What is Valtrex (valacyclovir) used for?

Valtrex is a prescription medicine used to treat infections caused by the herpes virus. It is used to treat genital herpes and cold sores (caused by certain strains of herpes simplex viruses). It also treats herpes zoster (shingles) and chickenpox (caused by the varicella-zoster virus).

How does Valtrex (valacyclovir) work?

Valtrex blocks certain enzymes that viruses need to grow. This medication does not cure herpes infections. However, it decreases symptoms like pain and itching. It also helps sores to heal and prevents new sores from forming.  

What are Valtrex (valacyclovir) doses?

The Valtrex dose depends on the condition being treated.  

Cold sores: The usual dose of Valtrex in adults and children aged 12 or older is 2 grams twice a day for 1 day (the two doses are taken 12 hours apart). 

Genital herpes: The usual Valtrex dose in adults with genital herpes (initial episode) is 1 gram twice daily for 10 days. Recurrent genital herpes is treated with Valtrex 500 mg twice a day for 3 days. For suppression of recurrent episodes, doctors typically prescribe 500 mg to 1 gram once a day. 

Herpes zoster: The recommended dose of Valtrex for herpes zoster (shingles) in adults is 1 gram three times a day for 7 days. 

Chickenpox: The dose of Valtrex to treat chickenpox in children depends on the child’s body weight.