Evaluation of the paediatric dose of chloroquine in the treatment of Plasmodium vivax malaria

This study is a secondary analysis of the data from a clinical trial in which children over 5 years of age were administered 25 mg/kg of CQ, and CQ concentrations in blood were measured at day 7 of follow-up. Models of regression and comparison were used to evaluate and compare the CQ dose taken per kg/body weight, the CQ dose calculated based on body surface area, CQ levels in blood on day 7 and the age of the population.

The younger the study population the greater the difference between the dose per kg/body weight (real dose) and that calculated according to the BSA (theoretical dose). The difference between the two doses was −181.206 mg in the 5–9 years of age group (CI 95 % −195.39; −167.02 mg) and −71.39 mg (CI 95 % −118.61; −23.99 mg) in the 10–14-year-old group. The CQ concentrations in blood on day 7 differed in patients over and under 15 years (p = 0.008). A negative correlation was found between the real and theoretical dose (difference in dose) and the age in years (R2 = 0.529, p = 0.001). A negative correlation was also found between the difference in dose (mg) and CQ concentrations on day 7 (ng/ml) (r = −0.337, p = 0.001). Children under 15 years were found to have a higher rate of therapeutic failure than those over 15 (28 vs 4.2 %, respectively) (Kaplan–Meier p = 0.005).