Malaria with other antimalarials (known as artemisinin-combination therapy, or ACT), which decreases resistance to any single drug component. These additional antimalarials include: amodiaquine, lumefantrine, mefloquine or sulfadoxine/pyrimethamine. Another recommended combination is dihydroartemisinin and piperaquine. ACT is about 90% effective when used to treat uncomplicated malaria. To treat malaria during pregnancy, the WHO recommends the use of quinine plus clindamycin early in the pregnancy (1st trimester), and ACT in later stages (2nd and 3rd trimesters). In the 2000s (decade), malaria with partial resistance to artemisins emerged in Southeast Asia. Infection with "P. vivax", "P. ovale" or "P. malariae" usually do not require
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