Chemotherapy of onchocerciasis: a controlled clinical trial of topical diethylcarbamazine (DEC) in Guatemala.

A double-masked, controlled clinical trial was conducted in Guatemala to assess the safety and efficacy of diethylcarbamazine (DEC) lotion as compared to placebo lotion in the treatment of onchocerciasis. One hundred eighty-seven people were enrolled in this study and were followed for two months. Lotion was applied daily for seven days, then weekly for seven weeks. The decrease in mean microfilarial counts per skin snip was significantly greater in those receiving DEC lotion than for those receiving placebo lotion. The proportionate reduction in microfilarial counts was similar for people with light, moderate, or heavy microfilarial loads. Side effects were mainly related to skin changes, fever, and malaise, and occurred in nearly one-third of the people receiving DEC lotion. These reactions occurred almost as commonly in those people who were lightly infected as in those who had moderate or heavy infections.