Treatment of Herpes Simplex Anus
For herpes proctitis (anorectal herpes simplex), treat with oral acyclovir 400 mg five times daily for 10 days or until clinical resolution, which is a higher dose and longer duration than standard genital herpes treatment. 1
First Clinical Episode of Herpes Proctitis
The CDC specifically recommends acyclovir 400 mg orally 5 times a day for 10 days or until clinical resolution for first-episode herpes proctitis. 1 This differs from standard genital herpes treatment (200 mg five times daily for 7-10 days) because anorectal involvement typically requires more aggressive therapy. 1
Alternative Modern Regimens
While the older CDC guidelines specify acyclovir dosing, newer antiviral options with more convenient dosing include:
- Valacyclovir 1 g orally twice daily for 7-10 days (may be extended if healing incomplete after 10 days) 2
- Famciclovir 250 mg orally three times daily for 7-10 days 2
These agents are bioavailable prodrugs that achieve similar therapeutic levels with less frequent dosing, improving adherence. 3, 4
Recurrent Episodes of Anorectal Herpes
For recurrent episodes, episodic therapy should be initiated during prodrome or within 1 day of lesion onset for maximum effectiveness. 2, 5
Recommended regimens for recurrent episodes:
- Valacyclovir 500 mg orally twice daily for 5 days 5
- Acyclovir 400 mg orally three times daily for 5 days 5
- Acyclovir 800 mg orally twice daily for 5 days 5
- Famciclovir 125 mg orally twice daily for 5 days 5
Suppressive Therapy for Frequent Recurrences
For patients with ≥6 recurrences per year, daily suppressive therapy reduces recurrence frequency by ≥75%. 2, 5
Recommended suppressive regimens:
- Valacyclovir 1 g orally once daily (or 500 mg once daily for patients with <10 recurrences/year) 2, 6
- Acyclovir 400 mg orally twice daily 2
- Famciclovir 250 mg orally twice daily 2
After 1 year of continuous suppressive therapy, discontinue to reassess recurrence frequency. 1, 5
Special Populations
HIV-Infected Patients
HIV-infected patients require closer monitoring and may need longer treatment courses. 1 For recurrent orolabial or genital herpes in HIV-infected patients, famciclovir 500 mg twice daily for 7 days is comparable to acyclovir 400 mg five times daily. 7
Severe Disease or Immunocompromised Patients
For severe mucocutaneous disease, disseminated infection, or complications requiring hospitalization, use IV acyclovir 5-10 mg/kg every 8 hours for 5-7 days or until clinical resolution. 1, 8
Monitor renal function at initiation and once or twice weekly during IV treatment, adjusting dose for renal impairment. 8 Ensure adequate hydration to prevent crystalluria and obstructive nephropathy. 8
Acyclovir-Resistant HSV
If lesions do not begin to resolve within 7-10 days of therapy, suspect acyclovir resistance. 5 This is more common in immunocompromised patients with prolonged or repeated antiviral exposure. 9
For proven or suspected acyclovir resistance, use foscarnet 40 mg/kg IV every 8 hours. 5 Alternative options include topical trifluridine (if lesions are accessible) or IV cidofovir for refractory cases. 9
Critical Pitfalls to Avoid
- Never use topical acyclovir—it is substantially less effective than oral therapy and is not recommended. 1, 2, 5
- Do not use standard genital herpes dosing (200 mg five times daily) for proctitis—the higher dose (400 mg five times daily) is specifically indicated. 1
- Avoid valacyclovir 8 g/day in immunocompromised patients due to risk of hemolytic uremic syndrome/thrombotic thrombocytopenic purpura. 5
- Ensure weight-based dosing for IV therapy (5-10 mg/kg every 8 hours) rather than fixed dosing. 8
Patient Counseling
Patients must understand that herpes is incurable and recurrent; antivirals control symptoms but do not eradicate the virus. 1, 2 Abstain from sexual activity when lesions or prodromal symptoms are present. 2, 5 Sexual transmission can occur during asymptomatic periods due to viral shedding, so inform partners and use condoms during all sexual exposures with new or uninfected partners. 2, 5