Mefloquine prophylaxis: an overview of spontaneous reports of severe psychiatric reactions and convulsions.

Since the time of its introduction in 1985, mefloquine (Lariam) has been used extensively for malaria prophylaxis. The international Drug Safety Department of the manufacturer gathered all spontaneous adverse drug reactions reported in association with this drug from all available sources and monitored the literature on a world-wide basis. The serious neurologic and psychiatric adverse events reported in association with Lariam prophylaxis from the time of introduction until May 1991 were reviewed. During this time, 59 serious neurologic and psychiatric adverse reactions were reported as follows: 26 convulsions, 12 depressions, 20 psychotic episodes, and one toxic encephalopathy; none were fatal. While spontaneous reporting systems are biased by under-reporting, they provide useful instruments for analysis of clinical risks factors. The neurologic and psychiatric adverse events reported in association with mefloquine prophylaxis were of the same types as those reported with other quinine derivative antimalarials. The precise mechanism of serious neurologic and psychiatric reactions is unknown. The only patient population identified at this time as having an increased risk of developing these serious reactions to mefloquine are persons with a history of seizures or manic-depressive illness. Mefloquine prophylaxis should not be prescribed to such patients.