Randomized, parallel placebo-controlled trial of primaquine for malaria prophylaxis in Papua, Indonesia

Malaria causes illness or death in unprotected travelers. Primaquine preven ts malaria by attacking liver-stage parasites, a property distinguishing it from most chemoprophylactics and obviating 4-week postexposure dosing. A d aily adult regimen of 30 mg primaquine prevented malaria caused by Plasmodi um falciparum and P. vivax for 20 weeks in 95 of 97 glucose-6-phosphate deh ydrogenase (G6PD)-normal Javanese transmigrants in Papua, Indonesia. In com parison, 37 of 149 subjects taking placebo in a parallel trial became paras itemic. The protective efficacy of primaquine against malaria was 93% (95% confidence interval [CI] 71%-98%); against P. falciparum it was 88% (95% CI 48%-97%), and >92% for P. vivax (95% CI > 37%-99%). Primaquine was as well tolerated as placebo. Mild methemoglobinemia (mean of 3.4%) returned to no rmal within 2 weeks. Blood chemistry and hematological parameters revealed no evidence of toxicity. Good safety, tolerance, and efficacy, along with k ey advantages in dosing requirements, make primaquine an excellent drug for preventing malaria in nonpregnant, G6PD-normal travelers.