A community trial of ivermectin for onchocerciasis in Sierra Leone: adverse reactions after the first five treatment rounds

Abstract

We have studied the adverse reactions reported after ivermectin in 1745 villagers in southern Sierra Leone, allocated at random to receive ivermectin or placebo and treated 'double-blind' with 4 doses at six-monthly intervals. Six months after the fourth dose all eligible villagers received ivermectin regardless of their previous treatment. At the first treatment round more adverse reactions were reported by villagers treated with ivermectin than by those who received placebo. Reactions occurred most often on the second day after treatment. There were significant correlations between an individual's skin microfilarial load and the risk of developing adverse reactions. On re-treatment there was no significant excess of reported adverse reactions in the ivermectin group compared to the placebo group. Unlike other adverse reactions, the risk of cutaneous reactions after the first dose of ivermectin was not correlated with skin microfilarial load. In addition, after re-treatment with ivermectin, cutaneous reactions were reported significantly more often than with placebo. We confirm that ivermectin is safe for mass distribution, but adverse reactions should be monitored and treated after the first dose. Throughout this study ivermectin was well tolerated, with significantly more villagers returning for re-treatment after ivermectin than placebo, and all adverse reactions were self-limiting or successfully managed with symptomatic treatment. We question whether strict clinical monitoring should be routine at re-treatment, when only cutaneous reactions were consistently reported. If clinical monitoring could be used more selectively, distribution campaigns might be easier to manage and more cost-effective.

Adverse Reactions to Ivermectin Treatment in Simulium Neavei–transmitted Onchocerciasis

“…In our study population, the frequency of adverse reactions after ivermectin treatment was much higher (59%) than that reported in other similar studies: De Sole and others found a rate of 9% for adverse reactions to ivermectin in their trial in Ghana, 6 while Whitworth and others reported 28% of the patients with adverse reactions after ivermectin treatment in Sierra Leone. 4 In Liberia, it was found that the rate of adverse reactions was quite low, ranging between 0.6% and 1.3%. 5 One explanation for the much higher occurrence of adverse reactions after ivermectin treatment in Kigoyera parish could be that the community microfilarial load (CMFL) was much lower in Ghana, where only 4.9% of the villages had a CMFL higher than 35 mf/skin snip, while in our eight villages, the CMFL was always greater than 35 mf/skin snip, with an average CMFL of 79 mf/skin snip (range ‫ס‬ 39−128 mf/skin snip).…”

“…Adverse reactions were generally rare and associated with the microfilaria density in the skin. 4,6,7 All of the studies on adverse effects of ivermectin have been carried out in areas of the Onchocerciasis Control Program (OCP) in west Africa, where Simulium damnosum s.l. is the transmitting vector.…”

The Role of P-glycoprotein in Preventing Developmental and Neurotoxicity

“…It is estimated that nearly 20 million people are infected and another 85 million are at risk. Large and diverse populations have been treated with ivermectin in Africa (Burnham, 1993;Chijioke and Okonkwo, 1992;Chippaux et al, 1993;De Sole et al, 1989a,b;Doumbo et al, 1992;Gardon et al, 1997;Ogunba and Gemade, 1992;Pacque et al, 1990Pacque et al, , 1991Whitworth et al, 1991), Polynesia (Cartel et al, 1992), and Latin America (Collins et al, 1992). Typical human doses range from 0.1 to 0.2 mg/kg (FAO/WHO, 1993).…”

Neglected Tropical Diseases: Treatment of Dermatological Manifestation of Filariasis with Combination Regimen of Albendazole, Ivermectin, and Loratadine: A Case Report from a Suburban Community in Nigeria

“…Though effective, the drugs contribute significantly to severe adverse effects in up to 70% of patients [11,12]. This may be attributed to the action of the drug or the ensuing death of parasites after the administration of the drug.…”