Valacyclovir Dosage for Reemergence of Shingles
For reemergence of shingles (herpes zoster), the recommended dosage of Valtrex (valacyclovir) is 1 gram 3 times daily for 7 days. 1
Rationale and Timing
The FDA-approved dosing for herpes zoster clearly specifies this regimen, and therapy should be initiated at the earliest sign or symptom of herpes zoster. Treatment is most effective when started within 48 hours of the onset of rash 1. However, observational data suggests that starting treatment later than 72 hours after rash onset may still provide benefit in reducing zoster-associated pain 2.
Administration Details
- Take valacyclovir without regard to meals
- Complete the full 7-day course even if symptoms improve
- Maintain adequate hydration during treatment
Dosage Adjustments for Renal Impairment
Renal function should be assessed before initiating therapy, as dosage adjustments are necessary for patients with impaired renal function:
| Creatinine Clearance (mL/min) | Dosing Adjustment |
|---|---|
| ≥50 (normal) | No adjustment needed |
| 30-49 | No adjustment needed |
| 10-29 | 1 gram every 24 hours |
| <10 | 500 mg every 24 hours |
Clinical Evidence
The recommended dosing regimen is supported by multiple clinical trials. A large comparative study demonstrated that valacyclovir 1000 mg three times daily for 7 days was at least as effective as acyclovir (800 mg five times daily for 7 days) in controlling the symptoms of acute herpes zoster 3. Importantly, valacyclovir significantly accelerated the resolution of zoster-associated pain and postherpetic neuralgia compared to acyclovir 3.
A follow-up study confirmed that a 14-day regimen of valacyclovir showed no significant advantage over the 7-day regimen 2, supporting the standard 7-day course.
Monitoring and Follow-up
- Monitor for clinical response within 72 hours of initiating therapy
- Follow up until complete resolution of lesions
- Watch for potential complications such as secondary bacterial infection
- Monitor for neurological symptoms (confusion, agitation, hallucinations) which may indicate neurotoxicity
Treatment Failure Considerations
If lesions persist after 7-10 days of therapy, consider the possibility of acyclovir-resistant HSV 4. In such cases, alternative treatments may be necessary.
Symptomatic Relief
While taking valacyclovir, the following measures can help provide symptomatic relief:
- Keep lesions clean and dry
- Use topical anesthetics for pain relief
- Take oral analgesics as needed for pain
- Consider sitz baths with warm water for comfort
Important Considerations
The twice-daily dosing regimen (1.5 g twice daily) has been studied and shown to be effective 5, but the FDA-approved regimen remains 1 gram three times daily 1.
For immunocompromised patients, particularly those with HIV, longer treatment courses may be necessary until lesions have completely healed 4.
The recommended dosage for reemergence of shingles is different from the dosage for other herpes virus infections such as genital herpes or cold sores 1.