Prescription medicine
Peginterferon alfa 2a Brand names: Pegasys
Peginterferon alfa 2a (Pegasys) is a prescription medicine with an FDA approval on record since 2002. No generic is listed in FDA's NDC Directory.
- No generic listed
- Boxed warning
Check it at the source: the peginterferon alfa 2a FDA label on DailyMed (effective September 2, 2026); the BLA 103964 record on Drugs@FDA; every peginterferon alfa 2a label on DailyMed.
Highlights of the record
FDA label of September 2, 2026; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026
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 Therapy should be withdrawn in patients with persistently severe or worsening signs or symptoms of these conditions.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) ].
Used for
From the label: indications and usagePEGASYS is an inducer of the innate immune response indicated for the treatment of Chronic Hepatitis C (CHC) ( 1.1 ) Adult Patients: In combination therapy with other hepatitis C virus drugs for adults with compensated liver disease.
Forms and strengths
- 0.5ml
Injection (solution).
On the market
- Earliest approval on file
- October 16, 2002 Pegasys, Pharmaand Gmbh; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- No generic approved
- Labelers listed (NDC)
- 1 of which 0 under generic applications, 1 under brand applications, repackagers included
Supply and safety
- Pharmacy cost (NADAC)
- Not in the survey
- Shortage (FDA)
- None current 2 past records
- Recalls by its makers (FDA)
- No recall recorded
- FAERS reports
- 53,742 through July 30, 2026
What is peginterferon alfa 2a used for?
From the label: indications and usagePEGASYS is an inducer of the innate immune response indicated for the treatment of Chronic Hepatitis C (CHC) ( 1.1 ) Adult Patients: In combination therapy with other hepatitis C virus drugs for adults with compensated liver disease. PEGASYS monotherapy is indicated only if patient has contraindication or significant intolerance to other HCV drugs. […]
Conditions named in the indications of peginterferon alfa 2a's FDA labels, with every medicine labeled for each:
From other peginterferon alfa 2a labelsHepatitis B: Treatment of adults with HBeAg-positive and HBeAg-negative chronic hepatitis B (CHB) infection who have compensated liver disease and evidence of viral replication and liver inflammation Pediatric Patients:
FDA pharmacologic class: Interferon alpha.
Source: FDA drug label (Pegasys), pharmaand GmbH, effective September 2, 2026 (SPL set d9290e5b-6d40-2318-e053-2995a90a9916), via openFDA; the full label on DailyMed
What does the patient leaflet for peginterferon alfa 2a say first?
The FDA-approved Medication Guide or Patient Information that comes with the medicine, in its own words.
From the patient leaflet: What is the most important information I should know about PEGASYS?Ribavirin in combination with PEGASYS may cause birth defects or death of your unborn baby.If you are pregnant or your sexual partner is pregnant or plans to become pregnant, do not take PEGASYS and ribavirin combination therapy. You or your sexual partner should not become pregnant during treatment with PEGASYS and ribavirin combination therapy and for 6 months after treatment is over. You must use 2 effective forms of birth control, one of which should be a condom with spermicide during treatment with PEGASYS and ribavirin combination therapy, and for the 6 months after the last dose. Females must have a pregnancy test before starting PEGASYS and ribavirin combination therapy, every month while being treated, and every month for the 6 months after stopping treatment with PEGASYS and ribavirin combination therapy. If you or your female sexual partner becomes pregnant during treatment with PEGASYS and ribavirin or within 6 months after you stop taking PEGASYS and ribavirin,tell your healthcare provider right away. You or your healthcare provider should contact the ribavirin Pregnancy Registry by calling 1-800-593-2214. The ribavirin Pregnancy Registry collects information about the health of you and your baby if you take PEGASYS and ribavirin during pregnancy or if you become pregnant within 6 months after you stop taking PEGASYS and ribavirin. Mental health problems and suicide. […]
From the patient leaflet: What should I avoid while taking PEGASYS?Avoid drinking alcohol. This may make your liver disease worse. Avoid driving or operating machinery if you become dizzy, confused, very sleepy, or tired during treatment with PEGASYS.
From the patient leaflet: How should I store PEGASYS?Store PEGASYS single-dose vials and single-dose prefilled syringes in a refrigerator at 36°F to 46°F (2°C to 8°C). Do notleave PEGASYS out of the refrigerator for more than 24 hours. Do notfreeze or shake PEGASYS. Protect PEGASYS from light. Keep PEGASYS and all medicines out of the reach of children.
Source: FDA drug label (Pegasys), pharmaand GmbH, effective September 2, 2026 (SPL set d9290e5b-6d40-2318-e053-2995a90a9916), via openFDA; the full label on DailyMed
Is there a generic for peginterferon alfa 2a (Pegasys)?
No generic peginterferon alfa 2a is approved (Drugs@FDA, October 8, 2026).
- 2002 earliest approval on file
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
Is peginterferon alfa 2a in shortage?
No peginterferon alfa 2a presentation is listed as in shortage in the FDA Drug Shortage Database (read October 8, 2026); its 2 records are all resolved, the latest updated August 27, 2026. ASHP keeps a separate shortage list, which can differ.
| Presentation | Company | Status | Updated |
|---|---|---|---|
| Pegasys, Injection, 180 ug/.5 mL (NDC 82154-0451-4) | pharmaand GmbH (pharma&) | Resolved | August 27, 2026 |
| Pegasys, Injection, 180 ug/1 mL (NDC 82154-0449-1) | pharmaand GmbH (pharma&) | Resolved | August 27, 2026 |
Every peginterferon alfa 2a presentation in the FDA shortage database
Source: FDA Drug Shortage Database via openFDA, updated October 8, 2026
What does the peginterferon alfa 2a label say about other medicines?
The peginterferon alfa 2a label names 7 other medicines in its interaction, contraindication or warning sections. The labels of 2 other medicines name peginterferon alfa 2a. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
| Medicine named | Section | What the label says |
|---|---|---|
| Abacavir | warnings and precautions | All 14 subjects were on NRTIs, including stavudine, didanosine, abacavir, zidovudine, and lamivudine. |
| Azathioprine | warnings and precautions | Pancytopenia (marked decreases in RBCs, neutrophils and platelets) and bone marrow suppression have been reported in the literature to occur within 3 to 7 weeks after the concomitant administration of pegylated interferon/ribavirin and azathioprine. |
| Lamivudine | warnings and precautions | All 14 subjects were on NRTIs, including stavudine, didanosine, abacavir, zidovudine, and lamivudine. |
| Methadone | drug interactions | DRUG INTERACTIONS Drugs metabolized by CYP1A2: monitor for increased serum levels of theophylline and adjust dose accordingly ( 7.2 ) Methadone: monitor for signs and symptoms of methadone toxicity ( 7.3 ) Nucleoside analogues: closely monitor for toxicities. |
| Ribavirin | contraindications | 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) ]. |
| Theophylline | drug interactions | DRUG INTERACTIONS Drugs metabolized by CYP1A2: monitor for increased serum levels of theophylline and adjust dose accordingly ( 7.2 ) Methadone: monitor for signs and symptoms of methadone toxicity ( 7.3 ) Nucleoside analogues: closely monitor for toxicities. |
| Zidovudine | drug interactions | Reduce or discontinue the dose of PEGASYS or ribavirin or both should the events worsen ( 7.4 ) Zidovudine: monitor for worsening neutropenia and/or anemia with PEGASYS and/or ribavirin |
Source: FDA drug label (Pegasys), pharmaand GmbH, effective September 2, 2026 (SPL set d9290e5b-6d40-2318-e053-2995a90a9916), via openFDA; the full label on DailyMed
What do FAERS reports show for peginterferon alfa 2a?
The FDA Adverse Event Reporting System holds 53,742 reports that list peginterferon alfa 2a among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 1,798 are coded as a death and 9,496 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What next?
- Peginterferon alfa 2a side effects
- the label's list beside FAERS reports
- Peginterferon alfa 2a shortage record
- every presentation, company and date
- Check an interaction
- what two or more labels say about each other