Docosanol: a topical antiviral for herpes labialis.

Recurrent herpes labialis is a painful and potentially disfiguring infection affecting an estimated 40 million people in the US alone. The majority of recurrences are caused by herpes simplex virus type 1. Various oral and topical formulations of nucleoside analogues have demonstrated efficacy for this indication. Over-the-counter treatments are palliative in nature and do not reduce time to healing. Docosanol is a compound with a unique mechanism of action involving viral fusion inhibition. In randomised, clinical trials, a 10% docosanol cream formulation, initiated within 12 h of symptoms onset, demonstrated efficacy in reduction of time-to-healing compared with a polyethylene glycol control. Despite its potential to be a mild irritant, this novel antiviral was well-tolerated in clinical trials. Docosanol is the first topical antiviral approved for over-the-counter use in recurrent herpes labialis.