The haemolytic effect of various regimens of primaquine with chloroquine in American Negroes with G6PD deficiency and the lack of an effect of various antimalarial suppressive agents on erythrocyte metabolism.

In view of the fact that increased resistance to drugs by malaria parasites in some parts of the world may lead to increasing use of a combination of primaquine with chloroquine for chemotherapy, studies were made on the severity of the haemolytic anaemia induced by 45 mg primaquine in American Negroes with glucose-6-phosphate dehydrogenase deficiency. It was found that twice-weekly administration of primaquine induced more haemolysis than once-weekly administration, and that administration once weekly for 4 weeks and twice weekly thereafter resulted in a degree of anaemia falling between those produced by the other regimens. Anaemia was not induced in controls with no G6PD deficiency. One volunteer developed an intercurrent infection that was treated with salicylates; his haemolysis was markedly intensified, but whether by the infection, the salicylates or both could not be determined.In a conjoint study, the administration of six malaria-suppressive drugs had no detectable effect on the activities of several erythrocyte enzymes or on the levels of adenosine monophosphate, diphosphate or triphosphate.