More recently, docosanol has been approved by the Food and Drug Administration (FDA) as a pharmaceutical antiviral agent^[6] for reducing the duration of cold sores caused by the herpes simplex virus in the OTC medication Abreva.^[7]

Docosanol is thought to act by inhibiting the fusion of the human host cell with the viral envelope of the herpes virus, thus preventing its replication. This mechanism has not been demonstrated empirically.^{[citation needed]}

The drug was licensed as an oral herpes medicine after clinical trials by the FDA in July 2000.^[8] It was shown to shorten the healing by 17.5 hours on average (95% confidence interval: 2 to 22 hours) in a placebo-controlled trial.^[9] Another trial showed no effect when treating the infected backs of guinea pigs.^[10]

Marketed by Avanir Pharmaceuticals, Abreva was the first but not the only over-the-counter antiviral drug approved for sale in the United Statesand Canada. In Europe, it is marketed by Healthcare Brands under the name Erazaban. In the UK it is known by the name "Blistex Cold Sore Cream". In March 2007 it was the subject of a US nationwide class-action suit against Avanir and GlaxoSmithKline as the claim that it cut recovery times in half was found to have been misleading in a California court, but the case was eventually settled and the "cuts healing time in half" claim had not been used in product advertising for some years.^[11]