Treatment of Herpes Simplex Virus Infections
Oral antiviral therapy with acyclovir, valacyclovir, or famciclovir is the cornerstone of treatment for herpes simplex virus (HSV) infections, with specific regimens depending on the type of infection, patient population, and whether it's a first episode or recurrence. 1
First-Line Treatment Options
First Clinical Episode:
- Acyclovir: 200 mg orally 5 times daily for 7-10 days 1
- Valacyclovir: 1 gram orally twice daily for 7-10 days
- Famciclovir: 250 mg orally three times daily for 7-10 days
Recurrent Episodes:
- Acyclovir:
- 200 mg orally 5 times daily for 5 days
- 400 mg orally 3 times daily for 5 days
- 800 mg orally twice daily for 5 days 1
- Valacyclovir: 500 mg orally twice daily for 3-5 days
- Famciclovir: 125 mg orally twice daily for 5 days
Orolabial Herpes:
- Oral valacyclovir, famciclovir, or acyclovir for 5-10 days 2
Special Populations
HIV-Infected Patients:
- Longer treatment courses required (7-14 days)
- Do not use short-course therapy (1-3 days) in HIV-infected patients 2
- For suppressive therapy in HIV patients, valacyclovir should be 500 mg twice daily 2
Immunocompromised Patients:
- For severe mucocutaneous lesions, start with IV acyclovir until lesions begin to regress, then switch to oral therapy 2
- Continue therapy until lesions have completely healed 2
- Longer treatment duration and closer monitoring required 1
Pregnant Women:
- Acyclovir is the first choice due to its established safety profile during pregnancy 2, 1
- Episodic therapy can be offered during pregnancy, but suppressive therapy is not routinely used 2
Treatment of Acyclovir-Resistant HSV
- Suspect resistance if lesions don't begin to resolve within 7-10 days of therapy 2
- Obtain viral culture and susceptibility testing to confirm resistance 2
- Treatment of choice for acyclovir-resistant HSV is IV foscarnet 2
- Alternative options for external lesions:
- Topical trifluridine
- Cidofovir
- Imiquimod (may require 21-28 days or longer) 2
Suppressive Therapy
Consider daily suppressive therapy for patients with:
- Frequent recurrences (six or more per year)
- Severe recurrences
- Significant psychological distress from recurrences 2, 1
Suppressive therapy options:
- Acyclovir: Twice-daily regimen
- Valacyclovir: 500 mg twice daily (for HIV-infected patients)
- Famciclovir: Twice-daily regimen 2
Suppressive therapy reduces recurrence frequency by at least 75% 1
Dosage Adjustments for Renal Impairment
Adjust dosage based on creatinine clearance:
| Creatinine Clearance (mL/min) | Acyclovir 800 mg Adjustment |
|---|---|
| >25 | 800 mg every 4 hours, 5 times a day |
| 10-25 | 800 mg every 8 hours |
| 0-10 | 800 mg every 12 hours |
For other dosages, refer to specific adjustments based on renal function 1
Monitoring and Follow-up
- Re-examine patients 3-7 days after starting therapy to assess response 1
- Monitor renal function for patients on high-dose IV acyclovir at initiation and 1-2 times weekly 2
- If no improvement is seen, consider:
- Incorrect diagnosis
- Co-infection with another STI
- HIV infection
- Poor medication adherence
- Antiviral resistance 1
Common Pitfalls and Caveats
Not testing for other STIs: All patients diagnosed with HSV should be tested for other STIs, including HIV 1
Inadequate treatment duration: HIV-infected patients require longer courses of therapy (7-14 days) and should not receive short-course therapy 2
Missing acyclovir resistance: Consider resistance if lesions don't improve within 7-10 days of starting therapy 2
Overlooking renal function: Dose adjustment is necessary for patients with renal impairment 1
Inadequate pain management: For painful lesions, consider acetaminophen or NSAIDs for mild pain, and gabapentin, pregabalin, or tricyclic antidepressants for moderate to severe pain 1