Oral acyclovir in the treatment of herpes zoster in general practice.

A double-blind, randomised trial evaluated the efficacy of oral acyclovir, 800 mg 5 times daily for 7 days, in acute herpes zoster and postherpetic neuralgia. Forty patients aged 16 years or over, presenting to their general practitioners within 3 days of rash onset, received acyclovir, while 43 patients received placebo. Acyclovir reduced the extent and duration of the rash, the spread of the rash to adjacent dermatomes and the incidence of disseminated lesions. It shortened the period of new lesion formation and reduced the incidence of ulceration. The weekly prevalence of pain was reduced on acyclovir by the fourth week, with a reduction in the monthly prevalence of chronic pain in the second and third months and a reduction in associated local neurological symptoms between months 3-6. Total analgesic use in the first 4 weeks was reduced by acyclovir, but during follow up there was no difference in the prevalence of analgesic use between groups. There were slightly fewer medical events on acyclovir in the second week, but the frequency was the same in each group for the rest of the 6 months. Biochemical and haematological tests showed no adverse effects of treatment.