THE SAFETY AND EFFICACY OF AMOCARZINE IN AFRICAN ONCHOCERCIASIS AND THE INFLUENCE OF IVERMECTIN ON THE CLINICAL AND PARASITOLOGICAL RESPONSE TO TREATMENT

One hundred men from a forest area of Ghana, without vector control or ivermectin distribution, were randomized to receive a single dose of ivermectin (150 mu g/kg body weight) on day 1 followed by amocarzine ( 3 mg/kg twice daily after meals) on days 8, 9 and 10 (34 patients), th e ivermectin alone (33 patients) or the amocarzine alone (33 patients) . Detailed clinical and laboratory examinations were made before, duri ng and after drug administration. On day 120, all palpable nodules wer e excised, fixed, sectioned, stained and examined by two blinded obser vers and the results compared with those for nodules from untreated co ntrols. Mazzotti-type reactions, such as itching, rash, peripheral sen sory phenomena and swellings, were more severe or frequent with amocar zine than ivermectin. Pretreatment with ivermectin markedly suppressed these reactions to amocarzine but did not affect other manifestations such as dizziness and gaze-evoked nystagmus. Ocular effects were mino r in all groups. Ivermectin produced minor macrofilaricidal effects on the adult male worms, marked degeneration of intra-uterine embryos, a nd potent microfilaricidal effects and suppressed skin microfilariae. Amocarzine did not affect the male worms or the intra-uterine embryos, was a less potent microfilaricide and did not suppress skin microfila riae. The efficacy of ivermectin plus amocarzine was similar to that o f ivermectin alone. The present results do not support the findings fr om the Americas and show that amocarzine has no role in the treatment of onchocerciasis in Africa.