Valtrex (valacyclovir) is a very effective medication which is actually transformed into the active form of the drug once it is inside of your body. This is excellent, because it helps to decrease the side effects that the drug has on other parts of your body. Valcyclovir is even more specific than other such "pro-drugs" as they are called, because the full conversion to the active form of the drug only occurs in the presence of the virus that it targets. That being said, any drugs can have side effects (although acne
is not necessarily a common side effect of valcyclovir). If you notice that you are having a change in your skin, it could be related to the medication. Skin changes are very common side effects, but acne on the back is also common in and of itself. The key in your situation will be speaking with your doctor
and determining whether or not the acne is likely to be from the drug, and whether or not the risks of discontinuing the drug are better than continuing the drug despite the potential that it is causing your back acne. Please speak with your doctor about your questions and symptoms.