Double blind study on efficacy and safety of single doses of ivermectin and diethylcarbamazine for treatment of Polynesian Wuchereria bancrofti carriers. Results at six months.

In 1989, a double-blind trial was implemented in Tahiti to compare both efficacy and tolerability of single doses of ivermectin and diethylcarbamazine (DEC) for treatment of Wuchereria bancrofti carriers. Of 58 carriers, in whom microfilarial (mf) density was greater than or equal to 100 mf/ml, 23, 24 and 11 were randomly allocated to treatment with respectively ivermectin 100 mcg/kg, DEC 3 and DEC 6 mg/kg. One week after treatment, clearance of microfilaremia was complete in 22 of the 23 carriers treated with ivermectin and in one only of the 35 treated with DEC. Adjusted geometric mean for mf densities was significantly lower (p less than 0.001) in carriers treated with ivermectin than in those treated with DEC at one, but neither at 3 (p = 0.26) nor at 6 months (p = 0.63). At 3 and 6 months, mf levels were 14 and 28%, 21.6 and 19.4%, and 10.2 and 8.4% of pretreatment mf levels in carriers treated respectively with ivermectin 100 mcg/kg, DEC 3 and DEC 6 mg/kg. Side effects were experienced by 51 carriers (88%) of whom only 8 (14%) suffered a grade 3 reaction. Onset and intensity of side effects were significantly associated (p less than 0.01) with both pretreatment mf densities and peripheral blood parasite clearance. Efficacy of ivermectin single dose was superior to that of DEC single dose in terms of immediate mf clearance but not in terms of sustained mf decrease at 6 months.