Neuropsychiatric events during prophylactic use of mefloquine before travelling

It has been suggested that neuropsychiatric events during use of mefloquine are more common in females than in males and are partly explained by the psychological stress of travelling. Therefore, we investigated neuropsychiatric events in females and males on mefloquine in the 3-week prophylactic period that precedes travelling. Furthermore, we investigated whether first-time users had a higher risk of neuropsychiatric adverse events than subjects with a history of mefloquine use.

We enrolled all patients who visited a Travel Clinic for mefloquine prophylaxis during the period 1 May 1999 to 7 March 2000. Each patient was followed from baseline (prior to starting mefloquine) up to 3 weeks after the start of mefloquine but before travelling. We asked patients to register any adverse event in a diary and measured the intra-individual change in scores on the Dutch Shortened Profile Of Mood States (POMS) at baseline and at the end of follow-up.

The final cohort consisted of 179 subjects with a mean age of 3 years. Females reported adverse events more frequently than males ( P=0.005). Overall, we observed a small but significant increase in the score on the domain fatigue [0.74 points, 95% confidence interval (CI) 0.18, 1.30]. The effect was exclusively present in females and not in males. First-time users of mefloquine increased 2.81 points (95% CI 0.70, 4.92) on the total score of the POMS, and among those, women showed the largest increase of 4.58 points (95% CI 0.74, 8.43).

The use of mefloquine was associated with neuropsychiatric adverse effects. Females encountered neuropsychiatric effects more frequently than males, which could be confirmed by validated psychological tests. Neuropsychiatric effects were more common in first-time users than in individuals who had used mefloquine before.