Famciclovir
Administration
- Type: Antiviral
- Dosage Forms:
- Routes of Administration: Oral
- Common Trade Names: Famvir
Adult Dosing
- 150-1000mg PO BID
Herpes zoster oticus
- 500mg TID x 7 days
HSV-1
- 500mg PO TID
Indications by Disease
| Disease | Dose | Context |
|---|---|---|
| Herpes Simplex Virus-2 | 250mg PO q8hrs x 7-10 days | Initial Episode |
| Herpes Simplex Virus-2 | 125mg PO q12hrs for 5 days or 1g PO q12hrs for 1 day or 500mg PO once then 250mg PO q12hrs for 2 days | Recurrence |
| Herpes Simplex Virus-2 | 250mg PO q12hrs daily | Suppressive |
| Herpes gingivostomatitis | 500mg PO BID x 7 days | Normal host |
| Herpes gingivostomatitis | 500mg PO BID x 7 days | Immunocompromised |
| Herpes labialis | 500mg PO BID x 7 days | Normal host |
| Herpes labialis | 500mg PO BID x 7 days | Immunocompromised |
Pediatric Dosing
Safety/efficacy not established
Indications by Disease
Special Populations
- Pregnancy Rating: B
- Lactation risk: Infant risk cannot be ruled out
- Renal dosing: reduced dose
- Hepatic dosing: no adjustment for mild-moderate impairment
- Famvir Pregnancy Registry: 1-888-669-6682
Contraindications
- Allergy to class/drug
Adverse Reactions
Serious
- Neutropenia, thrombocytopenia
- Skin reaction, severe
- Hallucinations, delirium
Common
- Nausea/vomiting, diarrhea
- Headache
- Fatigue
- Elevated AST/ALT
- Pruritus
- Paresthesia
- Flatulence
Pharmacology
- Half-life: 2.3h
- Metabolism: Hepatic, CYP450
- Excretion: Mostly renal
Mechanism of Action
- Inhibits DNA polymerase, selectively inhibiting herpes viral DNA synthesis and replication