What is the recommended dose of acyclovir (antiviral medication) for an adult patient with a history of genital herpes for suppressive therapy?

Acyclovir Suppressive Therapy for Genital Herpes

For suppressive therapy of recurrent genital herpes in adults, acyclovir 400 mg orally twice daily is the recommended dose. 1, 2, 3

Standard Suppressive Dosing

• The CDC recommends acyclovir 400 mg orally twice daily for continuous suppression in patients with frequent recurrences (≥6 episodes per year). 1, 2
• This regimen reduces recurrence frequency by at least 75%. 1, 2
• The FDA label confirms 400 mg twice daily for chronic suppressive therapy for up to 12 months, followed by re-evaluation. 3

Alternative Dosing Regimens

• Alternative suppressive regimens include 200 mg three times daily to 200 mg five times daily, though these are less convenient and not preferred. 3
• For immunosuppressed patients, higher doses may be required: 400 mg orally 3-5 times daily. 1

Duration and Re-evaluation

• Therapy should be continued for up to 12 months, after which the frequency and severity of genital herpes should be re-evaluated to assess the need for continuation. 3
• Long-term suppression for up to 5 years has been demonstrated to be safe and effective, with 85-90% of patients remaining recurrence-free during any given quarter of the fifth year. 4
• After one year of suppressive therapy, 44% of patients remained completely free of recurrences compared to only 2% receiving episodic treatment. 5

Important Clinical Considerations

Efficacy Expectations

• Mean annual recurrences decrease from approximately 12 episodes per year to 1.7-1.8 episodes during suppressive therapy. 5, 4
• More than 20% of patients receiving continuous suppressive therapy for 5 years remain completely recurrence-free. 4

Post-Treatment Recurrence

• After discontinuation of suppressive therapy, recurrences typically return within 1-4 weeks in approximately 69% of patients. 6
• The frequency of recurrences after stopping therapy returns to pre-treatment levels in most patients. 6

Resistance Monitoring

• No clinically significant acyclovir resistance has been observed even after 6 years of continuous suppressive therapy in immunocompetent patients. 4
• Resistance may emerge in immunocompromised patients; if lesions persist despite therapy, consider foscarnet 40 mg/kg IV three times daily as alternative treatment. 1

Renal Impairment Adjustments

• For creatinine clearance 10-25 mL/min: reduce to 400 mg once daily 3
• For creatinine clearance <10 mL/min: reduce to 200 mg every 12 hours 3
• For hemodialysis patients, administer an additional dose after each dialysis session. 3

Patient Counseling Points

• Acyclovir does not eradicate latent virus or prevent future recurrences after discontinuation. 2
• Viral shedding and transmission can occur during asymptomatic periods despite suppressive therapy. 2
• Patients should abstain from sexual activity when lesions are present. 7