Oral acyclovir suppression of recurrent genital herpes: a double-blind, placebo-controlled, crossover study.

A randomised, double-blind, placebo-controlled, crossover study was conducted in 31 male patients with a history of frequently recurrent genital herpes who received consecutively 200 mg acyclovir and matching placebo by mouth four times a day for 12 weeks each. During acyclovir therapy recurrences were completely prevented in 24 (77%) and were reduced in both frequency and duration in the remainder compared with those occurring during treatment with placebo. The incidence and nature of adverse events reported during each treatment period was virtually identical. No long-term effects on recurrence rates were discernible but chronic suppressive therapy can be considered to offer the means of controlling the severe forms of disease experienced by some patients.