Valacyclovir: learn about side effects, dosage, special precautions, and more on MedlinePlus Valacyclovir is used to treat infections caused by certain types of viruses. Learn about side effects, drug interactions, dosages, warnings, and more. 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). Valaciclovir, also spelled valacyclovir, is an antiviral medication used to treat outbreaks of herpes simplex or herpes zoster (shingles). [2] It is also used to prevent cytomegalovirus following a kidney transplant in high risk cases. [2] Find patient medical information for Valacyclovir (Valtrex) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings 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. Herpes Zoster:Valacyclovir Tablets, USP are indicated for the treatment of herpes zoster (shingles) in immunocompetent adults. Valacyclovir hydrochloride, a prodrug of acyclovir, is rapidly absorbed following oral administration and almost completely converted to acyclovir andl-valine by first-pass intestinal and/or hepatic metabolism. VALACYCLOVIR (val ay SYE kloe veer) helps manage infections, such as cold sores, genital herpes, shingles, and chickenpox, caused by viruses. It will not treat colds, the flu, or infections caused by bacteria. Suppressive Therapy: Valacyclovir tablets, USP are indicated for chronic suppressive therapy of recurrent episodes of genital herpes in immunocompetent and in HIV-infected adults.