Malaria in pregnant women and infants, and in preschool children where transmission is seasonal. There are a number of medications that can help prevent or interrupt malaria in travelers to places where infection is common. Many of these medications are also used in treatment. In places where "Plasmodium" is resistant to one or more medications, three medications—mefloquine, doxycycline , or the combination of atovaquone/proguanil ("Malarone")—are frequently used for prevention. Doxycycline and the atovaquone/proguanil are better tolerated while mefloquine is taken once a week. Areas of the world with chloroquine sensitive malaria are uncommon. The protective effect does not begin immediately, and
Mefloquine events, about 11-17% of travelers are incapacitated to some degree. Mefloquine may cause abnormalities with heart rhythms that are visible on electrocardiograms. Combining mefloquine with other drugs that cause similar effects, such as quinine or quinidine, can increase these effects. Combining mefloquine with halofantrine can cause significant increases in QTc intervals. Mefloquine is contraindicated in those with a previous history of seizures or a recent history of psychiatric disorders. Women should not become pregnant and should use effective birth control while taking mefloquine. A retrospective analysis of outcomes in more than 2,500 women found no evidence that mefloquine was associated