dapsone is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Ropivacaine: (Moderate) Coadministration of dapsone with ropivacaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Rufinamide: (Minor) Rufinamide is not metabolized through hepatic CYP isozymes; however, it is a weak inducer of CYP3A4. In theory, decreased exposure of drugs that are extensively metabolized by CYP3A4, such as dapsone, may occur during concurrent use with rufinamide.
Saquinavir: (Major) Concurrent administration of oral dapsone and saquinavir boosted with ritonavir is not recommended, due to the potential for elevated dapsone concentrations and risk of dapsone-related side effects (i.e., hemolytic anemia, methemoglobinemia, or peripheral neuropathy). The metabolism of dapsone is mediated by CYP3A4, coadministration of drugs that inhibit CYP3A4, such as saquinavir boosted with ritonavir, may cause decreased clearance of dapsone.
Sotorasib: (Moderate) Closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia if coadministration with sotorasib is necessary. Dapsone is a CYP3A4 substrate and sotorasib is a moderate CYP3A4 inducer. Coadministration may decrease plasma concentrations of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis).
St. John's Wort, Hypericum perforatum: (Moderate) Monitor for an increase in hemolysis if coadministration of dapsone with St. John's Wort is necessary; dapsone efficacy may also be compromised. Dapsone is a CYP3A4 metabolite and St. John's Wort is a strong CYP3A4 inducer. Strong CYP3A4 inducers may increase the formation of dapsone hydroxylamine, a metabolite associated with hemolysis. Coadministration with another strong CYP3A4 inducer decreased dapsone levels by 7-fold to 10-fold; in leprosy, this reduction has not required a change in dosage.
Sulfadiazine: (Moderate) Coadministration of dapsone with sulfonamides may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Major) Agranulocytosis has been reported in the second to third month of weekly concomitant treatment with dapsone and other hemolytic agents such as folic acid antagonists (e.g., trimethoprim, sulfamethoxazole; trimethoprim, SMX-TMP, cotrimoxazole). These combinations increase the likelihood of adverse hematologic events. Concurrent administration of dapsone with trimethoprim increases the plasma concentrations of both drugs. The efficacy of dapsone is increased, which may provide a therapeutic advantage in the treatment of Pneumocystis pneumonia; however, an increase in the frequency and severity of dapsone toxicity (methemoglobinemia, hemolytic anemia) also has been noted. (Moderate) Coadministration of dapsone with sulfonamides may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Sulfasalazine: (Moderate) Coadministration of dapsone with sulfonamides may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Sulfonamides: (Moderate) Coadministration of dapsone with sulfonamides may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Tetracaine: (Moderate) Coadministration of dapsone with tetracaine may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Tezacaftor; Ivacaftor: (Major) If dapsone and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Ivacaftor is a CYP3A substrate and dapsone is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold.
Topiramate: (Minor) The metabolism of dapsone may be accelerated when administered concurrently with topiramate, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Tramadol; Acetaminophen: (Moderate) Coadministration of dapsone with acetaminophen may increase the risk of developing methemoglobinemia. Advise patients to discontinue treatment and seek immediate medical attention with any signs or symptoms of methemoglobinemia.
Tretinoin; Benzoyl Peroxide: (Minor) Coadministration of topical benzoyl peroxide-containing products with topical sulfone products, such as dapsone, may cause skin and facial hair to temporarily change color to a yellow/orange color.
Trimethoprim: (Major) Agranulocytosis has been reported in the second to third month of weekly concomitant treatment with dapsone and other hemolytic agents such as folic acid antagonists (e.g., trimethoprim, sulfamethoxazole; trimethoprim, SMX-TMP, cotrimoxazole). These combinations increase the likelihood of adverse hematologic events. Concurrent administration of dapsone with trimethoprim increases the plasma concentrations of both drugs. The efficacy of dapsone is increased, which may provide a therapeutic advantage in the treatment of Pneumocystis pneumonia; however, an increase in the frequency and severity of dapsone toxicity (methemoglobinemia, hemolytic anemia) also has been noted.
Valganciclovir: (Moderate) Use valganciclovir and dapsone together only if the potential benefits outweigh the risks; bone marrow suppression, spermatogenesis inhibition, skin toxicity, and gastrointestinal toxicity may be additive as both drugs inhibit rapidly dividing cells.
Vemurafenib: (Moderate) The metabolism of dapsone may be accelerated when administered concurrently with vemurafenib, a known inducer of CYP3A4. Coadministration is expected to decrease the plasma concentration of dapsone and increase the formation of dapsone hydroxylamine (a metabolite associated with hemolysis). If these drugs must be administered together, closely monitor for a reduction in dapsone efficacy and signs of hemolytic anemia.
Voriconazole: (Minor) Voriconazole is known inhibitor of isoenzyme CYP2C9 and theoretically may lead to increased concentrations of drugs that are substrates for this enzyme, including dapsone.
Zidovudine, ZDV: (Minor) Zidovudine, ZDV should be given with caution to patients also receiving dapsone due to the risk of additive hematologic toxicity.

Aczone/Dapsone Topical Gel: 5%, 7.5%
Dapsone Oral Tab: 25mg, 100mg

Leprosy, up to 100 mg/day PO; dermatitis herpetiformis, up to 300 mg/day PO; relapsing polychondritis, up to 200 mg/day PO; for acne topical use, 5% gel 2 applications/day topically or 7.5% gel 1 application/day topically.

Leprosy, up to 100 mg/day PO; dermatitis herpetiformis, up to 300 mg/day PO; relapsing polychondritis, up to 200 mg/day PO; for acne topical use, 5% gel 2 applications/day topically or 7.5% gel 1 application/day topically.

Leprosy, up to 100 mg/day PO; dermatitis herpetiformis, up to 300 mg/day PO; relapsing polychondritis, up to 200 mg/day PO; for acne topical use, 5% gel 2 applications/day topically or 7.5% gel 1 application/day topically.

12 years: Maximum oral dosage information not established; for acne topical use, 5% gel 2 applications/day topically or 7.5% gel 1 application/day topically.
9 to 11 years: Maximum oral dosage information not established; for acne topical use, 7.5% gel 1 application/day topically, safety and efficacy of 5% gel not established.
1 to 8 years: Maximum oral dosage information not established; safety and efficacy of topical gel not established.

Maximum oral dosage information not established; safety and efficacy of topical gel not established.

Safety and efficacy not established.

Similar to sulfonamides, dapsone inhibits dihyropteroate synthase in susceptible organisms. Other proposed mechanisms for dapsone include inhibition of the neutrophilic-cytotoxic system and interference with the alternate pathway of the complement system. Although the mechanism of dapsone in dermatologic disorders is unknown, it has been suggested that it may act as an immunomodulator.
 
For many years, dapsone was the main therapy for leprosy (Mycobacterium leprae). Unfortunately, years of monotherapy has lead to significant resistance in this organism. Resistance to M. leprae develops in 2—10% of patients after prolonged administration. Nevertheless, dapsone remains a component of combination therapy for leprosy.

Dapsone is administered orally or topically. It is widely distributed and is retained in the skin, muscles, kidneys, and liver. It also crosses the placenta and is distributed into breast milk.
 
Dapsone and its primary acetylated metabolite, monoacetyldapsone (MADDS), undergo enterohepatic recirculation. Acetylation is accomplished via N-acetyltransferase. Unlike with other acetylated compounds, slow and fast acetylators have exhibited no differences in pharmacokinetics, side effects, or therapeutic response. Minor metabolites include diacetyl derivatives and hydroxylamine dapsone (NOH-DDS). The latter metabolite appears to be associated with methemoglobinemia and hemolysis, which have been reported during therapy. The hydroxylamine metabolite is primarily produced by N-hydroxylation via CYP3A and CYP2C9 enzymes. The average half-life of both dapsone and MADDS is 30 hours. About 20% of a dose is excreted unchanged in the urine, while 70—85% is excreted as metabolites. A small amount can be detected in the feces.
 
Affected cytochrome P450 isoenzymes: CYP3A, CYP2C9

Dapsone is almost completely absorbed from the GI tract following oral administration. Peak serum levels are reached in 2—8 hours.

Following topical application, dapsone is absorbed into systemic circulation; however, systemic drug exposures are only 1% of those observed with the 100 mg oral dose. Steady state concentrations are achieved within 7 days of dosing.

Uncontrolled studies of systemic dapsone use in pregnant women have not demonstrated fetal risk during any trimester of pregnancy nor did use affect reproduction capacity. Although further study is needed, it has been recommended by some authorities that dapsone therapy be maintained during pregnancy in cases of leprosy or dermatitis herpetiformis. Information on the use of topical dapsone in pregnant patients is not available; however, systemic exposure of the topical gel is low compared to oral dapsone administration (approximately 100 times less).

Dapsone is distributed into breast milk in large quantities after oral dosing and can cause hemolytic anemia in nursing infants with G6PD deficiency. However, the American Academy of Pediatrics (AAP) states that dapsone is usually compatible with breast-feeding. Absorption after topical administration is minimal relative to oral dapsone administration. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, healthcare providers are encouraged to report the adverse effect to the FDA.