Valacyclovir Dosing for Shingles Treatment
The recommended dose of Valtrex (valacyclovir) for treating shingles (herpes zoster) is 1 gram three times daily for 7 days. 1
Dosing Details and Administration
- Treatment should be initiated at the earliest sign or symptom of herpes zoster
- Most effective when started within 48 hours of the onset of rash 1
- Take with or without food 1
- Continue treatment until all lesions have completely crusted over 2
- If lesions are not completely crusted after the initial 7-day course, extending treatment is appropriate 2
Dosage Adjustments for Renal Impairment
Valacyclovir dosage must be adjusted based on creatinine clearance:
| Creatinine Clearance (mL/min) | Valacyclovir Dosing |
|---|---|
| ≥50 (normal) | No adjustment needed |
| 30-49 | No adjustment needed |
| 10-29 | 500 mg every 24 hours |
| <10 | 500 mg every 24 hours |
Clinical Evidence
The FDA-approved dosing of 1 gram three times daily for 7 days is based on clinical trials showing this regimen effectively treats herpes zoster. In a large comparative study, 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 acute herpes zoster symptoms. Importantly, valacyclovir alleviated zoster-associated pain and postherpetic neuralgia significantly faster than acyclovir 3.
A randomized, double-blind, multicenter study demonstrated that valacyclovir 1000 mg three times daily for 7 days significantly accelerated the resolution of herpes zoster-associated pain compared with acyclovir (median pain durations were 38 days versus 51 days for acyclovir) 4.
Alternative Dosing Regimens
Some research has explored alternative dosing regimens:
- Valacyclovir 1.5 g twice daily for 7 days has been studied and found to be safe and effective for uncomplicated herpes zoster in immunocompetent patients 5
- However, the FDA-approved regimen remains 1 gram three times daily for 7 days 1
Special Populations
Immunocompromised Patients
- Higher doses and longer treatment durations may be necessary
- Treatment should continue until complete healing of lesions 2
- For HIV-infected patients with CD4+ count ≥100 cells/mm³, higher doses of oral antivirals may be necessary 2
Children
- For children under 18 years, dosing is weight-based
- For chickenpox in immunocompetent children aged 2 to <18 years: 20 mg/kg three times daily for 5 days (not to exceed 1 gram three times daily) 1
Treatment Timing and Duration
- Initiate treatment at the earliest sign or symptom of herpes zoster 1
- Continue until all lesions are completely crusted over 2
- A 14-day regimen showed no significant advantage over the 7-day regimen in clinical studies 3
Important Considerations
- Patient should remain in isolation until all lesions are completely crusted over to prevent transmission 2
- Starting treatment later than 72 hours after rash onset may still provide benefit, but valacyclovir should ideally be given as soon as possible after symptoms appear 3
- Common side effects include nausea and headache 3
By following these dosing recommendations, patients with herpes zoster can experience faster resolution of symptoms and reduced risk of postherpetic neuralgia, significantly improving morbidity and quality of life outcomes.