Sensitivity of Plasmodium falciparum to amodiaquine and chloroquine in central Africa: a comparative study in vivo and in vitro.

A comparative study in vivo of amodiaquine efficacy (35 mg/kg over 3 d) and chloroquine (25 mg/kg over 3 d) was conducted in 1991 and 1992 in Cameroon and Congo in 123 patients with uncomplicated Plasmodium falciparum malaria. Amodiaquine was more effective than chloroquine, with parasite clearance by day 7 in 79.7% of the patients compared with 59.4%. Sixteen of 32 (50%) P. falciparum isolates tested in vitro were resistant to chloroquine and only 3 of 34 (9%) were resistant to amodiaquine. 5.3% of patients treated with amodiaquine complained of pruritus and 18.7% of nausea, compared with 15.7% and 5% respectively of those treated with chloroquine.