The in vitro response of Plasmodium falciparum to amodiaquine, quinine and quinidine in Tanga region, Tanzania.

The in vitro response of P. falciparum to amodiaquine, quinine and quinidine was assessed in Tanga region where chloroquine resistance is established, to determine baseline susceptibility levels which could guide health care deliverers on the suitability of these drugs for the treatment of falciparum malaria in the areas studied. Amodiaquine resistance was observed in all of the three areas. 16.7%, 24.0% and 14.7% of successful in vitro tests showed resistance to amodiaquine in Korogwe, Muheza and Tanga respectively. The in vitro response to quinine and quinidine showed that P. falciparum strains in the three areas are very sensitive to the two drugs. Only 1.9%, 4.5% and 1.4% of successful quinine tests showed resitance in Korogwe, Muheza and Tanga respectively. Quinidine showed activity which is twice higher than that of quinine and only 1 isolate in Tanga showed resistance response to quinidine.