Cetirizine Safety in G6PD Deficiency
Cetirizine is safe to use in patients with G6PD deficiency at standard therapeutic doses, as antihistamines are not among the medications that cause hemolysis in this population.
Evidence-Based Medication Classification
The most comprehensive and recent evidence establishes that only seven medications are definitively contraindicated in G6PD deficiency 1, 2, 3, 4:
- Dapsone 1, 2
- Methylthioninium chloride (methylene blue) 1, 2
- Primaquine 1, 2
- Rasburicase 1, 2
- Nitrofurantoin 3
- Phenazopyridine 3
- Tolonium chloride (toluidine blue) 3
Cetirizine does not appear on any contraindicated or cautionary medication lists for G6PD deficiency 1, 2, 3, 4.
Real-World Safety Data
A large-scale real-world study of 31,962 G6PD-deficient patients found that only 71 cases (0.2%) experienced major hemolysis requiring hospitalization over a 13-year period 5. Of these cases:
- 71.8% were caused by fava bean ingestion 5
- 8.5% were associated with infections 5
- Only 4.2% (3 cases) were potentially medication-related, involving nitrofurantoin, phenazopyridine, and an unspecified "pain killer" 5
This study demonstrated that hundreds to thousands of G6PD-deficient patients safely received medications previously suspected of causing hemolysis, providing reassurance that the actual risk from most medications is extremely low 5.
Clinical Implications for Antihistamine Use
Antihistamines like cetirizine have never been documented to cause hemolytic crises in G6PD-deficient patients 3, 4. The systematic literature review that established the seven definitively contraindicated medications found no evidence contraindicating antihistamine use in normal therapeutic doses 3.
Important Monitoring Considerations
While cetirizine is safe, when starting any new medication in G6PD-deficient patients, monitor for signs of hemolysis 1:
Common Pitfall to Avoid
Many medications have been wrongly cited as causing hemolysis because they were administered during infection-related hemolytic episodes, leading to confusion about which drugs are truly dangerous 3. The evidence shows that cetirizine and other antihistamines can be prescribed without concern for G6PD status 3, 4.