Idoxuridine in herpes zoster: further evaluation of intermittent topical therapy.

In a randomized double-blind controlled trial of the value of intermittent topical idoxuridine in treating herpes zoster in 118 patients idoxuridine 5% in 100% dimethyl sulphoxide (DMSO), applied four-hourly for four days, significantly shortened the vesicular phase, healing time, and duration of pain; idoxuridine 25% applied two-hourly produced no greater benefit. The only side effects were transient tender erythema in three patients and "urticarial" oedema in two patients with dermographia.