Review and drug therapy implications of glucose-6-phosphate dehydrogenase deficiency

The pathophysiology, diagnosis, and medication-use implications of glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzyme deficiency in humans, are reviewed.

Originally identified as favism in patients who experienced hemolysis after ingestion of fava beans, G6PD deficiency results from an X-linked chromosomal mutation that leads to reduced activity of the enzyme responsible for the final step of the pentose phosphate pathway, through which reduced nicotinamide adenine dinucleotide phosphate required for protection of cells from oxidative stress is produced. G6PD deficiency affects about 400 million people worldwide. Diagnosis of G6PD can be made through detection of enzymatic activity (by spectrophotometric testing, fluorescence testing, or formazan-based spot testing) or molecular analysis to detect known mutations of the gene encoding G6PD. Most individuals with G6PD deficiency are asymptomatic throughout life. Symptoms of acute hemolysis associated with G6PD deficiency include anemia, fatigue, back or abdominal pain, jaundice, and hemoglobinuria. The most common precipitators of oxidative stress and hemolysis in G6PD deficiency include medication use and infection.

G6PD deficiency should be considered in patients who experience acute hemolysis after exposure to known oxidative medications, infection, or ingestion of fava beans. A diagnosis of G6PD deficiency is most often made through enzymatic activity detection, but molecular analysis may be required in females heterozygous for the disorder. When clinically feasible, rasburicase, primaquine, dapsone, pegloticase, and methylene blue should not be used until a G6PD diagnostic test has been performed.