Mefloquine for preventing malaria in non-immune adult travellers.

Abstract

Mefloquine is a commonly prescribed antimalarial drug which has now largely replaced earlier malaria chemoprophylaxis, since increasing parasite resistance has meant that these earlier drugs are no longer considered to be effective against all Plasmodium species. However mefloquine may be associated with neuropsychiatric harmful effects. The objective of this review was to assess the effects of mefloquine in adult travellers. We searched the Cochrane Infectious Diseases Group trials register, MEDLINE, EMBASE, Lilacs, Science Citation Index and reference lists of articles. We contacted researchers in the subject of malaria chemoprophylaxis, and drug companies. Randomised trials comparing mefloquine with other standard prophylaxis or placebo in non-immune adult travellers, and in non-travelling volunteers. We compiled and included in the review a database of published case reports of mefloquine adverse effects. We independently assessed trial quality and extracted data. We also contacted study authors. We included 10 trials involving 2750 non-immune adult participants. Five of these were field trials, and of these all were in soldiers. One trial comparing mefloquine with placebo showed mefloquine prevented malaria episodes in an area of drug resistance (odds ratio 0.04, 95% confidence interval 0.02 to 0.08). Withdrawals in the mefloquine group were consistently higher in four placebo controlled trials (odds ratio 3.56, 95% confidence interval 1.67 to 7.60). In five trials comparing mefloquine with other chemoprophylaxis, no difference in tolerability was detected. We found 519 published case reports of mefloquine adverse effects. 71 per cent of these published reports involved tourists and business travellers. Mefloquine prevents malaria, but there is not enough evidence to evaluate its tolerability in non-military travellers. There is evidence from non-randomised studies that mefloquine is a potentially harmful drug for tourists and business travellers, needing more careful evaluation. A randomised tolerability study is urgently needed in these groups.