Reported side effects to chloroquine, chloroquine plus proguanil, and mefloquine as chemoprophylaxis against malaria in Danish travelers

Background:The aim of the study was to provide data on the relative frequen cy of reported symptoms in travelers using chloroquine, chloroquine plus pr oguanil, and mefloquine. Method:The study was an open, nonrandomized study recording self-reported e vents in travelers recruited consecutively from two travel clinics in Copen hagen, Denmark, The main outcome measures were the relative proportion of t ravelers reporting particular symptoms in the three prophylaxis groups, com pliance, hospitalization and premature termination of the travel. Results: From May 1996 to April 1998 5,446 travelers were included and 4,15 8 questionnaires (76.3%) returned. Compliance was significantly better in m efloquine users with 83.3% of short term travelers compared to 76.3% in chl oroquine plus proguanil users. Also, 84.8%, 59.3% and 69.5% using chloroqui ne, chloroquine plus proguanil, and mefloquine respectively reported no sym ptoms and 0.6%, 1.1% and 2.8% reported "unacceptable" symptoms. Compared to chloroquine, mefloquine users had a significantly higher risk of reporting depression, RR 5.06 (95% Cl 2.71 - 9.45), "strange thoughts" RR 6.36 (95% Cl 2.52 -16.05) and altered spatial perception, RR 3.00 (95% Cl 1.41 - 6.41 ). Conclusion: Overall mefloquine is tolerated at least as well as chloroquine plus proguanil and shows better compliance, however, symptoms related to t he central nervous system are more prevalent in mefloquine users and when s ymptoms develop, they are perceived as more severe.