Because of the danger of a potentially fatal prolongation of the QTc interval, halofantrine must not be given simultaneously with or subsequent to mefloquine. Patients with a past history of psychiatric disturbances or convulsions should not be prescribed mefloquine prophylactically. In patients with epilepsy, mefloquine, especially when used in high doses, may increase the risk of convulsions. Therefore, in such patients, mefloquine should be used only for curative treatment and only if there are compelling medical reasons. Therefore, mefloquine is not recommended for use in patients with severe renal, hepatic or cardiac disease.
Mefloquine crosses the placenta.
There are no adequate and well-controlled studies in pregnant women. Mefloquine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Women of childbearing potential who are travelling to areas where malaria is endemic should be warned against becoming pregnant and advised to practice contraception during malaria prophylaxis with mefloquine. Caution should be exercised with regard to driving, piloting airplanes and operating machines, as dizziness, a disturbed sense of balance or neuropsychiatric reactions have been reported during the use of mefloquine. During prophylactic use, if signs of unexplained anxiety, depression, restlessness or confusion are noticed, these may be considered prodromal to a more serious event.