There are three different brands of prescription herpes drugs: Valtrex, Famvir, and Zovirax. Valtrex is probably the most popular of the three. Each of the three prescription herpes drugs comes in tablet form, and is taken daily at the onset of a herpes infection, for a period of roughly two weeks. Prescription herpes drugs can also be taken constantly in an effort to avoid future outbreaks, though outbreaks can and do occur during this sort of preventive treatment. It is not absolutely necessary to treat herpes outbreaks as they will eventually clear on their own, though they'll clear much faster and with less discomfort when treatment is used.