Chemosuppressive field trials in Thailand. IV. The suppression of Plasmodium falciparum and Plasmodium vivax parasitemias by mefloquine (WR 142,490, A 4-quinolinemethanol).

The effect of various dosages of mefloquine hydrochloride (WR 142,490) and sulfadoxine-pyrimethamine in the suppression of malaria infections was studied in an area of northeastern Thailand highly endemic for both chloroquine-resistant Plasmodium falciparum and for P. vivax. Both preparations, in all regimens studied, were effective in greatly reducing the incidence of falciparum infections. Mefloquine was more active in preventing vivax parasitemia than sulfadoxine-pyrimethamine; however, this combination remains the commercially available regimen of choice where both parasites occur and P. falciparum is resistant to chloroquine.