[A topical solution of 40% idoxuridine in dimethyl sulfoxide compared to oral acyclovir in the treatment of herpes zoster. A double-blind multicenter clinical trial]

Background: Both topical 40% idoxuridine in dimethylsulfoxide (IDU) and oral acyclovir (ACV) are useful in herpes zoster (HZ). This is the first clinical trial which compares the efficacy of both drugs in the course of the disease and in the prevention of post-herpetic neuralgia (PHN).
Methods: Patients of both sexes older than 18 years, with a HZ of less than 4 days were selected. Patients with otic or ophthalmic zoster, serious concomitant illness or pregnant or breast-feeding women were excluded. Following a double dummy design, the patients received at random topical IDU and oral placebo, or oral ACV and topical placebo. Topical treatment was applied during 4 days and oral treatment during 7 days. The evolution of the disease (number of individual lesions, evolution of symptoms, use of analgesic drugs and eventual appearance of complications) was controlled on days 0, 2, 4, 6, 8, and weekly until its resolution.
Results: The group of patients treated with IDU (85) showed a better evolution of the disease than those treated with ACV (86) in some of the parameters controlled: day of first and all vesicles drying (p less than 0.05), last day of moderate-intense pain (p less than 0.05), hyperaesthesia (p less than 0.05) and itching (p less than 0.05) and last day of analgesic use (p less than 0.01). The appearance of new vesicles during treatment was lower in the IDU treated group (p less than 0.01). A tendency favouring IDU can be observed in the appearance of PHN.
Conclusions: In our study topical 40% idoxuridine in DMSO was better than oral acyclovir in 7 of the 14 clinical parameters studied.