Valtrex is an antiviral drug

Valtrex is used to treat genital herpes, shingles, and cold sores.
Valtrex is an antiviral drug. It slows the growth and spread of the herpes virus.
Valtrex lessens the symptoms of these infections and shortens the length of time you are sick.
Valtrex may also be used for purposes other than those listed in this medication guide.

Take all of the Valtrex that has been prescribed for you even if you begin to feel better. Your symptoms may start to improve before the infection is completely treated.
Treatment with Valtrex should be started as soon as possible after the first appearance of symptoms (e.g. tingling, burning, blisters).
Herpes infections are contagious and you can infect other people, even during treatment. Avoid letting infected areas come into contact with other people. Wash your hands frequently to prevent transmission.