Valacyclovir (Generic Valtrex®) and acyclovir (Generic Zovirax®) are very similar drugs that treat the herpes simplex virus. Both show similar effectiveness against the herpes virus, you just need to take more acyclovir, more often, than you do valacylovir. For many patients, acyclovir may need to be taken up to 5 times daily depending on the infection being treated. Valacyclovir, on the other hand, may only need to be taken up to 2 or 3 times daily.