[Adverse effects associated with antimalarial chemoprophylaxis]

To evaluate the frequency and type of adverse drug reactions associated to the antimalarial chemoprophylaxis advised to travellers visiting endemic areas.

We included the travellers who from july 1992 to june 1994 came to the Travellers Advise Department and made short-term travels to areas with malarial infection risk. The adverse drug reactions were reported by the travellers through a questionnaire handed at the consulting room. The pharmacological regimens advised were: a) chloroquine base 5 mg/kg/week. b) chloroquine base 5 mg/kg/week + proguanil 100 mg/day if weight less than 55 kg and 200 mg/day if weight more than 55 kg. c) mefloquine 250 mg/week.

We evaluated 1,054 questionnaires for the study. The 18.4% of the travellers reported adverse drug reactions. The 12.4% of the travellers who were on chloroquine, the 17.2% of those who were on chloroquine + proguanil and the 20.3% from mefloquine group presented adverse drug reactions (differences without significance). Comparing the regimens studied, we observed that neuropsychiatric reactions were more frequent in the mefloquine group (p < 0.01), the gastrointestinal reactions were less common in the chloroquine group (p = 0.04) and the transitory eye disorders were more frequent in the chloroquine + proguanil group (p = 0.01). In the mefloquine group the travellers with adverse drug reactions had a significantly lower weight than those who did not present them (p < 0.01).

The adverse drug reactions reported agree with the toxicologic profile described in the literature about these drugs. Mefloquine presents an outstanding neuropsychiatric toxicity and is worse tolerated in low weight patients.