What is the maintenance dose of acyclovir for genital herpes?

Maintenance Dose of Acyclovir for Genital Herpes

For chronic suppressive therapy of recurrent genital herpes, acyclovir 400 mg orally twice daily is the standard maintenance dose, continued for up to 12 months followed by re-evaluation. 1, 2

Standard Suppressive Dosing

• The FDA-approved maintenance regimen is acyclovir 400 mg orally twice daily for up to 12 months. 2
• The CDC guidelines confirm this as the preferred preventative dose for HSV suppression. 1
• After 1 year of continuous suppressive therapy, treatment should be discontinued to reassess the patient's recurrence rate, as the frequency and severity of genital herpes may change over time. 1, 2

Alternative Dosing Options

• Alternative FDA-approved regimens include acyclovir 200 mg orally 3-5 times daily, though the twice-daily dosing offers superior convenience and adherence. 2
• For patients with very frequent recurrences (≥10 episodes per year), the standard 400 mg twice daily remains effective, though some patients may benefit from higher frequency dosing. 1, 3
• Patients with fewer recurrences (<10 per year) are effectively managed with the standard 400 mg twice daily regimen. 3

Clinical Efficacy

• Suppressive therapy with acyclovir 400 mg twice daily reduces HSV recurrence frequency by at least 75% in patients with frequent recurrences (≥6 episodes per year). 1
• In clinical trials, 44% of patients receiving 400 mg twice daily remained completely recurrence-free for one year, compared to only 2% receiving placebo. 4
• The mean number of recurrences per year decreased from 11.4 with placebo to 1.8 with suppressive acyclovir therapy. 4

Special Populations

• For HIV-infected or immunocompromised patients, higher doses of acyclovir (400 mg orally 3-5 times daily) are often beneficial. 1, 5
• In adults and adolescents with genital herpes, the standard 400 mg twice daily dosing applies. 6
• In children <45 kg, acyclovir 20 mg/kg body weight (max 400 mg/dose) orally 3 times daily is recommended for acute treatment, though suppressive therapy dosing in children is less well-established. 6

Renal Dose Adjustment

• Dose adjustment is mandatory in renal impairment, as acyclovir is primarily renally excreted. 7, 2
• For creatinine clearance 10-25 mL/min/1.73 m², reduce to 400 mg every 12 hours. 2
• For creatinine clearance 0-10 mL/min/1.73 m², reduce to 200 mg every 12 hours. 2
• For hemodialysis patients, administer an additional dose after each dialysis session. 2

Critical Patient Counseling Points

• Patients must understand that acyclovir does not eradicate latent virus or prevent future recurrences after discontinuation. 7
• Suppressive acyclovir reduces but does not eliminate asymptomatic viral shedding, and transmission can occur during asymptomatic periods despite therapy. 1, 7
• The extent to which suppressive therapy prevents HSV transmission to partners remains incompletely defined. 1

Common Pitfalls to Avoid

• Do not continue suppressive therapy indefinitely without re-evaluation after 12 months, as the natural history of recurrences may improve over time. 1, 2
• Avoid assuming complete protection against transmission; counsel patients that viral shedding and transmission risk persist despite suppressive therapy. 1, 7
• Monitor for acyclovir-resistant strains in immunocompromised patients, particularly if lesions persist despite therapy. 7
• Do not use high-dose valacyclovir (8 g/day) in immunocompromised patients due to association with hemolytic uremic syndrome or thrombotic thrombocytopenic purpura. 1

Safety Profile

• Long-term suppressive acyclovir therapy for up to two years has demonstrated excellent safety and tolerability with no evidence of cumulative toxicity. 8
• No clinically significant changes in hematologic or blood chemistry parameters were detected during prolonged therapy. 8
• Viral resistance to acyclovir during suppressive therapy has not been a significant problem in immunocompetent patients. 4, 5