What is the recommended dose of famciclovir (famciclovir) for an adult patient with herpes simplex virus (HSV) infection?

Famciclovir Single-Dose Regimen for HSV

For herpes labialis (cold sores), the one-time dose of famciclovir is 1500 mg as a single dose, initiated at the first sign or symptom of infection. 1

Indication-Specific Dosing

Herpes Labialis (Cold Sores)

• The FDA-approved single-dose regimen is famciclovir 1500 mg taken once at the first sign of symptoms (tingling, itching, burning, pain, or lesion). 1
• This single-day, high-dose regimen has been demonstrated to be effective for episodic treatment and improves patient compliance by eliminating the need for multiple daily doses. 2
• Treatment must be initiated at the earliest prodromal symptoms for maximum efficacy. 1

Recurrent Genital Herpes (Immunocompetent Patients)

• For recurrent genital herpes episodes, the FDA-approved single-day regimen is famciclovir 1000 mg twice daily for 1 day (total of 2 doses). 1
• Therapy should be initiated at the first sign or symptom of a recurrent episode (tingling, itching, burning, pain, or lesion). 1
• The efficacy of famciclovir when initiated more than 6 hours after onset of symptoms or lesions has not been established. 1
• This high-dose, single-day approach allows treatment within the narrow therapeutic window early in HSV infection episodes. 2

Alternative Multi-Day Regimens

When Single-Dose is Not Appropriate

• For HIV-infected patients with recurrent orolabial or genital herpes, the recommended dose is famciclovir 500 mg twice daily for 7 days (not a single-dose regimen). 1
• For chronic suppressive therapy of recurrent genital herpes in immunocompetent patients, famciclovir 250 mg twice daily is used continuously (not episodic single-dose treatment). 1

Critical Timing Considerations

• Patient-initiated episodic therapy (PIE) with these single-day regimens allows antiviral administration in the narrow therapeutic window that occurs early in HSV infection, potentially halting lesion development. 2
• The efficacy of famciclovir when initiated more than 48 hours after symptom onset in HIV-infected patients has not been established. 1

Important Limitations

• The efficacy and safety of famciclovir have not been established for first episode of genital herpes, ophthalmic zoster, or immunocompromised patients (except HIV-infected patients with recurrent orolabial or genital herpes). 1
• Single-dose regimens are specifically for episodic treatment of recurrences, not for suppressive therapy or initial episodes. 1