Higher-Dose Primaquine to Prevent Relapse of Malaria.

Background: In most of the Americas, the recommended treatment to prevent relapse of malaria is primaquine at a total dose of 3.5 mg per kilogram of body weight, despite evidence of only moderate efficacy.

Methods: In this trial conducted in Brazil, we evaluated three primaquine regimens to prevent relapse of malaria in children at least 5 years of age and in adults with microscopy-confirmed monoinfection.