The three main drugs used to treat HSV are acyclovir, famciclovir, and valacyclovir. You may recognize them by their brand names though–Zovirax, Famvir, and Valtrex. To prevent recurrent outbreaks of genital herpes the Mayo Clinic lists the following dosing guidelines.
Acyclovir: Adults and children 12 years of age and older—200 to 400 mg two to five times a day for five days or up to twelve months, depending on how often your outbreaks of infection occur.
Famciclovir: Adults—250 milligrams (mg) two times a day for up to one year.
Valacyclovir: Adults—500 milligrams (mg) or 1000 mg once a day.
I hope this helps.