A topic in Clinical Evidence summarizes the results of one non-systematic review (5 RCTs, 650 people) and one subsequent RCT. The review found that aciclovir reduced the duration of viral shedding and duration of lesions compared with placebo (5 days with aciclovir vs 6 days with placebo). The subsequent RCT (n=131) found that aciclovir 800 mg 3 times daily for 2 days reduced the duration of lesions, episodes, and viral shedding compared with placebo (duration of lesions 4 days vs 6 days, duration of episodes 4 days vs 6 days, duration of viral shedding 25 hours vs 58.5 hours). Oral famciclovir (1 RCT), and oral valaciclovir (1 RCT) significantly reduced the duration of lesions and viral shedding. There was no difference between valaciclovir vs aciclovir (1 RCT) and between 3 days and 5 days of valaciclovir (2 RCTs).