High-dose intravenous acyclovir in the treatment of zoster: a double-blind, placebo-controlled trial

In a randomised, double-blind, controlled trial, 40 patients with zoster of short duration (rash present for less than three days) were given either 10 mg/kg acyclovir (20) or placebo (20) intravenously three times daily for five days. Pain was reduced in the treatment group both in the acute phase and at follow-up, when compared with the placebo group, but this difference did not reach statistically significant levels. Healing of the lesions was also better, but not significantly so, in the acyclovir group. No complications of the disease were seen in the six cases of ophthalmic zoster given acyclovir whereas, of the four cases in the placebo group, two developed seventh cranial nerve palsies and one secondary glaucoma. No evidence of renal or other major toxicity was detected in the acyclovir group, although three patients developed mild thrombophlebitis. We conclude that acyclovir, given by the route and in the dose and frequency as used in this study, is free from major side effects, but is only of marginal benefit in the treatment of zoster.