Treatment of Herpes Simplex Virus (HSV) Infections
The recommended first-line treatment for HSV infections is valacyclovir 1000 mg three times daily for 7 days, acyclovir 800 mg five times daily for 7 days, or famciclovir 500 mg three times daily for 7 days. 1
Antiviral Therapy Options
First-line Treatments
- Valacyclovir: 1000 mg three times daily for 7 days
- Acyclovir: 800 mg five times daily for 7 days
- Famciclovir: 500 mg three times daily for 7 days
Treatment Duration
- Standard treatment duration is 7 days for immunocompetent patients
- For immunocompromised patients, treatment should continue until complete healing of lesions 1
Special Considerations
Timing of Treatment
- Treatment should be initiated within 72 hours of symptom onset for maximum effectiveness
- Some evidence suggests valacyclovir may still provide benefit when started after 72 hours 1
Renal Dose Adjustments
For patients with renal impairment, dose adjustments are necessary:
Valacyclovir adjustments:
| Creatinine Clearance (mL/min) | Dosing Adjustment |
|---|---|
| ≥50 (normal) | No adjustment needed |
| 30-49 | No adjustment needed |
| 10-29 | 500 mg every 24 hours |
| <10 | 500 mg every 24 hours |
Acyclovir adjustments:
| Creatinine Clearance (mL/min) | Dosing Adjustment |
|---|---|
| >25 | 800 mg every 4 hours, 5x daily |
| 10-25 | 800 mg every 8 hours |
| <10 | 800 mg every 12 hours |
Treatment by Patient Population
Immunocompromised Patients
- Higher doses may be required for immunocompromised patients
- For HIV-infected patients with CD4+ count ≥100 cells/mm³, higher doses of oral antivirals are recommended 1
- In the event of severe HSV disease during immunomodulator therapy:
- Initiate antiviral therapy
- Discontinue immunomodulators until symptoms improve 2
Pediatric Patients
- Valacyclovir is indicated for cold sores in patients ≥12 years
- Not established for genital herpes or herpes zoster in patients <18 years 3
- For children under 45 kg with herpes zoster, acyclovir 20 mg/kg body weight (maximum 800 mg/dose) orally 4 times daily for 7-10 days is recommended 1
Recurrent HSV Infections
- For patients with recurrent attacks, suppressive therapy should be considered:
- Aciclovir 400 mg twice daily
- Valaciclovir 500 mg daily
- Famciclovir 250 mg twice daily 2
Specific Clinical Scenarios
Ophthalmic HSV
- Requires ophthalmology consultation to prevent long-term vision loss
- Specialist review and advice should be sought for patients with prior HSV keratitis 2, 1
HSV Colitis
- Very rare even in IBD patients but can mimic acute relapse
- Should be excluded by immunohistochemistry or tissue PCR before increasing immunomodulator therapy 2
Severe or Life-Threatening HSV
- For severe systemic infections:
- Intravenous aciclovir or foscarnet
- Discontinuation of immunosuppressants
- Careful multidisciplinary management 2
Symptomatic Relief
- Topical 5% acyclovir cream applied 5 times daily for 4 days
- Topical anesthetics, warm sitz baths, oral analgesics
- Keep lesions clean and dry 1
Patient Education
- Apply medication at the first sign of prodrome
- Wash hands before and after application
- Continue treatment for the full prescribed duration even if symptoms improve
- Practice abstinence during outbreaks or prodromal symptoms
- Use condoms consistently to reduce transmission risk 1
Emerging Treatments
While not yet standard of care, helicase-primase inhibitors (amenamevir and pritelivir) are showing promise in clinical trials for treatment of HSV infections 4. Single-day high-dose regimens (such as famciclovir 1500 mg single dose for herpes labialis) have also shown effectiveness and may improve compliance 5.
Common Pitfalls to Avoid
- Delayed treatment: Initiating treatment after 72 hours significantly reduces efficacy
- Inadequate dose adjustments: Failure to adjust doses in renal impairment can lead to toxicity
- Premature discontinuation: Stopping treatment before the full course can lead to treatment failure
- Missing HSV colitis: Failing to consider HSV as a cause of refractory IBD can lead to inappropriate escalation of immunosuppression 2