Chloroquine versus Sulfadoxine-Pyrimethamine for Treatment of Plasmodium falciparum Malaria in Savannakhet Province, Lao People's Democratic Republic: An Assessment of National Antimalarial Drug Recommendations

The in vivo efficacies of the Lao People's Democratic Republic (Laos) nationally recommended antimalarial agents—chloroquine and sulfadoxine-pyrimethamine—were assessed in a randomized, comparative trial that involved 100 patients with uncomplicated Plasmodium falciparum malaria who were followed for 42 days after starting treatment. Despite a shorter mean time to fever clearance associated with administration of chloroquine (mean time to clearance, 35.6 h; 95% confidence interval [CI], 26.3–45.0 h), compared with that associated with sulfadoxine-pyrimethamine (61.1 h; 95% CI, 50.9–71.3 h; P < .001), treatment failures were twice as frequent among patients receiving chloroquine therapy than among those receiving sulfadoxine-pyrimethamine therapy (36% vs. 18%; P = .02). Of 23 treatment failures, 10 (43%) were high grade. Treatment failure rates among children (age range, 5–15 years) were 4.9 times higher (95% CI, 2–12) than those among adults (P < .0001). Gametocytemia after antimalarial treatment was associated with receipt of sulfadoxine-pyrimethamine therapy and with treatment failure (P = .009). The efficacy of both chloroquine and sulfadoxine-pyrimethamine in Laos is unsatisfactory.