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. Find patient medical information for Valacyclovir (Valtrex) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Herpes Zoster:Valacyclovir Tablets, USP are indicated for the treatment of herpes zoster (shingles) in immunocompetent adults. 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 is used to treat infections caused by certain types of viruses. Learn about side effects, drug interactions, dosages, warnings, and more. Valacyclovir is a weak CYPA2 inhibitor and may increase drug levels of medications metabolized by this enzyme, such as: clozapine, tizanidine and theophylline derivatives Detailed Valacyclovir dosage information for adults and children. Includes dosages for Herpes Simplex Labialis, Herpes Simplex - Suppression, Herpes Zoster and more; plus renal, liver and dialysis adjustments. 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. 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] Valacyclovir: learn about side effects, dosage, special precautions, and more on MedlinePlus.