Medscape - Herpes simplex, zoster-specific dosing for Valtrex (valacyclovir), frequency-based adverse effects, comprehensive interactions, contraindications, pregnancy & lactation schedules, and. Valtrex (valacyclovir) is a prescription medication used to treat viral infections such as genital herpes, cold sores (fever blisters), and shingles. Valtrex dosages depend on what you’re taking it for, your age, and if you have kidney problems. Valtrex is an antiviral drug. It slows the growth and spread of the herpes virus to help the body fight the infection. Valtrex is used to treat infections caused by herpes viruses, including genital herpes, cold sores, and shingles (herpes zoster) in adults. Overview: Valacyclovir is an antiviral medicine used to treat conditions such as cold sores, genital herpes, shingles, and chickenpox. It works by stopping the growth of herpes viruses. Common. It is marketed by GlaxoSmithKline under the brand names Valtrex [1] and Zelitrex. Valaciclovir has been available as a generic drug in the US since November 2009. Valtrex (Valacyclovir Hydrochloride) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources. Valtrex is a nucleoside analogue DNA polymerase inhibitor used for the treatment of viruses including cold sores, genital herpes, shingles and chickenpox. Valacyclovir is used to treat cold sores (herpes labialis), shingles (herpes zoster), and genital herpes. It is also used to control genital herpes outbreak in patients with human immunodeficiency virus-1 (HIV-1). This medicine is also used to treat cold sores and chickenpox in children. Valacyclovir (Valtrex) is an antiviral medication used for treating infections caused by herpes simplex virus and varicella zoster virus, such as cold sores, genital herpes, and shingles, and chickenpox. Valacyclovir is an antiviral drug. It slows the growth and spread of the herpes virus to help the body fight the infection. Valacyclovir is used to treat infections caused by herpes viruses, including genital herpes, cold sores, and shingles (herpes zoster) in adults.