Evaluation of the relative efficacy of various antimalarial drugs in Nigerian children under five years of age suffering from acute uncomplicated falciparum malaria

Abstract

A parallel group-randomized comparison of the therapeutic efficacy of chloroquine (CQ), amodiaquine (AM), quinine (QN), sulphadoxine-pyrimethamine(S-P), mefloquine 15 mg kg⁻¹ (Ml5) and mefloquine 25 mg kg⁻¹(M25) in acute symptomatic uncomplicated falciparum malaria was carried out in 325 children under the age of five years in Ibadan, southwestern Nigeria, using the 28-day in vivo test. The parasitological cure rate, assessed only up to day 14, was 85% in the CQ group and 100% in the other groups. The mean parasite and fever clearance times were, respectively, 2·64 and 1·20 days in the CQ-sensitive subgroup, 2·32 and 1·13 days in the AM group, 2·27 and 1·17 days in the QN group, 2·23 and 1·76 days in the S-P group, 2·13 and 1·10 days in the M15 group, and 2·07 and 1·09 days in the M25 group. The CQ-treatment failures (seven of 46 patients) were successfully treated with 25 mg kg⁻¹ mefloquine, with parasite and fever clearance times of 1·73 and 1·0 days respectively.

The study shows that, in Nigeria, CQ is now less effective than AM, S-P, QN and M in acute falciparum malaria in the group most vulnerable to the infection (the under-five-year-olds). However, the fact that, in most of the CQ-treatment failures, there was an initial clinical response and a substantial reduction in parasite density, indicates that this drug still has a place as the drug of choice in uncomplicated falciparum malaria in the hyperendemic areas of West Africa, provided that the possibility of resistance is borne in mind and an alternative drug is immediately available for use in patients whose infection recrudesces after initial improvement.