Mefloquine-pyrimethamine-sulfadoxine combination delays emergence of mefloquine resistant Plasmodium falciparum in continuous culture.

The efficacy of mefloquine against Plasmodium falciparum in continuous culture was studied. The development of mefloquine resistance in P. falciparum was significantly inhibited by a combination of mefloquine, pyrimethamine and sulfadoxine. By contrast, more resistant variants were selected in continuous culture without drug pressure or with pyrimethamine-sulfadoxine pressure. The most mefloquine resistant variants were selected by step-wise increases in mefloquine pressure.