Introduction: Primaquine can produce adverse reactions as toxicity to blood when used in the treatment of vivax malaria. This work aimed to determine methemoglobinemia in patients with vivax malaria receiving oral therapy with primaquine.
Methods: Spectrophotometric quantification of methemoglobinemia and qualitative assay for glucose-6-phosphate dehydrogenase.
Results: Methemoglobinemia ranged from 2.85 to 5.45% in male patients and 3.77 to 7.34% in female patients.
Conclusions: A statistically significant increase in methemoglobinemia was observed following oral therapy with primaquine, with no clinical manifestations, and independent of sex and the qualitative expression of glucose-6-phosphate dehydrogenase.