Levamisole in patients with recurrent herpes infection.

The effect of the immunomodulating drug levamisole was tested in 33 patients with frequently recurring attacks of herpes labialis or herpes genitalis. All patients had suffered monthly recurrent attacks for at least six months, but were otherwise healthy. Patients were randomly allocated to receive levamisole tablets, 2.5 mg/kg orally, on two consecutive days each week for 26 weeks, or placebo tablets taken for a similar time. The tablets were reversed for a second consecutive six-month period. Seven of 21 patients (33%) with recurrent herpes genitalis infection showed complete response and 10 (47%) showed a partial response while receiving levamisole. Three of 21 patients (14%) showed a partial response on placebo. Six of 12 patients (50%) with herpes labialis showed complete or partial responses, with three partial responses on placebo. Frequent minor drug side effects were seen, and therapy was ceased in one patient. No episodes of leucopenia or agranulocytosis were encountered. Levamisole produces a significantly better reduction in frequency, duration and severity of herpes attacks than placebo, particularly after the initial eight weeks of administration.