Acyclovir cream is not efficacous in the acute phase of recurrent herpes labialis. A randomised controlled trial found that it was hardly any better when used prophylactically.
The drug is more effective against herpes simplex than varicella zoster, but must be started within an average of four hours of the first prodromal symptoms to reduce the median number of days of healing from six to four days. It may be the act of rubbing in a cream which helps healing more than the acyclovir.
Dosage - 5% cream apply five times a day for five days.
Alternatively, oral acyclovir can be given, e.g. 200 mg five times a day for five days. This has been shown to reduce pain and time loss of crusts, but not the time to complete healing.
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