Doses of primaquine administered to children with according to an age-based dose regimen.

Primaquine is still the first-line drug to eliminate hypnozoites of . The therapeutic efficacy is related to the total dose administered. In several endemic areas, the drug is administered for children in an age-based regimen, which can lead to inadequate exposure, increasing the rates of recurrence of the infection. The present study aims to describe the mg/kg total dose of primaquine administered to children for treatment for vivax malaria when an age-based regimen is used and to measure the plasma concentrations of primaquine and carboxyprimaquine. A total of 85 children were included in the study. The total dose of primaquine administered based on mg/kg had a median value of 3.22 mg/kg. The percentage of patients with a total dose below the required dose of 3.5 mg/kg was 55.75%. The median primaquine maximum concentration was 94 ng/ml. For carboxy-primaquine, the median maximum concentration was 375 ng/ml. The results suggest that age-based dosing regimens likely lead to substantial under-dosing of primaquine, which is evident in the youngest children and is reflected in decreased levels of primaquine and carboxy-primaquine in plasma samples 13.