Cetirizine is NOT Contraindicated in G6PD Deficiency
Cetirizine can be safely used in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency, as it is not among the medications with evidence of causing hemolysis in these patients.
Definitively Contraindicated Medications in G6PD Deficiency
Based on comprehensive evidence-based reviews, only seven medications are definitively contraindicated in G6PD deficiency 1:
- Dapsone - potent oxidant causing methemoglobinemia and hemolysis 2, 1
- Methylthioninium chloride (methylene blue) - causes severe hemolytic anemia 2, 1
- Nitrofurantoin 1
- Phenazopyridine 1
- Primaquine 2, 1
- Rasburicase - explicitly contraindicated per tumor lysis syndrome guidelines 3, 1
- Tolonium chloride (toluidine blue) 1
Why Cetirizine Is Safe
- No evidence exists in the medical literature linking cetirizine (an H1-antihistamine) to hemolysis in G6PD-deficient patients 1
- Real-world data from over 31,962 G6PD-deficient patients showed that the vast majority of hemolytic episodes (71.8%) were caused by fava bean ingestion, with only 3 cases (4.2%) potentially medication-related—none involving antihistamines 4
- Comprehensive medication safety reviews spanning decades of literature found no evidence to contravene the use of cetirizine or other antihistamines in normal therapeutic doses for G6PD-deficient patients 1
Clinical Context: What Actually Causes Hemolysis
The primary triggers for hemolysis in G6PD deficiency are 4, 5:
- Fava bean ingestion (most common cause - 71.8% of cases)
- Infections (8.5% of cases)
- The seven contraindicated oxidant medications listed above
- Severe oxidative stress from metabolic conditions
Common Pitfall to Avoid
Many medications have been wrongly cited as causing hemolysis because they were administered during infection-related hemolytic episodes, leading to decades of confusion and unnecessary medication restrictions 1. Cetirizine falls into this category of medications that have been inappropriately restricted without evidence.
Practical Recommendation
- Prescribe cetirizine at standard therapeutic doses for G6PD-deficient patients without hesitation 1
- Focus avoidance efforts on the seven definitively contraindicated medications listed above 2, 1
- Screen for G6PD deficiency before prescribing any of the seven high-risk oxidant drugs, particularly in patients of Mediterranean, African, Indian, or Southeast Asian descent 2