infectious diseases
Malaria
Prevention of Relapses ofP. vivaxorP. ovaleMalaria
Hypnozoites must be eliminated from the liver withprimaquineortafenoquineto prevent relapses ofP. vivaxorP. ovale.Primaquineortafenoquinemay be given simultaneously withchloroquineor afterward. SomeP. vivaxstrains are less sensitive, and relapse may occur, requiring repeated treatment.Primaquineis not necessary forP. falciparumorP. malariaebecause these species do not have a persistent hepatic phase. If exposure toP. vivaxorP. ovaleis intense or prolonged or if travelers are asplenic, a 14-day prophylactic course ofprimaquineor a single dose oftafenoquinestarting when travelers return reduces the risk of recurrence. The main adverse effect is hemolysis in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD levels should be determined beforeprimaquineortafenoquineis given. Primaquineis contraindicated during pregnancy and breastfeeding, unless the infant has been shown not to be G6PD deficient. In pregnant women, chemoprophylaxis with weeklychloroquinecan be given for the remainder of pregnancy, and after delivery, women can be givenprimaquine, provided they are not G6PD deficient. 