Primaquine Phosphate

Adults: The dose of primaquine depends on why it is being used and on the patient's glucose-6-phosphate dehydrogenase (G6PD) status. Terminal prophylaxis with primaquine is only for a selected group of travellers, for example those who have had prolonged exposure in malaria endemic areas. For the radical cure of vivax and ovale malaria, primaquine should be given after appropriate treatment with chloroquine. The usual adult dose to prevent relapse is 15 mg base daily for 14 days. A higher dose of 30 mg base daily for 14 days can be given for less sensitive strains of the parasite, as long as the patient's G6PD is normal, but this higher regimen should not be used routinely. A suggested dose for children is 200 to 300 mcg per kg body-weight daily for 14 days. In patients with G6PD deficiency, haemolysis caused by primaquine is less when the medicine is given at intervals instead of daily. So the preferred regimen is 45 mg base once weekly for 8 weeks, or 30 mg base once weekly for 15 weeks, depending on the type of G6PD deficiency. Strict medical supervision is essential. As a gametocytocide in P. falciparum, adults are given a single dose of 30 to 40 mg base. Because primaquine is relatively toxic, it should not be given to children under one year of age. Older children can receive it, but only under careful medical supervision.