The impact of Malarone and primaquine on psychomotor performance

Recent evidence has established the effectiveness of Malarone and primaquine for chemoprophylaxis against Plasmodium falciparum malaria. Both have the advantage of providing causal prophylaxis and therefore require continued dosing for only 1 wk after departure from a malaria endemic area. Canadian Forces aircrews are often placed in situations that put them at risk for malaria infection but the safety of these drugs for use in aircrew has not been ascertained. This study was undertaken to determine whether or not Malarone or primaquine impact psychomotor performance.

Twenty-eight subjects (20 men and 8 women) ranging from 21 to 52 yr of age were assessed for psychomotor performance on 2 psychomotor test batteries at the end of a 7-d dosing protocol for each of placebo, Malarone, and primaquine treatment, in a double-blind crossover design with counterbalanced treatment order. All subjects were also assessed for psychomotor performance once per week during the 3-wk washout intervals. The daily Malarone dose was atovaquone 250 mg/proguanil 100 mg and the daily primaquine dose was 30 mg of base. In order to verify subject compliance with the medication dosing protocol, blood samples were drawn from all subjects at the end of each of the three 7-d loading protocols. All three medications were packaged in identical gelatin capsules for blinding purposes. At each psychomotor test session, all subjects completed a drug side-effect questionnaire, a mood questionnaire, and a sleepiness/fatigue questionnaire.

There was no significant impact of Malarone or primaquine on serial reaction time, logical reasoning, serial subtraction, or multitask performance. With respect to drug adverse effects there were no significant main effects or interactions for the documented adverse effects of these medications (abdominal cramps, epigastric distress, nausea, vomiting, anorexia, headache, coughing and dizziness).

There was no impact of either Malarone or primaquine on psychomotor performance, mood, sleepiness, or fatigue. The usual adverse effects of these medications were not significantly manifested in our subjects. These findings support the possible use of either Malarone or primaquine in aircrew for malaria chemoprophylaxis.