Thirty-eight patients with onchocerciasis who were treated with diethylcarbamazine (DEC) were entered into one of two randomized double-blind studies using indomethacin or cyproheptadine, or their matching placebos, in order to try to alleviate the reactions to treatment. Twenty patients received cyproheptadine (or placebo) in a dose of 4 mg three times daily for eight days, starting one day prior to DEC therapy. The remaining patients received indomethacin, 25 mg (or placebo) two capsules initially and then four further doses of 25 mg over the next 36 hours. The reactions to treatment were quantified using a recently described scoring system.DEC reduced the microfilarial skin snip count by 96–98% in all treatment groups and treatment with indomethacin or cyproheptadine did not interfere with the microfilaricidal action of DEC.Neither cyproheptadine nor indomethacin apparently reduced the severity of the reactions following the use of DEC in patients with onchocerciasis. We conclude that release of prostaglandins, histamine and serotonin are not primarily involved in the production of the Mazzotti reaction.

Fifteen patients with rheumatoid arthritis received indomethacin in three treatment schedules; indomethacin retard 75 mg twice daily; indomethacin capsules 50 mg three times daily; and indomethacin 100 mg suppository at night with 50 mg by mouth each morning. The study was a double-blind, double-dummy one with each treatment being given for 2 weeks after a washout period of 3 days. After the washout period, and at the end of each 2 week active treatment period, blood samples were taken during a dosage interval for assay of indomethacin concentrations in plasma. Clinical assessments were also performed. All three treatment period produced significant clinical improvements in the assessments compared with the placebo washout period. However, no differences were seen between the treatments. Side effects occurred with equal frequency in all three periods, and the anticipated reduction in central nervous system side effects during the indomethacin retard period was not seen. Plasma concentrations of indomethacin were significantly higher during indomethacin retard therapy with a peak concentration of 2500 +/- 25 ng ml-1 during indomethacin retard therapy (mean +/- s.d.) and 1900 +/- 200 ng ml during conventional oral therapy. Indomethacin retard is as effective as the other formulations of indomethacin but appears to offer no significant advantages.