Primaquine Dosing in G6PD Deficiency

Primaquine Dosing Based on G6PD Status

For patients with G6PD deficiency, the recommended primaquine dosing for radical cure of P. vivax malaria is 0.75 mg/kg weekly (maximum 45 mg) for 8 weeks with close monitoring for hemolysis, specifically for those with intermediate G6PD deficiency (30-70% activity) and non-Mediterranean variant (A-) 1, 2
Quantitative G6PD testing should be performed before administering primaquine to any patient 1, 3
Primaquine should not be used in patients with severe G6PD deficiency (<30% activity) or Mediterranean variant (B-) due to very high risk of severe hemolysis 1, 2
Do not use primaquine if G6PD activity is <70% according to some guidelines 3

For intermediate G6PD deficiency (30-70% activity) with non-Mediterranean variant (A-), weekly primaquine at 0.75 mg/kg (maximum 45 mg) for 8 weeks is recommended, with close monitoring for hemolysis 1, 2
For normal G6PD activity, standard dosing is 30 mg base per day for 14 days 1, 3

The African variant (A-) has mild deficiency and is relatively resistant to severe primaquine-induced hemolysis 1, 2
The Mediterranean variant (B-) has very high risk of severe hemolysis even with extended dosing regimens 1, 2
Primaquine is contraindicated in pregnant or breastfeeding women 1, 3
Primaquine is contraindicated in patients with severe G6PD deficiency 1, 2

Ascorbic acid (Vitamin C) is the treatment of choice for methemoglobinemia in G6PD deficiency 4, 5
Avoid methylene blue in G6PD deficiency as it may worsen hemolysis 4, 5