Valacyclovir (Valtrex) Dosing Recommendations
For patients with genital herpes, cold sores, or shingles, valacyclovir dosing should be based on the specific condition being treated and adjusted according to renal function, with specific dosage reductions required for patients with creatinine clearance below 30 mL/min. 1, 2
Genital Herpes Dosing
First Episode
- 1 gram twice daily for 10 days 1
Recurrent Episodes
- 500 mg twice daily for 3-5 days (start within prodrome or within 2 days of lesion onset) 1, 3
- A 3-day course has been shown to be as effective as a 5-day course 3
Suppressive Therapy
- For patients with <10 recurrences per year: 500 mg once daily 1, 4
- For patients with ≥10 recurrences per year: 1 gram once daily or 500 mg twice daily 1, 4
- For HIV-infected patients: 500 mg twice daily 1, 2
Cold Sores (Herpes Labialis)
- 2 grams twice daily for 1 day (taken 12 hours apart) 2
- Start at earliest symptom (tingling, itching, burning) 2
Shingles (Herpes Zoster)
- 1 gram three times daily for 7 days 2
Dosage Adjustments for Renal Impairment 1, 2
| Creatinine Clearance | Genital Herpes Recurrent | Genital Herpes Suppressive | Cold Sores | Herpes Zoster |
|---|---|---|---|---|
| ≥50 mL/min (normal) | 500 mg every 12 hours | 1 gram every 24 hours | No reduction | 1 gram every 8 hours |
| 30-49 mL/min | No reduction | No reduction | No reduction | 1 gram every 12 hours |
| 10-29 mL/min | 500 mg every 24 hours | 500 mg every 24 hours | 500 mg every 24 hours | 1 gram every 24 hours |
| <10 mL/min | 500 mg every 24 hours | 500 mg every 24 hours | 500 mg every 24 hours | 500 mg every 24 hours |
Hemodialysis Patients
- Administer the recommended dose after hemodialysis sessions 2
- Approximately one-third of acyclovir is removed during a 4-hour hemodialysis session 2
Peritoneal Dialysis
- No supplemental doses required following CAPD or CAVHD 2
Clinical Considerations and Monitoring
Efficacy Considerations
- Valacyclovir provides better bioavailability than oral acyclovir, allowing less frequent dosing 5
- Once-daily regimens of valacyclovir offer a useful option for patients requiring suppressive therapy 4
- For episodic treatment, starting therapy at the earliest symptoms provides maximum benefit 1
Safety Monitoring
- Monitor renal function before starting therapy, especially with high doses 1
- Ensure adequate hydration during treatment, particularly with IV formulations 1
- Watch for neurological symptoms (confusion, agitation, hallucinations) which may indicate neurotoxicity 1
- A thrombotic microangiopathy-like syndrome has been reported in immunocompromised patients receiving high-dose valacyclovir (8 g/day) for prolonged periods 5
Patient Education
- Advise abstaining from sexual activity while lesions are present 1
- Counsel about natural history of disease, potential for recurrent episodes, and risk of viral transmission 1
- Encourage condom use during all sexual exposures 1
- Explain that suppressive therapy reduces but does not eliminate asymptomatic viral shedding 6
Special Populations
HIV-Infected Patients
- Higher doses are recommended: 500 mg twice daily for suppressive therapy 1, 2
- Don't use short-course therapy (1-3 days) in HIV-infected patients 1
- Treatment may be extended if healing is incomplete after 10 days 1
Pregnancy
- Acyclovir has the most reported experience in pregnancy and appears to be safe, making it the first choice for therapy of HSV infections during pregnancy 1
By following these dosing guidelines and adjusting for renal function, valacyclovir can effectively manage genital herpes, cold sores, and shingles while minimizing adverse effects.