What antiviral medice I need to take for upper lip herpes before hair laser removal treatment?

Treating skin for hair removal with laser can induce an outbreak episode of herpes simplex virus in the lip. I know that in some clinics, the nurse ask you to take an antiviral medicine one day before the treatment. Does anybody knows what medicine and what amout? I found this page with some information but is still not complete clear, see the part of oral medications: http://www.medicinenet.com/herpes_simplex_infections_non-genital/page6.htm