Acyclovir in the management of herpes labialis

The efficacy of topical acyclovir in the treatment of herpes labialis has been evaluated in placebo-controlled trials with both the polyethylene glycol ointment and modified aqueous cream base preparations. Whereas a significant antiviral effect was demonstrated with acyclovir ointment in the two larger studies only favourable trends were demonstrated in the clinical parameters following early initiation of therapy. Significant clinical benefit was observed in a small single-centre study involving patients with frequent and generally more severe episodes of herpes labialis. In an animal model of experimental cutaneous herpes simplex virus infection acyclovir cream was found to be more effective than the ointment. This was confirmed in the first completed trial with acyclovir cream where a significant treatment effect was revealed on lesion duration and the inhibition of lesion development. Both topical preparations of acyclovir were well tolerated but acyclovir cream is to be preferred for the treatment of herpes labialis.