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Peginterferon Alfa-2a

Pegasys · ATC code L03AB11

Also known as: Peginterferon α

Key facts
Active substance
Peginterferon Alfa-2a
Drug class
Interferon
ATC code
L03AB11
Authorisation
centrally authorised across the EU (EMA)
Dosage forms
Pegasys 90 micrograms solution for injection in pre-filled syringe / Pegasys 135 micrograms solution for injection in pre-filled syringe / Pegasys 180 micrograms solution for injection in pre-filled syringe · Pegasys 180 micrograms solution for injection
Marketing authorisation holder
pharmaand GmbH
Information as of
2026-10-29

Key facts

Peginterferon alfa-2a (Pegasys) is a pegylated interferon given by subcutaneous injection. It is used for chronic hepatitis B and C, polycythaemia vera and essential thrombocythaemia.

What it is used for

  • Pre-filled syringes 90/135/180 micrograms: monotherapy in adults with polycythaemia vera or essential thrombocythaemia.
  • Chronic hepatitis B: adults with compensated liver disease (HBeAg-positive or -negative), and HBeAg-positive non-cirrhotic children 3 years of age and older.
  • Chronic hepatitis C: adults with compensated liver disease, in combination with other medicines; children 5 years and older see the full text.

Dosing

  • Polycythaemia vera and essential thrombocythaemia: start at 45 micrograms once weekly subcutaneously, increasing by 45 micrograms monthly until blood counts stabilise; maximum single dose 180 micrograms weekly.
  • Chronic hepatitis B (adults): 180 micrograms once weekly for 48 weeks.
  • Chronic hepatitis C (adults): 180 micrograms once weekly with ribavirin or as monotherapy; duration depends on genotype and response (e.g. 24 or 48 weeks), see the full text.
  • Severe renal impairment or end stage renal disease: 135 mcg once weekly; dose reductions for neutropenia or thrombocytopenia.

Contraindications

  • Hypersensitivity to the active substance, alfa interferons or any of the excipients.
  • Autoimmune disease or autoimmune hepatitis; thyroid disease not controlled by conventional treatment.
  • Severe hepatic dysfunction or decompensated cirrhosis; severe pre-existing cardiac disease.
  • Combination with telbivudine; neonates and young children up to 3 years (benzyl alcohol); severe psychiatric conditions in children.

Important warnings

  • Severe CNS effects, particularly depression, suicidal ideation and attempted suicide, also after stopping treatment.
  • Thyroid function abnormalities; evaluate TSH and T4 before starting.
  • Eye disorders (e.g. retinal haemorrhage); discontinue for new or worsening ophthalmologic disorders.
  • Pulmonary symptoms including pneumonia and pneumonitis.
  • Blood count changes (neutropenia, thrombocytopenia) require dose adjustment.

Side effects

  • In polycythaemia vera and essential thrombocythaemia, most frequent: flu-like symptoms, injection site reactions, peripheral sensory neuropathies, visual disturbances, depression, leukopenia, hypertension, fatigue, anaemia, diarrhoea, nausea, headache.
  • Very common in hepatitis: anorexia, depression, insomnia, headache, dizziness.
  • Serious and less frequent: suicide, sepsis, aplastic anaemia, vision loss.

Interactions

  • Pegasys inhibits CYP1A2 and increased theophylline AUC by 25%; monitor theophylline levels.
  • Combination with telbivudine is contraindicated (risk of peripheral neuropathy).

Pregnancy and breastfeeding

  • Use in pregnancy only if the benefit justifies the risk to the foetus; with ribavirin, also refer to the ribavirin product information.
  • Breastfeeding should be discontinued before starting treatment.

Summary of the official product information, written with AI on 2026-10-29. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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For patients

Package leaflet, verbatim

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

EU – centrally authorised (all member states)

  • Pegasyspharmaand GmbH · EMEA/H/C/000395

Source: European Medicines Agency (EMA), product information

Turkey

  • PegasysABDİ İBRAHİM İLAÇ SAN. VE TİC. A.Ş. · 4 register entries

Source: TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, as of 2026-10-16

Brand names in 3 more European countries
Iceland
Pegasys
Liechtenstein
Pegasys
Norway
Pegasys

EMA – Article 57 product data (EU/EEA), 2026-10-29

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

Other substances in the same group

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Sources

  1. European Medicines Agency. Pegasys – EPAR, Product Information. 2026-10-29. https://www.ema.europa.eu/en/documents/product-information/pegasys-epar-product-information_en.pdf
  2. TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, 2026-10-16. https://www.titck.gov.tr/dinamikmodul/85
  3. Wikidata (CC0): ATC L03AB.

Editorial: Medelix editorial team · last updated 2026-10-29 · How these pages are made · Report an error

Source: European Medicines Agency (EMA), product information. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.