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Nucleoside antiviral (penciclovir prodrug)

Famciclovir

Brand names: Famvir

Adult dose

Dose: Herpes zoster: 500mg TDS for 7 days. Recurrent genital herpes: 1g BD for 1 day
Route: PO
Frequency: TDS or BD

Dose adjustments

Renal

CrCl 40–59: standard. 20–39: 500mg BD (zoster). <20: 250mg OD (zoster)

Clinical pearls

  • Higher bioavailability than aciclovir; less frequent dosing
  • Start within 72h of zoster rash for benefit

Contraindications

  • Hypersensitivity to penciclovir/famciclovir

Side effects

  • Headache
  • Nausea
  • Diarrhoea
  • Rash

Interactions

  • Probenecid (raised levels)

Monitoring

  • U&E for prolonged use

Reference: BNF; NICE CKS; https://bnf.nice.org.uk/drugs/famciclovir/. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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