Valacyclovir Dosing for HSV Flare-Ups
For episodic treatment of recurrent genital herpes flare-ups, take valacyclovir 500 mg twice daily for 5 days, starting at the first sign of prodrome or lesions. 1
Standard Episodic Treatment Regimens
The CDC provides multiple effective dosing options for treating HSV recurrences 1:
- Valacyclovir 500 mg twice daily for 5 days - This is the most convenient valacyclovir regimen 1
- Alternative acyclovir regimens include 400 mg three times daily, 200 mg five times daily, or 800 mg twice daily for 5 days 1
- Famciclovir 125 mg twice daily for 5 days is another alternative 1
Treatment should be initiated at the earliest sign of prodrome (tingling, itching, burning) or when lesions first appear to maximize effectiveness. 1, 2
First Episode vs. Recurrent Episodes
If this is a first clinical episode rather than a recurrence, higher dosing is required 1, 3:
- Valacyclovir 1 gram twice daily for 7-10 days for initial episodes 1, 3
- Treatment may be extended beyond 10 days if healing is incomplete 1, 3
- First episodes are typically more severe and require longer treatment duration 1
Special Populations Requiring Modified Dosing
HIV-Infected Patients
- For episodic treatment: Valacyclovir 1000 mg twice daily for 5 days (higher than immunocompetent dosing) 4
- For suppressive therapy: 500 mg twice daily for those with CD4+ count ≥100 cells/mm³ 3, 5
Renal Impairment
Dose adjustments are critical to prevent toxicity 2:
- CrCl 30-49 mL/min: No reduction needed for episodic treatment 2
- CrCl 10-29 mL/min: 500 mg every 24 hours 2
- CrCl <10 mL/min: 500 mg every 24 hours 2
- Hemodialysis patients: Administer dose after dialysis session 2
When to Consider Suppressive Therapy Instead
If you experience frequent recurrences (≥6 episodes per year), daily suppressive therapy may be more appropriate than episodic treatment 1:
- Valacyclovir 500 mg once daily for patients with ≤9 recurrences per year 1, 5
- Valacyclovir 1000 mg once daily for patients with ≥10 recurrences per year 1, 5
- Suppressive therapy reduces recurrence frequency by ≥75% 1, 5
Critical Timing Considerations
- Episodic therapy is most effective when started within 48 hours of symptom onset 3
- Patients should keep medication on hand to begin treatment immediately at first symptoms 1
- The 5-day treatment course should be completed even if symptoms resolve earlier 1
Treatment Failure and Resistance
If lesions persist after completing the full 5-day course 3, 5:
- Consider HSV resistance to acyclovir/valacyclovir 3, 5
- All acyclovir-resistant strains are also resistant to valacyclovir 3, 5
- Switch to IV foscarnet 40 mg/kg every 8 hours until clinical resolution for resistant cases 3, 5
Important Clinical Caveats
- Valacyclovir provides better bioavailability than acyclovir, allowing less frequent dosing 6, 7, 8
- The drug does not eliminate latent virus or prevent future recurrences after discontinuation 1
- Suppressive therapy reduces but does not eliminate asymptomatic viral shedding 1, 5
- Avoid doses of 8 grams per day in immunocompromised patients due to risk of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome 3, 5, 7