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Peginterferon Alfa-2a

Also known as: Pegasys

Interferon alpha

Route: Subcutaneous

Check Peginterferon Alfa-2a Interactions →

6 interactions on record⛔ Black Box Warning

Peginterferon Alfa-2a has 6 known drug interactions based on U.S. FDA drug labeling data. 2 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Nucleoside Analogues, Zidovudine, Methadone. Patients taking Peginterferon Alfa-2a should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.

Total: 6
Major: 2
Moderate: 2
Minor: 2

Major (2)

Peginterferon Alfa-2a + Nucleoside Analogues— Use with PEGASYS/ribavirin and other HCV antivirals associated with hepatic decompensation (some fatal). Monitor closely…
Peginterferon Alfa-2a + Zidovudine— Concomitant use with PEGASYS and ribavirin increases risk of severe neutropenia and severe anemia. Monitor closely and c…

Moderate (2)

Peginterferon Alfa-2a + Methadone— PEGASYS increases methadone levels by 10-15%. Monitor for signs and symptoms of methadone toxicity.
Peginterferon Alfa-2a + Theophylline— PEGASYS inhibits CYP1A2, increasing theophylline AUC by 25%. Monitor serum levels and adjust dose accordingly.

Minor (2)

Peginterferon Alfa-2a + Eltrombopag— No dose adjustment recommended when coadministered with eltrombopag.
Peginterferon Alfa-2a + Eltrombopag Olamine— No dose adjustment recommended when coadministered with eltrombopag.

Peginterferon Alfa-2a + Nucleoside Analogues⚠️Major

Use with PEGASYS/ribavirin and other HCV antivirals associated with hepatic decompensation (some fatal). Monitor closely for toxicities and consider dose reduction or discontinuation.

Peginterferon Alfa-2a + Zidovudine⚠️Major

Concomitant use with PEGASYS and ribavirin increases risk of severe neutropenia and severe anemia. Monitor closely and consider dose reduction or discontinuation.

Peginterferon Alfa-2a + Methadone🟡Moderate

PEGASYS increases methadone levels by 10-15%. Monitor for signs and symptoms of methadone toxicity.

Peginterferon Alfa-2a + Theophylline🟡Moderate

PEGASYS inhibits CYP1A2, increasing theophylline AUC by 25%. Monitor serum levels and adjust dose accordingly.

Peginterferon Alfa-2a + Eltrombopag🟢Minor

No dose adjustment recommended when coadministered with eltrombopag.

Peginterferon Alfa-2a + Eltrombopag Olamine🟢Minor

No dose adjustment recommended when coadministered with eltrombopag.

⛔ FDA Black Box Warning

WARNING: RISK OF SERIOUS DISORDERS WARNING: RISK OF SERIOUS DISORDERS See full prescribing information for complete boxed warning. Risk of Serious Disorders May cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Monitor closely and withdraw therapy with persistently severe or worsening signs or symptoms of the above disorders ( 5 ) Risk of Serious Disorders Alpha interferons, including PEGASYS (peginterferon alfa-2a), may cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Patients should be monitored closely with periodic clinical and laboratory evaluations. Therapy should be withdrawn in patients with persistently severe or worsening signs or symptoms of these conditions. In many, but not all cases, these disorders resolve after stopping PEGASYS therapy [see Warnings and Precautions (5.2 , 5.5 , 5.8 , 5.11 , 5.14 , 5.16) , Adverse Reactions (6.1) and Nonclinical Toxicology (13.1) ] .

Contraindications

4 CONTRAINDICATIONS PEGASYS is contraindicated in patients with: Known hypersensitivity reactions such as urticaria, angioedema, bronchoconstriction, anaphylaxis, or Stevens-Johnson syndrome to alpha interferons, including PEGASYS, or any of its components. Autoimmune hepatitis Hepatic decompensation (Child-Pugh score greater than 6 [class B and C]) in cirrhotic patients before treatment Hepatic decompensation with Child-Pugh score greater than or equal to 6 in cirrhotic CHC patients coinfected with HIV before treatment PEGASYS is contraindicated in neonates and infants because it contains benzyl alcohol. Benzyl alcohol is associated with an increased incidence of neurologic and other complications which are sometimes fatal in neonates and infants. When PEGASYS is used in combination with other HCV antiviral drugs, the contraindications applicable to those agents are applicable to combination therapies. PEGASYS combination treatment with ribavirin is contraindicated in women who are pregnant and men whose female partners are pregnant [See Warnings and Precautions (5.1) and Use in Specific Populations (8.1) ]. Refer to the prescribing information of the other HCV antiviral drugs, including ribavirin, for a list of their contraindications. Autoimmune hepatitis ( 4 ) Hepatic decompensation in patients with cirrhosis ( 4 ) Use in neonates/infants ( 4 ) Known hypersensitivity reactions such as urticaria, angioedema, bronchoconstriction and anaphylaxis to alpha interferons or any component of the product ( 4 ) Additional contraindications for use with other HCV antiviral drugs: When used in combination with other HCV antiviral drugs, all contraindications also apply to PEGASYS combination therapy ( 4 ) Ribavirin is contraindicated in pregnant women and men whose female partners are pregnant ( 4 , 8.1 )

Pregnancy & Breastfeeding

8.1 Pregnancy Pregnancy Exposure Registry – Use with ribavirin A ribavirin Pregnancy Registry has been established to monitor maternal and fetal outcomes of pregnancies of female patients and female partners of male patients exposed to ribavirin during pregnancy or who become pregnant within 6 months following cessation of treatment with ribavirin. Healthcare providers and patients are encouraged to report such cases by calling 1-800-593-2214. Risk Summary There are no adequate and well-controlled studies of PEGASYS in pregnant women to inform a drug-associated risk. Based on animal reproduction studies, PEGASYS can cause fetal harm and should be assumed to have abortifacient potential. Non-pegylated interferon alfa-2a treatment caused abortion when given to pregnant rhesus monkeys (see Data ). The background risk of major birth defects and miscarriage in the indicated population is 3% and 4-22%, respectively. In the U.S. general population, the estimated background risk for major birth defects and miscarriage in the clinically recognized pregnancies is 2-4% and 15-20%, respectively. PEGASYS combination treatment with ribavirin is contraindicated in women who are pregnant and in the male partners of women who are pregnant [see Contraindications (4) , Warnings and Precautions (5.1) , and ribavirin labeling] . Significant teratogenic and/or embryocidal effects have been demonstrated in all animal species exposed to ribavirin [see ribavirin labeling]. Data Animal Data – Groups of 8 or 9 pregnant rhesus monkeys were given non-pegylated interferon alfa-2a by daily intramuscular injection over days 22 to 70 of gestation at doses of 1, 5 and 25 million IU/day. Two, 3 and 6 monkeys aborted in the low, mid and high dose groups compared with 1 in the control group. Maternal toxicity, characterized by transient body weight loss, was seen at all dose levels. There were too few remaining pregnancies to assess teratogenic potential but no developmental abnormalities were observed

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.