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Famvir (Famcyclovir)

Antiviral

Brand Names

Famvir®

Drug Information

Pharmacology

Selectively inhibits Herpes viral DNA synthesis

Contraindications

General
  • Famciclovir is contraindicated in patients known to be hypersensitive to it or penciclovir.
  • It should be used with caution (and dosage adjustment) in patients with renal dysfunction.

Adverse Effects

General
  • In humans, famciclovir can cause nausea, vomiting, diarrhea, and headache. Neutropenia has been reported and renal failure can occur particularly when doses are not adjusted in patients with renal dysfunction.
Cat
  • Adverse effects in cats are not well documented, but the drug appears to be tolerated quite well when used for up to 3 weeks. At doses of 90 mg/kg by mouth every 8 hours, anorexia and polydipsia have been noted in some cats.

Interactions

General Interactions
  • Food may reduce bioavailability – give on an empty stomach
Drug Interactions
Probenecid
  • Can reduce the amount of penciclovir excreted by the kidneys and increase penciclovir plasma levels.

Comments

Food may reduce bioavailability – give on an empty stomach. Consider occasional CBC’s and creatinine to monitor for neutropenia or renal dysfunction if using the drug chronically.

Available Forms

Human
  • Oral Tablets (film-coated): 125 mg, 250 mg, & 500 mg; Famvir®, generic
Veterinary – General
  • None