What is the as-needed dosage and use of Valtrex (valacyclovir) for recurrent genital herpes outbreaks?

Valtrex (Valacyclovir) As-Needed Dosing for Recurrent Genital Herpes

For recurrent genital herpes outbreaks, take valacyclovir 500 mg twice daily for 3-5 days, starting at the first sign of symptoms (tingling, itching, or burning). 1, 2

Episodic Treatment Dosing

Standard Regimen

• Valacyclovir 500 mg twice daily for 3-5 days is the CDC-recommended episodic treatment for recurrent genital herpes 1, 2
• The FDA label specifies 3 days of treatment, while CDC guidelines recommend 5 days 1, 2
• Both 3-day and 5-day regimens are effective; the shorter 3-day course offers convenience while the 5-day course may provide additional symptom relief 1, 2

Alternative Once-Daily Dosing

• Valacyclovir 1000 mg once daily for 5 days is equally effective as 500 mg twice daily 3
• This once-daily option provides equivalent outcomes in terms of lesion healing, time to cessation of pain, and percentage of aborted episodes 3
• Once-daily dosing may improve adherence for patients who prefer simpler regimens 3

Critical Timing for Maximum Effectiveness

Initiate treatment during the prodromal phase or within 24 hours of lesion onset for optimal benefit 1

• Start at the earliest symptom: tingling, itching, burning, or the first appearance of lesions 1, 2
• Treatment is most effective when started within 48 hours of symptom onset 2
• Patients should keep medication on hand to enable immediate self-initiation of therapy 1

Efficacy Expectations

• Episodic valacyclovir reduces median episode duration to 4.0-5.0 days compared to longer durations with placebo 1
• The medication decreases pain associated with lesions and accelerates healing time 1
• Valacyclovir's enhanced oral bioavailability compared to acyclovir allows for less frequent dosing while maintaining effectiveness 1, 4

When to Consider Suppressive Therapy Instead

If you experience frequent recurrences, daily suppressive therapy may be more appropriate than episodic treatment:

• For patients with ≥6 recurrences per year: Consider switching to daily suppressive therapy, which reduces recurrence frequency by ≥75% 5
• Suppressive dosing options 5, 6, 2:
  • 500 mg once daily for patients with <10 recurrences per year
  • 1000 mg once daily for patients with ≥10 recurrences per year
  • 500 mg twice daily for HIV-infected patients with CD4+ ≥100 cells/mm³

Important Clinical Considerations

Treatment Failure

• If lesions do not begin to resolve within 7-10 days of appropriate therapy, suspect HSV resistance 5, 6
• All acyclovir-resistant strains are also resistant to valacyclovir 6
• IV foscarnet is the treatment of choice for resistant HSV 6

Renal Impairment

• No dose adjustment needed for creatinine clearance ≥30 mL/min 6
• Patients with substantial renal impairment require dose adjustment and monitoring 6

Administration

• Valacyclovir may be taken without regard to meals 2
• No laboratory monitoring is required for episodic treatment in immunocompetent patients 5

Safety Profile

• Valacyclovir is well tolerated at standard episodic dosing 1, 7
• Headache is the most commonly reported adverse effect 4
• High-dose valacyclovir (8 g/day) has been associated with thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in immunocompromised patients, but this has not been reported at doses used for episodic or suppressive HSV treatment 5, 4