Valtrex (valacyclovir) is an antiviral drug that helps the body fight off the infection; it is prescribed to patients with cold sores, chickenpox, and genital herpes. It works by slowing down the spread of the herpes virus. Although Valtrex does not cure herpes it treats the symptoms and prevents the outbreaks. Before using this medicine you need to discuss with your doctor any allergies you have or used to have, as well as prescription or over-the-counter drugs you are currently taking. Valtrex may interfere with some of the medicines you are taking. DO not start taking any new drugs without telling your doctor about it. Before taking Valtrex, tell your doctor if you have HIV/AIDS, a weak immune system, kidney disease (or if you are on dialysis), or if you have had a kidney or bone marrow transplant. Valtrex needs to be used as soon as you feel the first symptoms – tingling, burning under the skin, appearance of tiny blisters. Herpes virus can be passed from an infected mother to the baby during childbirth. If you have genital herpes, it is very important to prevent herpes lesions during your pregnancy so that you do not have a genital lesion when your baby is born. Valtrex will not prevent the spread of herpes, which means you need to use a reliable method а protection.