Valtrex®
valacyclovir · oral tablet
Antiviral
Approved uses
Herpes zoster, including herpes zoster ophthalmicus
1 gram three times daily for 7 days, started as early as possible and ideally within 72 hours of rash onset
The 72-hour window drives the urgency of the referral, not the dose
Cold sores (herpes labialis), age 12 and over
2 grams every 12 hours for one day
Genital herpes, initial or recurrent episode, and suppression
Per the label's regimen for the episode being treated
Contraindications
Valacyclovir is contraindicated in patients who have had a demonstrated clinically significant hypersensitivity reaction to valacyclovir, acyclovir, or any component of the formulation.
Available FormsOral tablet, valacyclovir hydrochloride caplets, 500 mg and 1 gram.
Mechanism of ActionInhibits viral DNA polymerase, preventing viral replication.
Warnings & Precautions
- Thrombotic thrombocytopenic purpura and haemolytic uraemic syndrome, some fatal, have occurred in advanced HIV disease and in transplant recipients at high doses.
- Acute renal failure and central nervous system effects, including confusion and hallucination, have been reported, more often in the elderly and in renal impairment; adjust the dose for renal function.
- Maintain adequate hydration.
Common Side Effects
The most common adverse reactions reported in at least 1 indication by greater than 10% of adult subjects treated with valacyclovir and observed more frequently than with placebo are headache, nausea, and abdominal pain. The only adverse reaction reported in greater than 10% of pediatric subjects was headache.
Pregnancy & LactationPregnancy: Available data from the pregnancy registry over decades have not identified a drug-associated risk of major birth defects.
Lactation: Acyclovir is present in human milk after valacyclovir dosing; consider the mother's clinical need.
Pediatric UseNo studies