Intron A

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Intron A

Classes

Interferons for Hepatitis B and C
Interferons, Alpha

Administration

 
NOTE: Variations in dosage, routes of administration, and adverse reactions exist among different brands of interferon. Therefore, do not use different brands of interferon in any single treatment regimen.

Injectable Administration

Interferon alfa-2b may be administered intramuscularly, subcutaneously, intralesionally, or by intravenous infusion.
IMPORTANT: Interferon Alfa-2b (Intron A) is packaged as 1) powder for reconstitution/injection; 2) solution for injection in vials.
Not all dosage forms and strengths are appropriate for some indications (see below NOTES under each administration route). CAREFULLY read the instructions for the indication treated to ensure selection of an appropriate dosage form, strength, and route of administration.
Premedication with acetaminophen may decrease the incidence of administration-related reactions (i.e., fever). Bedtime administration may increase patient tolerance of therapy.
Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.
 
Solution for injection in vials:
Clear and colorless solution that does not require reconstitution before administration.
NOT recommended for intravenous administration.
Discard any unused solution for injection remaining in the multidose vial after 1 month.
 
Reconstitution of powder for injection:
Reconstitute Intron A powder vials, regardless of vial strength, with 1 mL sterile water for injection, USP (provided). The sterile water for injection, USP vial contains an excess amount of diluent (5 mL); the remaining diluent must be discarded. Do NOT use any diluent besides the one that is supplied, and do NOT add other medications to the reconstituted solution.
Swirl gently to aid in dissolution of the powder; do not shake.
Reconstituted interferon alfa-2b solution does not contain a preservative, and is intended for a single dose. Do not re-enter the vial after withdrawing the dose. Once the dose has been withdrawn from the vial, sterility can no longer be guaranteed. Discard the vial and unused portion after withdrawing the dose.
After reconstitution, the interferon alfa-2b solution is clear and colorless to light yellow and should be used immediately but may be stored at 2 to 8 degrees C (36 to 46 degrees F) for up to 24 hours.
For hairy cell leukemia: Reconstitute the 10 million international unit vials for a concentration of 10 million international unit/mL.
For condylomata acuminata: Reconstitute the 10 million international unit vials for a concentration of 10 million international unit/mL.
For AIDS-related Kaposi's Sarcoma: Reconstitute the 50 million international unit vials for a concentration of 50 million international unit/mL.
For malignant melanoma: Reconstitute the 10, 18, or 50 million international unit vials for concentrations of 10, 18, or 50 million international unit/mL, respectively.
For follicular lymphoma: Reconstitute the 10 million international unit vials for a concentration of 10 million international unit/mL.
For chronic hepatitis B: Reconstitute the 10 million international unit vials for a concentration of 10 million international unit/mL.

Intravenous Administration

Intravenous (IV) infusion:
For the induction phase of the adjuvant treatment of malignant melanoma: Use only the 10 million, 18 million, or 50 million international unit vials of Intron A powder for injection.
The appropriate dose of the reconstituted solution should be further diluted with 100 mL 0.9% Sodium Chloride injection.
The final concentration should not be less than 10 million international unit/100 mL.
The prepared solution should be infused over 20 minutes. The interferon alfa-2b infusion solution should be prepared immediately prior to use.

Intramuscular Administration

For Hairy Cell Leukemia: Use the 10 million international unit vials of Intron A powder for injection or the 18 or 25 million international unit vials of intron A solution for injection.
For AIDS-related Kaposi's sarcoma: Use the 50 million international unit vials of Intron A powder for injection.
For chronic hepatitis C: Use the 18 million international unit vials of Intron A solution for injection.
For chronic hepatitis B in adults: Use the 10 million international unit vials of Intron A powder for injection or the 25 million international unit vials of Intron A solution for injection.
Inject interferon alfa-2b deeply into a large muscle. Aspirate prior to injection to avoid injection into a blood vessel.

Subcutaneous Administration

For the maintenance phase of the adjuvant treatment of malignant melanoma: Use the 10 or 18 million international unit vials of Intron A powder for injection; the 18 or 25 million international unit vials of Intron A solution for injection. The 10 million international unit vials of Intron A powder for injection is only for patients who get a 50% reduced dose, and the 18 million international unit vials of Intron A powder for injection are only for patients who get the full dose.
For Hairy Cell Leukemia: Use the 10 million international unit vials of Intron A powder for injection or the 18 or 25 million international unit vials of intron A solution for injection.
For follicular lymphoma: Use the 10 million international unit vials of Intron A powder for injection or the 18 or 25 million international unit vials of Intron A solution for injection.
For AIDS-related Kaposi's sarcoma: Use only the 50 million international unit vials of Intron A powder for injection.
For chronic hepatitis C: Use the 18 million international unit vials of Intron A solution for injection.
For chronic hepatitis B in adults: Use the 10 million international unit vials of Intron A powder for injection or the 25 million international unit vials of Intron A solution for injection.
For chronic hepatitis B in children: Use the 10 million international unit vials of Intron A powder for injection or the 25 million international unit vials of Intron A solution for injection.
Inject interferon alfa-2b subcutaneously taking care not to inject intradermally.

Other Injectable Administration

Intralesional Administration
For condylomata acuminata: Use only the 10 million international unit vials of Intron A powder for injection or the 25 million international unit vials of Intron A solution for injection, each having a final concentration of 10 million international unit/ml.
Use a Tuberculin or similar syringe and a 25- to 30-gauge needle.
The needle should be directed at the center base of the wart and at an angle almost parallel to the plane of the skin. This will deliver the interferon to the dermal core of the lesion, infiltrating the lesion and causing a small wheal.
Do not go beneath the lesion too deeply; avoid subcutaneous injection. Do not inject too superficially because infiltration of only the keratinized layer and not the dermal core will occur and leakage may occur.

Adverse Reactions
Severe

bronchospasm / Rapid / 0-5.0
hemolytic anemia / Delayed / 0-5.0
suicidal ideation / Delayed / 1.0-3.0
seizures / Delayed / 2.0
cardiomyopathy / Delayed / 2.0
coma / Early / Incidence not known
GI bleeding / Delayed / Incidence not known
pancreatitis / Delayed / Incidence not known
hepatic failure / Delayed / Incidence not known
myocardial infarction / Delayed / Incidence not known
pericarditis / Delayed / Incidence not known
pulmonary fibrosis / Delayed / Incidence not known
pulmonary hypertension / Delayed / Incidence not known
stroke / Early / Incidence not known
aplastic anemia / Delayed / Incidence not known
red cell aplasia / Delayed / Incidence not known
vasculitis / Delayed / Incidence not known
autoimmune disease / Delayed / Incidence not known
lupus-like symptoms / Delayed / Incidence not known
rhabdomyolysis / Delayed / Incidence not known
non-arteritic anterior ischemic optic neuropathy / Delayed / Incidence not known
retinopathy / Delayed / Incidence not known
visual impairment / Early / Incidence not known
retinal hemorrhage / Delayed / Incidence not known
optic neuritis / Delayed / Incidence not known
papilledema / Delayed / Incidence not known
retinal thrombosis / Delayed / Incidence not known
macular edema / Delayed / Incidence not known

Moderate

depression / Delayed / 3.0-40.0
dyspnea / Early / 0-34.0
neutropenia / Delayed / 0-34.0
anemia / Delayed / 0-27.0
thrombocytopenia / Delayed / 0-10.0
confusion / Early / 1.0-8.0
psychosis / Early / 0-5.0
hot flashes / Early / 0-5.0
leukopenia / Delayed / 0-5.0
hallucinations / Early / Incidence not known
hostility / Early / Incidence not known
encephalopathy / Delayed / Incidence not known
ascites / Delayed / Incidence not known
hyperbilirubinemia / Delayed / Incidence not known
growth inhibition / Delayed / Incidence not known
hypertriglyceridemia / Delayed / Incidence not known
elevated hepatic enzymes / Delayed / Incidence not known
colitis / Delayed / Incidence not known
supraventricular tachycardia (SVT) / Early / Incidence not known
hypertension / Early / Incidence not known
angina / Early / Incidence not known
sinus tachycardia / Rapid / Incidence not known
chest pain (unspecified) / Early / Incidence not known
hypotension / Rapid / Incidence not known
pneumonitis / Delayed / Incidence not known
psoriasis / Delayed / Incidence not known

Mild

fatigue / Early / 8.0-96.0
fever / Early / 34.0-94.0
myalgia / Early / 16.0-75.0
anorexia / Delayed / 1.0-69.0
nausea / Early / 18.0-66.0
asthenia / Delayed / 5.0-63.0
headache / Early / 21.0-62.0
chills / Rapid / 45.0-54.0
dizziness / Early / 7.0-50.0
musculoskeletal pain / Early / 1.0-50.0
diarrhea / Early / 2.0-50.0
abdominal pain / Early / 1.0-50.0
dysgeusia / Early / 0-50.0
weight loss / Delayed / 0-50.0
vomiting / Early / 2.0-50.0
alopecia / Delayed / 0-50.0
pharyngitis / Delayed / 1.0-50.0
xerostomia / Early / 1.0-28.0
paresthesias / Delayed / 0-21.0
diaphoresis / Early / 1.0-21.0
sinusitis / Delayed / 1.0-21.0
arthralgia / Delayed / 3.0-19.0
malaise / Early / 3.0-14.0
cough / Delayed / 0-13.0
insomnia / Early / 0-12.0
nasal congestion / Early / 0-10.0
anxiety / Delayed / 0-9.0
emotional lability / Early / 0-5.0
tongue discoloration / Delayed / Incidence not known
injection site reaction / Rapid / Incidence not known
pruritus / Rapid / Incidence not known
back pain / Delayed / Incidence not known
xerosis / Delayed / Incidence not known
purpura / Delayed / Incidence not known
infection / Delayed / Incidence not known

Boxed Warning
Alcoholism, depression, driving or operating machinery, psychiatric event, seizure disorder, substance abuse, suicidal ideation

Development or exacerbation of a fatal or life-threatening neuro-psychiatric event (e.g., depression, suicidal ideation, suicide attempts, completed suicides, homicidal ideation, and aggression towards others) has been observed in patients receiving alpha interferons. Patients with pre-existing history of depression or severe psychiatric disorder may be at increased risk; thus, interferon therapy must be administered with extreme caution to these patients. In addition, pediatric drug recipients (primarily adolescents) are more likely to experience suicidal ideation or attempts as compared to adults (2.4% vs. 1%). Caution is also advised for patients with history of substance abuse (e.g., alcoholism), as relapse and drug overdose may occur. Instruct all patients to immediately report any symptoms of depression or suicidal ideation to their health care provider. Closely monitor patients for depression and other psychiatric symptoms during treatment and for 6 months after the last alfa interferon dose. For patients who experience persistent or worsening psychiatric symptoms, immediately discontinue interferon alfa-2b treatment. Although, dose reduction or cessation of therapy may lead to resolution of the symptoms, depression may persist and suicides have occurred after withdrawing therapy. Full resolution of symptoms may take up to 3 weeks in severe cases. Any patient with a seizure disorder or compromised nervous system function should receive interferon alfa-2b with caution. Central nervous system toxicities have occurred. Patients should be warned against driving or operating machinery until they know how interferon alfa-2b therapy will affect them.

Stroke, thrombophlebitis

Development or exacerbation of fatal or life-threatening ischemic disorders has been observed in patients receiving alpha interferons. Ischemic and hemorrhagic cerebrovascular events have been observed in patients treated with interferon alfa-2b; some patients had few or no reported risk factors for stroke. Caution should be observed in patients with coagulation disorders (eg, thrombophlebitis, pulmonary embolism). Patients should be monitored closely with periodic clinical and laboratory evaluations. Interferon alfa-2b should be discontinued in patients with persistently severe or worsening signs or symptoms of ischemic conditions. In many but not all cases, these disorders resolve after stopping interferon alfa-2b.

Anemia, angina, cardiac arrhythmias, cardiac disease, chronic obstructive pulmonary disease (COPD), heart failure, myocardial infarction, neoplastic disease, pulmonary disease, use with ribavirin

Interferon alfa-2b should be used cautiously in patients with debilitating conditions such as those with a history of cardiac disease (e.g., angina or congestive heart failure) or pulmonary disease (e.g., chronic obstructive pulmonary disease (COPD)) because of fever and flu-like symptoms associated with interferon alfa-2b. Patients with a history of myocardial infarction and/or previous or current cardiac arrhythmias who require interferon alfa-2b therapy should be closely monitored. Supraventricular tachycardia appears to be correlated with preexisting conditions or previous treatment with cardiotoxic agents. Patients with preexisting cardiac abnormalities and/or advanced stage neoplastic disease should have electrocardiograms taken before and during the course of treatment. Patients who develop persistent or unexplained pulmonary infiltrates or pulmonary function impairment should be closely monitored; discontinue interferon alfa-2b, if appropriate. Use with ribavirin: Interferon alfa-2b may be used with ribavirin, and ribavirin causes hemolytic anemia. Hemoglobin < 10 g/dL was observed in approximately 10% of adult and pediatric patients in clinical trials. Anemia occurred within 1—2 weeks of ribavirin initiation. Anemia may worsen cardiac disease. Ribavirin is not recommended for patients with a history of significant or unstable cardiac disease, and do not administer combination treatment with interferon alfa-2b and ribavirin to patients with creatinine clearance < 50 mL/minute. Do not use ribavirin in pregnant patients, as the drug may also cause birth defects or fetal death.

Autoimmune disease, psoriasis, rheumatoid arthritis, systemic lupus erythematosus (SLE), thrombocytopenia

Interferon alfa-2b should be used with caution in patients with a history of autoimmune disease and only if the potential benefit justifies the risk; patients with chronic hepatitis B or C and a history of autoimmune disease should not be treated with interferon alfa-2b because of reports of worsening liver disease including jaundice, hepatic encephalopathy, hepatic failure, and death after interferon alfa-2b in such patients. Interferon alfa-2b is contraindicated for use in patients with autoimmune hepatitis. Development or exacerbation of fatal or life-threatening autoimmune diseases (e.g., thyroiditis, thrombocytopenia, rheumatoid arthritis, interstitial nephritis, systemic lupus erythematosus (SLE), sarcoidosis, or psoriasis) has been observed in patients receiving interferon alfa-2b. Patients should be monitored closely with periodic clinical and laboratory evaluations. Interferon alfa-2b should be discontinued in patients with persistently severe or worsening signs or symptoms of these conditions. In many but not all cases, these disorders resolve after stopping interferon alfa-2b.

Infection, neutropenia

Development or exacerbation of fatal or life-threatening infectious disorders has been observed in patients receiving alpha interferons. Serious and severe bacterial infections, some fatal and some not associated with neutropenia, have been observed in patients treated with alpha interferons. Patients should be monitored closely with baseline and periodic clinical and laboratory evaluations. Interferon alfa-2b should be discontinued in patients with persistently severe or worsening signs or symptoms of infectious processes. In many but not all cases, these disorders resolve after stopping interferon alfa-2b.

Common Brand Names

Intron A

Dea Class

Rx

Description

Recombinant alpha interferon; represents only one specific subtype of alpha interferon; used in hairy cell leukemia, melanoma, NHL, genital warts, Kaposi's sarcoma, chronic hepatitis C and B.

Dosage And Indications
For the treatment of hairy-cell leukemia. Subcutaneous or Intramuscular dosage

NOTE: Administer interferon alfa-2b subcutaneously as opposed to intramuscularly if the patient's platelet counts is less than 50,000/mm3.

Adults

2 million International Units/m2 IM or subcutaneously 3 times a week for up to 6 months. Higher doses are not recommended. Therapeutic benefit may not be seen for 2 months. Responding patients may benefit from continued treatment. If severe adverse reactions occur, the dosage should be reduced by 50% or temporarily discontinued until symptoms resolve, and resume dose at 1 million International Units/m2 IM or subcutaneously 3 times a week. If persistent or recurrent intolerance develops following adequate dosage adjustment or disease progresses, treatment should be permanently discontinued. The minimum effective dose has not been established.

For the adjuvant treatment of malignant melanoma in patients who are disease free and at high risk for systemic recurrence within 56 days of surgery. Intravenous or Subcutaneous dosage

NOTE: Intron A Solution for Injection in vials is NOT recommended for intravenous administration and should not be used for the induction phase treatment of melanoma.

Adults

20 million international Units/m2 IV infusion for 5 consecutive days per week for 4 weeks as induction therapy followed by 10 million International Units/m2 subcutaneously 3 times per week for 48 weeks. Monitor white blood cell count and liver function tests weekly during induction and monthly during maintenance therapy. If the absolute neutrophil count (ANC) decreases to less than 500/mm3 or serum transaminases increase to 5 times the upper limit of normal, therapy should be held until values normalize. Therapy should be restarted at 50% of the previous dose. If toxicity does not abate after withholding interferon alfa-2b, if intolerance continues after dose adjustments, or if the ANC decreases to less than 250/mm3 or transaminases increase to more than 10 times the upper limit of normal, interferon alfa-2b therapy should be permanently discontinued.

For the treatment of aggressive, follicular non-Hodgkin's lymphoma (NHL) in conjunction with an anthracycline-containing combination chemotherapy regimen. Subcutaneous dosage Adults

5 million International Units subcutaneously 3 times per week for up to 18 months in combination with an anthracycline-containing combination chemotherapy regimen and following completion of the chemotherapy regimen. In published reports, the doses of myelosuppressive drugs were reduced 25% from those utilized in the full-dose CHOP regimen, and the cycle length was increased from 21 to 28 days when alfa interferon was added. The following dose adjustments are recommended: For absolute neutrophil count (ANC) less than 1500/mm3 or platelet count less than 75,000/mm3, the chemotherapy regimen was delayed. For an ANC less than 1000/mm3 or platelet count less than 50,000/mm3, interferon alfa-2b treatment was held. For ANC more than 1000/mm3 but less than 1500/mm3, reduce the dose by 50% to a dose of 2.5 million International Units subcutaneously 3 times per week. The initial dose may be restarted once the ANC is more than 1500/mm3. Interferon alfa-2b therapy should be permanently discontinued if the SGOT exceeds 5 times the upper limit of normal or if the serum creatinine is more than 2 mg/dL.

For the treatment of condylomata acuminata (genital or venereal warts), due to the human papillomavirus (HPV) infection, involving the external surfaces of the genital and perianal areas. Intralesional dosage

NOTE: Use only the 10 million International Unit vials of Intron A powder for injection or the 25 million International Unit strengths of Intron A solution for injection, each having a final concentration of 10 million International Units/mL. Other Intron A formulations should not be used because the concentrations or tonicity may be inappropriate.

Adults

Inject 1 million International Units (0.1 mL) into each lesion 3 times per week on alternating days for 3 weeks. A maximum of 5 warts should be treated per course. An additional course may be administered at 12 to 16 weeks. The HIV guidelines generally do not recommend due to cost, administration difficulties, and systemic side effects.

For the treatment of AIDS-related Kaposi's sarcoma.
NOTE: Interferon alfa-2b should not be used for the treatment of visceral AIDS-related Kaposi's sarcoma associated with rapidly progressive disease.
NOTE: Interferon alfa-2b has been designated an orphan drug by the FDA for this indication.
Subcutaneous or Intramuscular dosage

NOTE: Intron A Solution for Injection in vials should NOT be used for the treatment of AIDS-related Kaposi's sarcoma.

Adults

The recommended dose is 30 million International Units/m2 IM or subcutaneously 3 times per week until disease progression or achievement of maximal response after 16 weeks of treatment. Dose reduction by 50% or drug suspension is needed for severe adverse reactions. If severe reactions abate with dosing interruption, resume interferon alfa-2b at a reduced dose. Permanently discontinue interferon alfa-2b if severe reactions persist or if they recur at a reduced dose. The average tolerated dose at the end of 12 weeks is 110 million International Unit/week and 75 million International Unit/week after 24 weeks. The likelihood of response to interferon alfa-2b therapy is greater in patients without systemic symptoms, who have limited lymphadenopathy, and who have a relatively intact immune system, as indicated by total CD4 count.

For the treatment of chronic hepatitis B infection in patients with compensated liver disease.
NOTE: Patients who have been serum HBsAg positive for at least 6 months and have evidence of HBV replication (serum HBeAg positive) with elevated serum ALT are candidates for treatment.
NOTE: Evaluate liver function tests, HBeAg, and HBsAg before treatment initiation, at therapy cessation, and at both 3 and 6 months after therapy cessation. In clinical studies, 15 of 38 responding adults lost HBeAg 1 to 6 months after interferon alfa-2b cessation. Further, 7 of 12 responding adults lost HBsAg 1 to 6 months after interferon alfa-2b cessation.
Subcutaneous or Intramuscular dosage

NOTE: Only the 25 million International Unit/dose Intron A Solution for Injection or the 10 million International Unit Powder for Injection should be used.

Adults

30 to 35 million International Units per week IM or subcutaneously for 16 weeks administered, either as 5 million International Units per day or as 10 million International Units 3 times per week. Dose reduction by 50% or drug suspension is needed for severe adverse reactions. If severe reactions abate with dosing interruption, resume interferon alfa-2b at a reduced dose. Discontinue interferon alfa-2b if severe reactions recur at a reduced dose. During therapy with interferon alfa-2b, if white blood cell counts, granulocyte counts, or platelet counts fall below 1500/mm3, 750/mm3, or 50,000/mm3, respectively, the dose should be reduced by 50%. If counts fall below 1000/mm3, 500/mm3, or 25,000/mm3, respectively, therapy should be permanently discontinued. Interferon alfa-2b may be restarted at up to 100% of initial dose when blood cell counts return to normal or baseline levels.

Subcutaneous dosage

NOTE: Only the 25 million International Unit/dose Intron A Solution for Injection or the 10 million International Unit Powder for Injection should be used.

Children and Adolescents

3 million International Units/m2 subcutaneously 3 times per week for the first week of therapy, then escalated to 6 million International Units/m2 (maximum 10 million International Units) subcutaneously 3 times per week for 16 to 24 weeks. Dose reduction by 50% or drug suspension is needed for severe adverse reactions. If severe reactions abate with dosing interruption, resume interferon alfa-2b at a reduced dose. Discontinue interferon alfa-2b if severe reactions recur at a reduced dose. During therapy with interferon alfa-2b, if white blood cell counts, granulocyte counts, or platelet counts fall below 1500/mm3, 750/mm3, or 50,000/mm3, respectively, the dose should be reduced by 50%. Interferon alfa-2b may be restarted at up to 100% of initial dose when blood counts return to normal or baseline levels. If the white blood cell count falls below 1000/mm3, the granulocyte count falls below 500/mm3, or the platelet count falls below 25,000/mm3, permanently discontinue interferon alfa-2b.

For the treatment of hepatitis C infection in patients with compensated liver disease. In patients with a blood or blood-product exposure history or HCV antibody positivity.
NOTE: Establish the diagnosis by liver biopsy.
Subcutaneous or Intramuscular dosage

NOTE: Only the 18 million International Unit/dose Intron A Solution for Injection should be used.

Adults

3 million International Units administered IM or subcutaneously 3 times per week should be continued for up to 18 to 24 months if a positive response (i.e., normalization of ALT values) is seen at 16 weeks of therapy. If no response is seen at 16 weeks of therapy, consider discontinuing therapy. If severe adverse reactions develop during therapy, the interferon alfa-2b dosage should be modified (50% reduction) or treatment held until symptoms resolve. If intolerance persists after dose adjustment, therapy should be discontinued.

In combination with ribavirin in patients previously untreated with interferon alpha. Subcutaneous or Intramuscular dosage Adults

3 million International Units IM or subcutaneously 3 times per week plus daily ribavirin. The recommended duration of treatment is 24 to 48 weeks for adults; consider treatment discontinuation if an HCV-RNA value below the level of detection has not been achieved at 24 weeks. There are no safety or efficacy data on treatment longer than 48 weeks.

Children and Adolescents older than 3 years and weighing more than 61 kg

3 million International Units IM or subcutaneously 3 times per week plus daily ribavirin. The duration of treatment for genotype 1 is 48 weeks; consider treatment discontinuation if an HCV-RNA value below the level of detection has not been achieved at 24 weeks. The duration of treatment for genotype 2 or 3 is 24 weeks. NOTE: Consider response prognostic factors, HCV genotype, viral load, and disease progression evidence such as hepatic inflammation and fibrosis when deciding to treat a pediatric patient. Weigh treatment benefits against safety findings from the clinical trials.

Children and Adolescents older than 3 years and weighing 25 to 61 kg

3 million International Units/m2 subcutaneously 3 times per week plus daily ribavirin. The duration of treatment for genotype 1 is 48 weeks; consider treatment discontinuation if an HCV-RNA value below the level of detection has not been achieved at 24 weeks. The duration of treatment for genotype 2 or 3 is 24 weeks. NOTE: Consider response prognostic factors, HCV genotype, viral load, and disease progression evidence such as hepatic inflammation and fibrosis when deciding to treat a pediatric patient. Weigh treatment benefits against safety findings from the clinical trials.

In combination with ribavirin in patients who have relapsed following interferon alpha therapy. Subcutaneous or Intramuscular dosage Adults

3 million International Units IM or subcutaneously 3 times per week plus daily ribavirin for 24 weeks in adults; consider treatment discontinuation if an HCV-RNA value below the level of detection has not been achieved at 24 weeks. There are no safety or efficacy data on treatment longer than 24 weeks.

Children and Adolescents older than 3 years and weighing more than 61 kg

3 million International Units IM or subcutaneously 3 times per week plus daily ribavirin. The duration of treatment for genotype 1 is 48 weeks; consider treatment discontinuation if an HCV-RNA value below the level of detection has not been achieved at 24 weeks. The duration of treatment for genotype 2 or 3 is 24 weeks. NOTE: Consider response prognostic factors, HCV genotype, viral load, and disease progression evidence such as hepatic inflammation and fibrosis when deciding to treat a pediatric patient. Weigh treatment benefits against safety findings from the clinical trials.

Children and Adolescents older than 3 years and weighing 25 to 61 kg

3 million International Units subcutaneously 3 times per week plus daily ribavirin. The duration of treatment for genotype 1 is 48 weeks; consider treatment discontinuation if an HCV-RNA value below the level of detection has not been achieved at 24 weeks. The duration of treatment for genotype 2 or 3 is 24 weeks. NOTE: Consider response prognostic factors, HCV genotype, viral load, and disease progression evidence such as hepatic inflammation and fibrosis when deciding to treat a pediatric patient. Weigh treatment benefits against safety findings from the clinical trials.

For the treatment of West Nile virus infection† (i.e., symptomatic flavivirus infections).
NOTE: Other than supportive care, there is no established treatment for symptomatic flavivirus infections. The use of interferon alfa-2b for the treatment of West Nile virus is suggested by in vitro data only.
Subcutaneous dosage Adults

In the US, a government-supported national trial has been initiated to study the use of alpha-interferon for West Nile infection (press-release, August 26, 2002); a regimen of interferon alfa-2b therapy for 2 weeks will be used for the treatment of infected hospitalized patients 50 years of age and older. In an in vitro study, interferon alfa-2b at low doses was protective and therapeutic against West Nile virus infection. In humans, daily doses of 3 million International units subcutaneously result in serum concentrations well above those required for in vitro efficacy against West Nile virus.

For the treatment of St. Louis encephalitis† (i.e., symptomatic flavivirus infections). Subcutaneous dosage Adults

For the treatment of St. Louis encephalitis, interferon alfa-2b 6 million International Units subcutaneously on day 1, then 3 million International Units subcutaneously once daily for a total 14 days was studied in 15 patients. The increase in mean neurologic score was significantly higher in treated patients from week 0 to 3 and 0 to 4 as compared to untreated controls. Among the 17 untreated patients, 3 developed quadriplegia and ventilator dependence after admission, while no patient treated with interferon alfa-2b developed these complications.

For the first-line treatment of Philadelphia chromosome positive, chronic phase, chronic myelogenous leukemia (CML)†, in combination with cytarabine. Subcutaneous dosage Adults less than 72 years, Adolescents, and Children older than 7 years

5 million International Units/m2/day subcutaneously as continuous therapy plus cytarabine 20 mg/m2/day subcutaneously for 10 days each month (median duration of therapy, 34 months) was evaluated in a large randomized trial. Cytarabine therapy was initiated 2 weeks after interferon therapy had begun. All patients also received hydroxyurea 50 mg/kg/day (or less depending on white blood cell count) until a complete hematologic remission was achieved.

For the treatment of renal cell cancer† in combination with bevacizumab for previously untreated metastatic disease.
NOTE: Bevacizumab is FDA-approved for this indication.
Subcutaneous dosage Adults

9 million International Units subcutaneously 3 times weekly in combination with bevacizumab (10 mg/kg IV every 2 weeks). In a phase III trial of 710 patients with previously untreated metastatic renal cell carcinoma, median progression-free survival was significantly longer with interferon alfa-2b plus bevacizumab versus interferon alfa-2b therapy alone (8.5 months vs. 5.2 months). Grade 3 toxicities that were significantly greater in the bevacizumab arm include hypertension, anorexia, fatigue, and proteinuria. Results for the primary endpoint, overall survival, have not yet been released for this trial.

For the maintenance treatment for multiple myeloma†. Subcutaneous dosage Adults

3 million International Units/dose or 3 million International Units/m2/dose subcutaneously 3 times weekly as maintenance therapy in patients who respond to standard therapy for multiple myeloma has been studied in randomized clinical studies.

For the treatment of hypereosinophilic syndrome†. Subcutaneous dosage Adults

Six patients with hypereosinophilic syndrome were given 1 to 6.25 million International Units/day subcutaneously in a phase I trial. A satisfactory response was noted in 5 patients.

For the treatment of hemangioma† of infancy or pulmonary hemangiomatosis†. Subcutaneous dosage Infants and Children

1 to 3 million International Units/m2/day subcutaneously once daily.

For the treatment of adult T-cell leukemia/lymphoma† in combination with zidovudine in patients infected with human T-lymphotropic virus type I (HTLV-I). Subcutaneous dosage Adults

In a small study, the combination of interferon alfa-2b 5 million International Units subcutaneously once daily for the first week with the dose escalated to 10 million International Units subcutaneously once daily after 1 week, if tolerated, with oral zidovudine produced major responses in 11 of 19 patients (58%), including complete remissions in 5 of 19 (26%). Doses were adjusted for hematologic toxicity. Treatment was continued for at least 4 weeks after the onset of complete remission, or, for up to 1 year in the absence of remission.

†Indicates off-label use

Dosing Considerations
Hepatic Impairment

Avoid use in patients with severe hepatic injury (Grade 3) or hepatic decompensation (Child-Pugh score > 6; Class B and C). Interferon alfa-2b has not been studied in patients with decompensated hepatic disease.

Renal Impairment

Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed. However, close monitoring of patients with impaired renal function is warranted, as interferon alfa-2b is substantially excreted by the kidney. Alfa interferons are not cleared by hemodialysis.

Drug Interactions

Abacavir: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Abacavir; Dolutegravir; Lamivudine: (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6). (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Abacavir; Lamivudine, 3TC: (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6). (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Abacavir; Lamivudine, 3TC; Zidovudine, ZDV: (Major) Use interferons and zidovudine together with caution. Closely monitor patients for treatment-associated toxicities, especially hematologic effects and hepatic decompensation, and manage as recommended for the individual therapies. Coadministration of alpha interferons may increase the hematologic toxicity of zidovudine. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) are also associated with hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. Interferon therapy may also reduce zidovudine clearance. (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6). (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Aldesleukin, IL-2: (Moderate) Myocardial injury, exacerbation or the initial presentation of autoimmune and inflammatory disorders, and hypersensitivity reactions appear to be increased in patients receiving aldesleukin, IL-2 and alpha interferons concurrently.
Alemtuzumab: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Alteplase: (Moderate) An increased risk of bleeding may occur when thrombolytic agents are used following agents that cause clinically significant thrombocytopenia including antineoplastic agents.
Altretamine: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Arsenic Trioxide: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Atazanavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Atazanavir; Cobicistat: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Azathioprine: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Bacillus Calmette-Guerin Vaccine, BCG: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Basiliximab: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Cabotegravir; Rilpivirine: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and rilpivirine can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving antiretroviral agents and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Chloroquine: (Moderate) Concurrent use of chloroquine and interferons is not recommended as there is an increased risk of retinal toxicity.
Clozapine: (Major) It is unclear if concurrent use of other drugs known to cause neutropenia (e.g., certain antineoplastic agents) increases the risk or severity of clozapine-induced neutropenia. Because there is no strong rationale for avoiding clozapine in patients treated with these drugs, consider increased absolute neutrophil count (ANC) monitoring and consult the treating oncologist.
Corticosteroids: (Minor) Because systemically administered corticosteroids exhibit immunosuppressive effects when given in high doses and/or for extended periods, additive effects may be seen with other immunosuppressives or antineoplastic agents.
Darunavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Darunavir; Cobicistat: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART. (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Delavirdine: (Major) The concomitant use of interferons and anti-retroviral non-nucleoside reverse transcriptase inhibitors (NNRTIs) should be done with caution as both can cause hepatic damage. NNRTIs may cause liver damage in the context of hypersensitivity reactions or by direct toxic effects. Many studies demonstrate that nevirapine is more hepatotoxic than efavirenz. Underlying chronic HCV infection enhances the risk of developing liver enzyme elevations in patients receiving nevirapine. Overall, the HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation.
Digoxin: (Moderate) Some antineoplastic agents have been reported to decrease the absorption of digoxin tablets due to their adverse effects on the GI mucosa; the effect on digoxin liquid is not known. The reduction in digoxin tablet absorption has resulted in plasma concentrations that are 50% of pretreatment levels and has been clinically significant in some patients. It is prudent to closely monitor patients for loss of clinical efficacy of digoxin while receiving antineoplastic therapy.
Dolutegravir; Lamivudine: (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6).
Dolutegravir; Rilpivirine: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and rilpivirine can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving antiretroviral agents and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6).
Efavirenz: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and efavirenz can both cause hepatotoxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and efavirenz can both cause hepatotoxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6). (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and efavirenz can both cause hepatotoxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Emtricitabine: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and rilpivirine can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving antiretroviral agents and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Emtricitabine; Rilpivirine; Tenofovir Disoproxil Fumarate: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and rilpivirine can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving antiretroviral agents and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Emtricitabine; Tenofovir alafenamide: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Entecavir: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Estramustine: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Ethanol: (Major) Consider the potential risk of interferon alfa products used in combination with known hepatotoxic drugs or other products (e.g., alcohol) prior to use. Monitor hepatic function during interferon beta treatment. Patients should be advised to avoid drinking alcohol to reduce the chance of injury to the liver during interferon alfa treatment. Alcohol may also potentiate drowsiness and dizziness. Patients who develop dizziness, confusion, somnolence, and fatigue with interferon alfa treatment should be cautioned to avoid driving or operating machinery.
Filgrastim, G-CSF: (Major) Filgrastim induces the proliferation of neutrophil-progenitor cells, and, because antineoplastic agents exert toxic effects against rapidly growing cells, filgrastim is contraindicated for use during the 24 hours before or after cytotoxic chemotherapy.
Fluorouracil, 5-FU: (Minor) Interferon alfa-2b has been studied extensively in clinical trials with systemic fluorouracil, 5-FU. It has been shown in vitro that the addition of alfa interferon to 5-FU increases single-strand and double-strand DNA breaks and increases natural killer cell-mediated cytotoxicity. However, in clinical trials the addition of alfa interferons to 5-FU therapy resulted in an increased incidence of adverse effects with no increase in response rate versus 5-FU alone.
Folate analogs: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Fosamprenavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Hydroxyurea: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Ibritumomab Tiuxetan: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Imatinib: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Indinavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Intranasal Influenza Vaccine: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Lamivudine, 3TC: (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6).
Lamivudine, 3TC; Zidovudine, ZDV: (Major) Use interferons and zidovudine together with caution. Closely monitor patients for treatment-associated toxicities, especially hematologic effects and hepatic decompensation, and manage as recommended for the individual therapies. Coadministration of alpha interferons may increase the hematologic toxicity of zidovudine. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) are also associated with hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. Interferon therapy may also reduce zidovudine clearance. (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6).
Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Monitor for treatment-associated toxicities, especially hepatic decompensation, during coadministration of interferons (with or without ribavirin) and lamivudine. Dose reduction or discontinuation of interferon, ribavirin, or both should be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6).
Live Vaccines: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Lomustine, CCNU: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Lopinavir; Ritonavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Measles Virus; Mumps Virus; Rubella Virus; Varicella Virus Vaccine, Live: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Measles/Mumps/Rubella Vaccines, MMR: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Methotrexate: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Methoxsalen: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Mitoxantrone: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Nelfinavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Nevirapine: (Major) The concomitant use of interferons and nevirapine should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Nevirapine may cause liver damage in the context of hypersensitivity reactions or by direct toxic effects. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. Patients with signs or symptoms of hepatitis, or with increased transaminases combined with rash or other systemic symptoms, must discontinue nevirapine and seek medical evaluation immediately.
Nirmatrelvir; Ritonavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Pegfilgrastim: (Major) Pegfilgrastim induces the proliferation of neutrophil-progenitor cells, and because antineoplastic agents exert toxic effects against rapidly growing cells, pegfilgrastim should not be given 14 days before or for 24 hours after cytotoxic chemotherapy.
Pemetrexed: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Pexidartinib: (Moderate) Monitor for evidence of hepatotoxicity if pexidartinib is coadministered with interferon alfa. Avoid concurrent use in patients with increased serum transaminases, total bilirubin, or direct bilirubin (more than ULN) or active liver or biliary tract disease.
Pralatrexate: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Pretomanid: (Major) Avoid coadministration of pretomanid with interferon alfa, especially in patients with impaired hepatic function, due to increased risk for hepatotoxicity. Monitor for evidence of hepatotoxicity if coadministration is necessary. If new or worsening hepatic dysfunction occurs, discontinue hepatotoxic medications.
Protease inhibitors: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Purine analogs: (Moderate) Additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Reteplase, r-PA: (Moderate) An increased risk of bleeding may occur when thrombolytic agents are used following agents that cause clinically significant thrombocytopenia including antineoplastic agents.
Rilpivirine: (Moderate) Use together with caution and monitor for hepatic decompensation. Interferons and rilpivirine can both cause hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving antiretroviral agents and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART.
Riluzole: (Moderate) Monitor for signs and symptoms of hepatic injury during coadministration of riluzole and interferon alfa. Concomitant use may increase the risk for hepatotoxicity. Discontinue riluzole if clinical signs of liver dysfunction are present.
Ritonavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Rotavirus Vaccine: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Saquinavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Smallpox and Monkeypox Vaccine, Live, Nonreplicating: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Smallpox Vaccine, Vaccinia Vaccine: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Stavudine, d4T: (Major) Patients receiving stavudine with interferons (with or without ribavirin) should be closely monitored for treatment-associated toxicities, especially hepatic decompensation. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation compared to patients not receiving HAART. Additionally, stavudine has been associated with fatal and nonfatal lactic acidosis and hepatomegaly with or without steatosis and should be used cautiously in patients with hepatic disease. Discontinuation of stavudine should be considered as medically appropriate. Dose reduction or discontinuation of interferon, ribavirin, or both should also be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh score greater than 6).
Tbo-Filgrastim: (Major) Filgrastim induces the proliferation of neutrophil-progenitor cells, and, because antineoplastic agents exert toxic effects against rapidly growing cells, filgrastim is contraindicated for use during the 24 hours before or after cytotoxic chemotherapy.
Tenecteplase: (Moderate) An increased risk of bleeding may occur when thrombolytic agents are used following agents that cause clinically significant thrombocytopenia including antineoplastic agents.
Theophylline, Aminophylline: (Major) Alpha interferons, when administered systemically, may decrease the clearance of aminophylline resulting in increased plasma concentrations. Concomitant use may result in a significant increase in theophylline concentrations due to reduced aminophylline clearance. In studies, increases in theophylline levels of 25% up to 100% have occurred. Reductions in CYP1A2 activity have been noted with various alpha interferons, and likely provide a mechanism for the interaction. Monitor theophylline concentrations and for signs and symptoms of toxicity when interferons are used concomitantly; consider appropriate dose adjustments as clinically indicated. (Major) Alpha interferons, when administered systemically, may decrease the clearance of theophylline resulting in increased plasma concentrations. Concomitant use may result in a significant increase in theophylline concentrations due to reduced theophylline clearance. In studies, increases in theophylline levels of 25% up to 100% have occurred. Reductions in CYP1A2 activity have been noted with various alpha interferons, and likely provide a mechanism for the interaction. Monitor theophylline concentrations and for signs and symptoms of theophylline toxicity when interferons are used concomitantly; consider appropriate dose adjustments as clinically indicated.
Thrombolytic Agents: (Moderate) An increased risk of bleeding may occur when thrombolytic agents are used following agents that cause clinically significant thrombocytopenia including antineoplastic agents.
Tipranavir: (Moderate) The concomitant use of interferons and anti-retroviral protease inhibitors should be done with caution as both can cause hepatotoxicity. Closely monitor patients for treatment-associated toxicities, especially hepatic decompensation. Most protease inhibitors have been associated with episodes of liver toxicity. Cirrhotic chronic HCV infected patients co-infected with HIV receiving HAART and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. The HCV-HIV International Panel recommends the management of hepatotoxicity should be based on the knowledge of the mechanisms involved for each drug. Furthermore, they state that there are lower rates of liver-related mortality in coinfected patients taking HAART, even in those with end-stage liver disease, compared with patients not receiving HAART.
Tositumomab: (Moderate) Use of alpha interferons are associated with myelosuppression; additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Tretinoin, ATRA: (Moderate) Use of alpha interferons are associated with myelosuppression; additive myelosuppressive effects may be seen when alpha interferons are given concurrently with other myelosuppressive agents, such as antineoplastic agents or immunosuppressives.
Tuberculin Purified Protein Derivative, PPD: (Moderate) Immunosuppressives may decrease the immunological response to tuberculin purified protein derivative, PPD. This suppressed reactivity can persist for up to 6 weeks after treatment discontinuation. Consider deferring the skin test until completion of the immunosuppressive therapy.
Typhoid Vaccine: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Varicella-Zoster Virus Vaccine, Live: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Vigabatrin: (Major) Vigabatrin is associated with vision loss. The drug should not be used with interferons, which are associated with a potential for serious ophthalmic effects (e.g., retinopathy, optic neuritis, visual impairment), unless the benefit of treatment clearly outweighs the risks.
Yellow Fever Vaccine, Live: (Contraindicated) Live virus vaccines should generally not be administered to an immunosuppressed patient, including those receiving Interferon therapy. Live virus vaccines may induce the illness they are intended to prevent and are generally contraindicated for use during immunosuppressive treatment. The immune response of the immunocompromised patient to vaccines may be decreased, even despite alternate vaccination schedules or more frequent booster doses. If immunization is necessary, choose an alternative to live vaccination, or, consider a delay or change in the immunization schedule. Practitioners should refer to the most recent CDC guidelines regarding vaccination of patients who are receiving drugs that adversely affect the immune system.
Zidovudine, ZDV: (Major) Use interferons and zidovudine together with caution. Closely monitor patients for treatment-associated toxicities, especially hematologic effects and hepatic decompensation, and manage as recommended for the individual therapies. Coadministration of alpha interferons may increase the hematologic toxicity of zidovudine. Interferons and anti-retroviral nucleoside reverse transcriptase inhibitors (NRTIs) are also associated with hepatotoxicity. Patients with chronic, cirrhotic HCV co-infected with HIV receiving NRTIs and alpha interferons appear to be at increased risk for hepatic decompensation (e.g., Childs-Pugh score 6 or more) compared to patients not receiving HAART. Interferon therapy may also reduce zidovudine clearance.

How Supplied

Intron A Intralesional Inj Pwd F/Sol: 10000000IU
Intron A Intralesional Inj Sol: 0.5mL, 5000000IU
Intron A Intramuscular Inj Pwd F/Sol: 10000000IU, 18000000IU, 50000000IU
Intron A Intramuscular Inj Sol: 0.5mL, 3000000IU, 5000000IU
Intron A Intravenous Inj Pwd F/Sol: 10000000IU, 18000000IU, 50000000IU
Intron A Subcutaneous Inj Pwd F/Sol: 10000000IU, 18000000IU, 50000000IU
Intron A Subcutaneous Inj Sol: 0.5mL, 3000000IU, 5000000IU

Maximum Dosage
Adults

20 million International Units/m2/day IV; 35 million International Units/m2 subcutaneous/IM as a single dose.

Geriatric

20 million International Units/m2/day IV; 35 million International Units/m2 subcutaneous/IM as a single dose.

Adolescents

10 million International Units/day subcutaneously.

Children

10 million International Units/day subcutaneously.

Mechanism Of Action

Interferon alfa-2b acts similarly to native interferon alpha. Endogenous alpha-interferons (IFNs) are secreted by leukocytes (e.g., macrophages, B lymphocytes, and non-B non-T lymphocytes) in response to viral infection or various synthetic and biological inducers. All alpha-IFNs share common biologic activities generated by the binding of interferon to the cell-surface receptor. Although the exact mechanism of action is not fully understood, interferon binding to the cell surface receptor is followed by activation of tyrosine kinases, which leads to the production of several IFN-stimulated enzymes such as 2'-5'-oligoadenylate synthetase (2'-5'-OAS) and beta2-microglobulin. These and possibly other IFN-stimulated enzymes are thought to be responsible for the pleiotropic biologic effects of alpha-IFNs, which include antiviral, antiproliferative and immunomodulatory effects, cellular differentiation, regulation of cell surface major histocompatibility antigen expression (HLA class I), and cytokine induction.
 
•Antiviral effects: Interferon exerts antiviral effects by augmenting the production and/or release of specific enzymes. Interferon-induced intracellular enzymes such as 2'5'-OAS and protein kinase contribute to inhibition of viral replication by activating endoribonucleases that cleave single-stranded viral RNA. Thus, translation of viral proteins is inhibited. The activity of IFN-induced enzymes depends on the presence of double-stranded RNA (dsRNA) formed during viral replication. It has been suggested that the antiviral activity of IFNs may be related, in part, to an effect on dsRNA. Interferon-induced enzymes may also inhibit viral penetration and uncoating, and/or viral assembly and release. Expression of major histocompatibility antigens by IFNs may also contribute to antiviral activity by enhancing the lytic effects of cytotoxic T lymphocytes.
 
A wide range of viruses, particularly RNA viruses, are sensitive to the antiviral actions of IFN. Alpha interferons are generally active against the following viruses in vitro: adenovirus; coronavirus; encephalomyocarditis virus; hepatitis B virus; hepatitis C virus (HCV); hepatitis D virus; herpes simplex virus type 1; herpes simplex virus type 2; human immunodeficiency virus (HIV); papillomavirus; poliovirus; rhinovirus; vaccinia virus; varicella-zoster virus; vesicular stomatitis virus; human T-lymphotropic virus type I (HTLV-I). In chronic hepatitis C, INF treatment is associated with normalization of ALT and serum HCV RNA, as well as improvement in liver histopathology, in responding patients. The HCV genotype 1 is more resistant to interferon alfa treatment than other viral genotypes; 75% of persons in US infected with HCV carry this genotype. Many patients with a biochemical and virologic relapse 1—2 months after stopping IFN therapy.
 
•Antineoplastic effects: The antineoplastic activity of interferons may result from a direct antiproliferative effect on the tumor cell and/or the ability of IFN to induce a host response to the tumor (e.g., immunomodulatory effects). Alpha IFNs exert a cytostatic effect on tumor cells, slowing the rate of cell proliferation until cell survival is threatened. The mechanism(s) of antiproliferative activity has not been fully elucidated; several effects may be involved, including the ability of interferons to enhance or inhibit the synthesis of specific proteins, modify cell surface antigen expression, and/or modulate the immune system. Interferon has been shown to prolong all phases of the cell cycle and induce cellular differentiation by promoting cells to enter the nonproliferative G0 (resting) phase. This differentiation effect is thought to be a key mechanism in the treatment of hairy cell leukemia. Inhibition of tumor cell proliferation may also be related to decreased transcription and expression of several oncogenes. Immunomodulatory effects that may contribute to the antitumor activity of interferons include activation of cytotoxic T cells and/or activation of natural killer (NK) cells. Natural killer cells are lymphocytes that recognize cell surface antigens and lyse certain types of tumor cells. The cytotoxic activity of NK cells against tumor cells can be increased following exposure to interferon, although this effect is highly variable. Interferons may increase the proportion of NK cells that become cytotoxic and/or decrease the time needed for NK cells to reach their maximum cytotoxic effect. In addition, interferons activate macrophages and monocytes, resulting in increased phagocytic activity and enhanced cytotoxicity against tumor cells and other target cells. Alpha interferons have been shown to stimulate production of cytokines such as interleukin (IL)-1beta and IL-1ra (an IL-1 receptor antagonist); thus, alpha-IFNs may affect the inflammatory response.
 
•Effect on hepatic microsomal enzymes: Alpha interferons may inhibit microsomal enzymes involved in the hepatic cytochrome P-450 system. The effect of interferon on the CYP450 system may be related to increased enzyme degradation, suppressed enzyme synthesis, or inhibition of cytochrome P-450. Implications of this effect have not been fully evaluated, but the metabolism of certain drugs may be affected.

Pharmacokinetics

Interferon alfa-2b is administered parenterally via intravenous, intramuscular, or subcutaneous routes. The pharmacokinetics of interferon alfa-2b were studied in 12 healthy male volunteers. Mean serum concentrations following intramuscular or subcutaneous administration are similar. The main site for alfa interferon catabolism is the kidney. There is no pharmacokinetic information regarding intralesional administration.

Intravenous Route

Following a single intravenous infusion of 5 million International Units of interferon alfa-2b, the half-life of interferon alfa-2b is about 2 hours with serum levels becoming undetectable in about 4 hours.

Intramuscular Route

The Cmax following 5 million International Units given IM is 18—116 International Units/mL and occurred 3—12 hours after administration of interferon alfa-2b. The elimination half-life following IM injections is 2—3 hours.

Subcutaneous Route

The Cmax following 5 million International Units given subcutaneously is 18—116 International Units/mL and occurred 3—12 hours after administration of interferon alfa-2b. The elimination half-life following subcutaneous injections is 2—3 hours.

Pregnancy And Lactation
Pregnancy

Use interferon alfa-2b during pregnancy only if the potential benefit justifies the potential risk to the fetus. There are no adequate and well controlled studies of interferon alfa-2b in pregnant women. Interferon alfa-2b has shown abortifacient effects in rhesus monkeys. Interferon alfa-2b may be used with ribavirin, and ribavirin is contraindicated in women who are pregnant and in the male partners of women who are pregnant. Significant teratogenic and/or embryocidal effects have been demonstrated in animals exposed to ribavirin.

It is not known if interferon alfa-2b is excreted in breast milk. Because of the potential for serious adverse reactions from interferon alfa-2b in a nursing infant, FDA-approved product labeling recommends discontinuing breast-feeding or interferon alfa-2b therapy, taking into consideration the importance of the drug to the mother. However, previous American Academy of Pediatrics (AAP) recommendations considered interferon alfa to be compatible with breast-feeding. In a case report of 2 pregnant women receiving interferon alfa treatment, interferon concentrations in the breast milk (1.4 units/mL and 6 units/mL) were found to be considerably lower than the maternal serum concentrations (20.8 units/mL and 58 units/mL, respectively) immediately postpartum.