What is the recommended dose of valacyclovir (Valtrex) for an adult patient with herpes genitalis?

Valacyclovir Dosing for Genital Herpes

For genital herpes, valacyclovir dosing depends on whether you are treating an initial episode (1 gram twice daily for 10 days), a recurrent episode (500 mg twice daily for 3 days), or providing suppressive therapy (1 gram once daily, or 500 mg once daily for patients with ≤9 recurrences per year). 1

Initial Episode of Genital Herpes

• Administer valacyclovir 1 gram twice daily for 10 days 1
• Therapy is most effective when initiated within 48 hours of symptom onset 1
• This regimen is as effective as acyclovir 200 mg five times daily for 10 days, with the advantage of simpler dosing 2, 3

Recurrent Episodes of Genital Herpes

• Administer valacyclovir 500 mg twice daily for 3 days 1
• Initiate treatment at the first sign or symptom of an episode (prodrome, tingling, lesion appearance) 1
• Treatment should ideally begin within 48 hours of symptom onset for maximum benefit 4
• The 500 mg twice daily regimen is as effective as 1 gram twice daily or acyclovir 200 mg five times daily 2, 3, 5

Suppressive Therapy for Recurrent Genital Herpes

Standard Suppressive Dosing (Immunocompetent Patients)

• For patients with ≥10 recurrences per year: valacyclovir 1 gram once daily 1
• For patients with ≤9 recurrences per year: valacyclovir 500 mg once daily 1
• The 500 mg once daily dose is less effective in patients with very frequent recurrences (≥10 episodes per year), who require the higher 1 gram daily dose 4, 6
• Daily suppressive therapy reduces recurrences by ≥75% among patients with frequent episodes 4
• Safety and efficacy have been documented for up to 1 year with valacyclovir 4

Suppressive Dosing for HIV-Infected Patients

• For HIV-infected patients with CD4+ count ≥100 cells/mm³: valacyclovir 500 mg twice daily 4, 1
• This higher dosing (compared to immunocompetent patients) accounts for potentially more severe and frequent recurrences in this population 4

Transmission Reduction

• For reduction of transmission to uninfected partners: valacyclovir 500 mg once daily 1
• This indication applies to patients with a history of ≤9 recurrences per year 1

Important Clinical Considerations

Renal Dosing Adjustments

• For patients with creatinine clearance 30-49 mL/min, no dose reduction is needed for standard genital herpes regimens 4
• However, dose adjustments are required for more severe renal impairment (not specified in the evidence for genital herpes dosing) 5
• No laboratory monitoring is needed for patients on suppressive therapy unless they have substantial renal impairment 4

Treatment Duration and Discontinuation

• After 1 year of continuous suppressive therapy, consider discussing discontinuation to reassess recurrence frequency, as recurrences may decrease over time 4
• Valacyclovir neither eradicates latent virus nor affects subsequent risk, frequency, or severity of recurrences after discontinuation 7

Treatment Failure and Resistance

• If lesions persist despite appropriate valacyclovir treatment, consider HSV resistance 4
• All acyclovir-resistant strains are also resistant to valacyclovir 4
• For acyclovir-resistant HSV, IV foscarnet (40 mg/kg IV every 8 hours until clinical resolution) is the treatment of choice 4

Common Pitfalls to Avoid

• Do not use the 500 mg once daily suppressive dose for patients with ≥10 recurrences per year—this population requires 1 gram once daily for adequate suppression 4, 6
• Do not confuse genital herpes dosing with herpes zoster dosing—herpes zoster requires 1 gram three times daily for 7 days, which is a much higher total daily dose 1
• Valacyclovir can be given without regard to meals 1
• Suppressive therapy reduces but does not eliminate asymptomatic viral shedding, so transmission risk counseling remains important 4