Products
Famciclovir is commercially available in the form of film-coated tablets (Famvir). It has been approved in many countries since 1995.
Structure and properties
Famciclovir (C14H19N5O4, Mr = 321.3 g/mol) is the orally available prodrug of penciclovir, which is itself a prodrug of penciclovir triphosphate. Famciclovir exists as a white to yellowish powder that is initially soluble in water but precipitates again as famciclovir monohydrate. It is a synthetic, acyclic guanine derivative.
Effects
Famciclovir (ATC J05AB09) has antiviral properties against herpes viruses. The effects are based on inhibition of viral DNA replication. Famciclovir is first metabolized to penciclovir and, in virus-infected cells, by viral and cellular kinases to penciclovir triphosphate. Penciclovir triphosphate is the actual active ingredient.
Indications
For the treatment of infections with herpes viruses:
Dosage
According to the professional information. The drug should be administered as soon as possible after the onset of the disease. The tablets are usually taken two to three times daily, independent of meals. The duration of therapy depends on the indication.
Contraindications
- Hypersensitivity
For complete precautions, see the drug label.
Interactions
Famciclovir is metabolized by aldehyde oxidase, among other enzymes, and is an inhibitor of this enzyme. Corresponding drug-drug interactions are possible. Another interaction has been described with probenecid.
Adverse effects
Possible adverse effects include headache, nausea, diarrhea, and drowsiness. Very rarely, acute renal failure has been reported in patients with renal disease.
