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pegylated interferon alfa

Drug monograph

CDSCO approved
EXCRETION
not curated
INTERACTIONS
none in our sources
PREGNANCY
not curated

Mechanism

Not yet extracted

Indications

viral hepatitisChronic Hepatitis B virus (HBV) infection (preferred agent)Chronic Hepatitis C virus (HCV) infection (pegIFN-α2a, for children 5 years or older, previously used for adults but replaced by DAAs)Hepatitis D virus (limited success)

Dosing

Adult
180 μg subcutaneously once weekly for 48–52 weeks (pegIFN-α2a)
Pediatric
6 million IU/m2 thrice weekly (interferon-α2b) for children 1 year or older; 180 μg/1.73 m2 × body surface area once weekly (pegIFN-α2a) for children 5 years or older with HCV
Renal adjustment
Reduced for ClCr less than 30 mL/min; dose reductions required for end-stage renal disease (ESRD) for both pegIFN products

Pharmacokinetics

Onset
Antiviral state in peripheral blood mononuclear cells peaks at 24 h and decreases slowly to baseline by 6 days after injection.
Half-life
30–54 h (pegIFN-α2b); 80–90 h (pegIFN-α2a)
Excretion
About 30% of pegIFN-α2b is cleared by the kidneys; the remainder by liver and cellular degradation of IFN-receptor complexes. PegIFN-α2a is cleared by the liver and kidney.

Contraindications

  • Advanced liver disease
  • Decompensated cirrhosis
  • Pregnancy

Side effects

Common
FeverChillsHeadacheMyalgiaArthralgiaNauseaVomitingDiarrheaFatigue/astheniaPyrexiaInjection site inflammationNeutropenia
Serious
  • Depression
  • Myelosuppression (granulocytopenia, thrombocytopenia)
  • Neurotoxicity (somnolence, confusion, behavioral disturbance, seizures)
  • Debilitating neurasthenia
  • Autoimmune disorders (thyroiditis, hypothyroidism)
  • Cardiovascular effects (hypotension, tachycardia)
  • Elevations in hepatic enzymes
  • Elevations in triglycerides
  • Alopecia
  • Proteinuria
  • Azotemia
  • Interstitial nephritis
  • Autoantibody formation
  • Pneumonia
  • Hepatotoxicity
  • Fatal neuropsychiatric disorders
  • Fatal autoimmune disorders
  • Fatal ischemic disorders
  • Fatal infectious disorders

Drug interactions

Other Cardiotoxic Drugs
Moderate
Textbook

Increased cardiotoxic effects.

Monitor for cardiac effects.

Source: G&G 14e · p1231

Other Neurotoxic Drugs
Moderate
Textbook

Increased neurotoxicity.

Monitor for signs of neurotoxicity.

Source: G&G 14e · p1231

Ribavirin
Moderate
Textbook

Increased hematological toxicity.

Monitor hematological parameters.

Source: G&G 14e · p1231

Zidovudine
Moderate
Textbook

Increased hematological toxicity.

Monitor hematological parameters.

Source: G&G 14e · p1231

Related guidelines

Other Unclassified drugs

Ask House about pegylated interferon alfa

Continue into a citation-backed clinical answer with the drug context already attached.

Sources: Goodman & Gilman 14e·Verified: 2026-05-10 · House clinical team