Cetirizine is Safe in G6PD Deficiency
Cetirizine can be used safely in patients with G6PD deficiency without special precautions, as antihistamines are not associated with hemolytic risk in this population.
Evidence-Based Risk Classification
The most comprehensive and recent evidence systematically categorizes medications by hemolytic risk in G6PD deficiency. Only seven medications have solid evidence for causing hemolysis and should be absolutely avoided: dapsone, methylene blue, nitrofurantoin, phenazopyridine, primaquine, rasburicase, and tolonium chloride 1, 2. Cetirizine is not among these high-risk agents.
Real-World Safety Data
Large-scale real-world evidence from over 31,962 G6PD-deficient patients followed for 13 years demonstrated that:
- Only 71 cases (0.2%) experienced major hemolysis requiring hospitalization 3
- Of these, 71.8% were caused by fava beans, 8.5% by infections, and only 4.2% possibly by medications 3
- Hundreds to thousands of G6PD-deficient patients safely received various medications previously suspected as risky, with no documented hemolytic events 3
This data provides strong reassurance that medications not on the established high-risk list—including antihistamines like cetirizine—can be prescribed safely 3.
Mechanism and Pathophysiology
G6PD deficiency impairs the pentose phosphate pathway, reducing antioxidant protection against oxidative stress 4. Hemolysis occurs only with potent oxidant drugs that overwhelm the reduced reductive capacity of G6PD-deficient red blood cells 5. Cetirizine, as a second-generation antihistamine, lacks oxidative properties and does not generate the oxidative stress required to trigger hemolysis.
Clinical Implications
- No screening for G6PD deficiency is needed before prescribing cetirizine 6, 7
- Standard dosing applies without modification 1
- No special monitoring for hemolysis is required 2
Common Pitfall to Avoid
Many medications have been wrongly cited as causing hemolysis because they were administered during infection-related hemolytic episodes, leading to false attribution 1. The absence of cetirizine from all evidence-based contraindication lists, combined with its non-oxidative mechanism, confirms its safety profile 1, 2.