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Interferon (immunomodulator)

Interferon beta

Brand names: Avonex, Rebif, Betaferon, Plegridy, Extavia

Adult dose

Dose: Brand-specific — e.g. Avonex 30 micrograms IM weekly; Rebif 22–44 micrograms SC 3×/week; Plegridy 125 micrograms SC every 2 weeks
Route: SC/IM
Frequency: varies

Clinical pearls

  • Relapsing-remitting MS — first-line DMT
  • Pre-treatment LFTs, FBC, TFTs

Contraindications

  • Severe depression / suicidality
  • Decompensated hepatic disease
  • Pregnancy (relative)

Side effects

  • Flu-like symptoms (very common — pre-medicate paracetamol)
  • Injection site reactions
  • Hepatotoxicity
  • Cytopenias
  • Depression
  • Thyroid dysfunction
  • Thrombotic microangiopathy (rare)

Interactions

  • Live vaccines
  • Hepatotoxic drugs

Monitoring

  • LFTs
  • FBC
  • TFTs
  • Mental state

Reference: BNF; NICE NG220; ABN MS guidelines; https://bnf.nice.org.uk/drugs/interferon-beta/. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.