Activity in vitro of chloroquine, cycloguanil, and mefloquine against African isolates of Plasmodium falciparum: presumptive evidence for chemoprophylactic efficacy in Central and West Africa.

Discussion Although multiresistant P. faldipamm is an increasing problem, reports of P . vivax resistant to chloroquine have been few. The above case reports document the presence of chloroquine-resistant P. vivax in India, and show that it may not be as rare as it i s presumed to be. Also, the number of drug resistant strains is probably increasing. Antimalarial drugs other than chloroquine used for P. vivax have limitations of their own: sulfadoxinepyrimethamine is not as effective as chloroquine, quinine is difficult to administer, and tetracyclines are contraindicated in children and pregnant women and are not tolerated by many patients. Non-availability and cost limits the use of mefloquine and halofantrine. Further population-based epidemiological studies will be needed to define the extent of chlofoquine resistant P. vivax and identify suitable alternative treatments. If this problem were to become widespread, there would be significant implications for the treatment and prophylaxis of malaria in India.