Primaquine

Primaquine is a medication used to treat and prevent malaria and to treat Pneumocystis pneumonia. Specifically it is used for malaria due to Plasmodium vivax and Plasmodium ovale along with other medications and for prevention if other options cannot be used. It is an alternative treatment for Pneumocystis pneumonia together with clindamycin. It is taken by mouth. Primaquine is a medication used to treat and prevent malaria and to treat Pneumocystis pneumonia. Specifically it is used for malaria due to Plasmodium vivax and Plasmodium ovale along with other medications and for prevention if other options cannot be used. It is an alternative treatment for Pneumocystis pneumonia together with clindamycin. It is taken by mouth. Common side effects include nausea, vomiting, and stomach cramps. Primaquine should not be given to people with glucose-6-phosphate dehydrogenase (G6PD) deficiency due to the risk of red blood cell breakdown. It is often recommended that primaquine not be used during pregnancy. It may be okay in breastfeeding when the baby is known not to have G6PD deficiency. The mechanisms of action is not entirely clear but is believed to involve effects on the malaria parasites' DNA. Primaquine was first made in 1946. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. It is available as a generic medication. The wholesale cost in the developing world is US$0.04–0.11 per day. In the United States a typical course of treatment is $50–100. Primaquine is primarily used to prevent relapse of malaria due to Plasmodium vivax and Plasmodium ovale. It eliminates hypnozoites, the dormant liver form of the parasite, after the organisms have been cleared from the bloodstream. If primaquine is not administered to patients with proven P. vivax or P. ovale infection, a very high likelihood of relapse exists for weeks or months (sometimes years). Use in combination with quinine or chloroquine each of which is very effective at clearing P. vivax from blood, improves outcomes; they appear to also potentiate the action of primaquine. As of 2016, the Centers for Disease Control and Prevention recommended the use of primaquine for primary prophylaxis prior to travel to areas with a high incidence of P. vivax, and for terminal prophylaxis (anti-relapse therapy) after travel. A single dose of primaquine has rapid and potent ability to kill gametocytes (stage V) of P. falciparum and P. vivax in blood; it also kills asexual trophozoites of P. vivax in blood, but not of P. falciparum. Because of its action against gametocytes, the WHO recommends it for use in reducing transmission to control P. falciparum infections. Primaquine is also used in the treatment of Pneumocystis pneumonia (PCP), a fungal infection commonly occurring in people with AIDS and, more rarely, in those taking immunosuppressive drugs. To treat PCP effectively, it is usually combined with clindamycin. Primaquine has not been studied extensively in people 65 and older so it is not known if dosing should be adjusted for this population. Primaquine should not be administered to anyone with G6PD deficiency because a severe reaction can occur, resulting in hemolytic anemia. However, the WHO has recommended that a single dose of primaquine (0.25 mg/kg) is safe to give even in individuals with G6PD deficiency, for the purpose of preventing transmission of P. falciparum malaria.