Valacyclovir Dosage and Treatment Plan for Herpes Simplex Virus Infections
For herpes simplex virus infections, valacyclovir should be dosed as follows: 2 grams twice daily for 1 day for cold sores, 1 gram twice daily for 10 days for initial genital herpes episodes, and 500 mg twice daily for 3 days for recurrent genital herpes episodes. 1
Dosing Recommendations by HSV Infection Type
Cold Sores (Herpes Labialis)
- Adults and children ≥12 years: 2 grams twice daily for 1 day (12 hours apart) 1
- Initiate at earliest symptom (tingling, itching, burning)
- Do not exceed 1 day of treatment
Genital Herpes
Initial Episode
- Recommended dose: 1 gram twice daily for 10 days 1
- Most effective when started within 48 hours of symptom onset
Recurrent Episodes
- Recommended dose: 500 mg twice daily for 3 days 1
- Initiate at first sign or symptom of an episode
Suppressive Therapy
- Normal immune function: 1 gram once daily 1
- Alternative for ≤9 recurrences/year: 500 mg once daily 1
- HIV-infected patients (CD4+ ≥100 cells/mm³): 500 mg twice daily 1
Reduction of Transmission
- For source partner with ≤9 recurrences/year: 500 mg once daily 1
Dosage Adjustments for Special Populations
Renal Impairment
Dosage adjustment is necessary based on creatinine clearance 1:
| Indication | Normal Dosage | CrCl 30-49 mL/min | CrCl 10-29 mL/min | CrCl <10 mL/min |
|---|---|---|---|---|
| Cold sores | 2g twice daily for 1 day | No reduction | 1g every 24 hours | 500mg every 24 hours |
| Genital herpes (recurrent) | 500mg every 12 hours | No reduction | 500mg every 24 hours | 500mg every 24 hours |
| Genital herpes (suppressive) | 1g every 24 hours | No reduction | 500mg every 24 hours | 500mg every 24 hours |
| Suppressive (≤9 recurrences/year) | 500mg every 24 hours | No reduction | 500mg every 48 hours | 500mg every 48 hours |
| HIV-infected patients | 500mg every 12 hours | No reduction | 500mg every 24 hours | 500mg every 24 hours |
Hemodialysis Patients
- Administer recommended dose after hemodialysis 1
- Approximately one-third of acyclovir is removed during a 4-hour hemodialysis session
Clinical Efficacy
Valacyclovir has demonstrated effectiveness in multiple clinical scenarios:
- Cold sores: Reduces duration when initiated at earliest symptoms 1
- Initial genital herpes: As effective as acyclovir (200 mg 5 times daily) with more convenient dosing 2
- Recurrent genital herpes: Reduces duration of viral shedding, hastens lesion healing, and decreases lesion-associated pain 3
- Suppressive therapy: Significantly prolongs time to recurrent episodes compared with placebo 4
- Transmission reduction: Reduces risk of HSV-2 transmission by 75% for symptomatic acquisition and 48% for overall acquisition 1
Advantages Over Acyclovir
Valacyclovir offers significant advantages over acyclovir:
- Better oral bioavailability (3-5 times higher acyclovir exposure) 5, 3
- Less frequent dosing (twice daily vs. five times daily) 2
- Comparable efficacy and safety profile 6
- Improved compliance due to simplified regimen 2
Important Clinical Considerations
- Initiate treatment at earliest signs/symptoms for optimal efficacy 1
- May be taken without regard to meals 1
- For patients unable to swallow tablets, an oral suspension can be prepared extemporaneously 1
- Monitor renal function in patients with known renal impairment 1
- Well tolerated with a safety profile similar to acyclovir or placebo 3
Valacyclovir represents an advance in antiherpes therapy with its convenient dosing regimen and established efficacy, making it an excellent first-line treatment option for herpes simplex virus infections.