Objectives: To compare the adverse effects of two regimens of chlorpheniramine plus chloroquine (CP+CQ) in childrenwho live in a countrywhere chloroquine resistantmalaria is endemic. Methods: 99 children with acute uncomplicated malaria were randomised into two treatment groups. Group I received high dose chlorpheniramine (6mg +12mg/day for 7days in children = 5years; 8mg + 18mg/day for 7days in those >5years) plus chloroquine 10mg/kg daily for 3 days. Group II received a 50% higher dose of chlorpheniramine plus chloroquine 10mg/kg daily for 3 days. Outcome measures were vital signs, clinical response and parasite clearance on days 0-7 and day 14. Results: Parasite clearance, fever clearance and cure rate were comparable for the two groups. Drowsiness occurred in 66.7% of high dose and 86.3% of higher dose CP+CQ subjects (p = 0.05). Compared to children treated with high dose, those treated with higher dose CP+CQhad significantly lower respiratory rates on day 2 (p = 0.001), day 6 (p = 0.015), and on day 14 (p = 0.003). Conclusion: The higher rates of drowsiness and lower respiratory rates in children treated with higher dose CP+CQ calls for caution in the clinical application of the higher dose combination. The higher dose has no additional benefit andmay in fact be dangerous.Keywords: Chloroquine resistant malaria, chlorpheniramine-chloroquine, treatment, adverse effects, drowsiness, respiratory depressio
