Valtrex (valacyclovir) is a highly-efficient antiviral drug primarily intended for the treatment of the herpes virus. It works by stopping the spread of the virus and lessening the symptoms of an infection. It's best to start the treatment with the very first appearance of tingling, burning, and blisters, as this way Valtrex is going to be most efficient. You are contagious even if you are taking Valtrex, and still need to use protection while having sex. Make sure you talk to your doctor about your health conditions, such as kidney disease, weak immune system, a history of kidney or bone marrow transplant, and HIV/AIDS, as they may potentially affect the dose you will be prescribed. You do not have to report to your doctor the following side effects that are considered to be mild and are not expected to get worse with time: dizziness, headache, stomach pain, stuffy nose, depression, joint pain, nausea, sore throat, and mild skin rash. These side effects will most probably disappear on their own without any need for your doctor to intervene. Although there is no risk for the unborn baby when Valtrex is taken by a pregnant woman, it may still pass into breast milk and affect the health of an unborn baby. Discuss your pregnancy or breastfeeding with your health care provider before taking Valtrex.