Oral acyclovir for acute herpes zoster infections in immune-competent adults.

Previous studies have shown that intravenous acyclovir does modify rash development, reduce viral shedding and alleviate acute pain in herpes zoster. To assess the clinical efficacy of an oral dosage regimen with 800 mg acyclovir five times daily, double-blind, placebo-controlled studies were carried out at three centres within the U.K., using a common protocol. According to inclusion criteria (immune competent patients over 60 years of age with a clinical diagnosis of herpes zoster with rash of no more than 72 h duration, no previous systemic antiviral treatment, no history of renal insufficiency) 205 patients were recruited after they had given their informed consent. Patients were randomly assigned to receive either two 400 mg tablets acyclovir (41 men, 59 women) or matching placebo (46 men, 59 women) five times daily for seven days. Treatment was predominantly domiciliary based. According to clinical assessment and pain score acyclovir recipients showed a significant benefit in terms of reduction in rash progression if treatment was started within 48 h of the onset of rash, and alleviation of pain during the acute phase of herpes zoster. Overall, the number of patients developing extradermal lesions was significantly lower in the acyclovir group than in the placebo group (p = 0.02). However, there were no significant differences in rash progression and pain response in patients with herpes zoster affecting the ophthalmic division of the trigeminal nerve in patients who received acyclovir (n = 21) compared to those who received placebo (n = 32). 12 acyclovir and 13 placebo recipients reported symptoms, predominantly gastrointestinal in nature, possibly or probably related to therapy.(ABSTRACT TRUNCATED AT 250 WORDS)