Should people with allergies avoid hydrochlorothiazide (HCTZ)?

Manufacturers say hydrochlorothiazide (HCTZ) is contraindicated for people who are hypersensitive to HCTZ or to other sulfonamide-derived drugs.¹  No other HCTZ contraindications due to allergies are noted in the prescribing information.

A 2013 review of 45 years of medical literature only found 17 research articles on the potential for people with a sulfonamide antibiotic allergy being cross-reactive to non-antibiotic sulfonamide-based medications (such as HCTZ).² Only a few case reports of possible HCTZ cross-reactivity were found and in all cases testing and follow-up were not done to verify that the reported symptoms were due to HCTZ. Wulf NR and Matuszewski KA concluded that nonantibacterial sulfonamide agents should not be withheld from people who had prior reactions to an antibacterial sulfonamide. However, prescribing information leans on the side of caution and lists any previous sulfonamide allergic reaction as a contraindication for HCTZ.¹

 ^References

1. Hydrochlorothiazide [package insert]. Morgantown, WV: Mylan Pharmaceuticals, Inc.; 2011.
2. Wulf NR, Matuszewski KA. Sulfonamide cross-reactivity: is there evidence to support broad cross-allergenicity? Am J Health Syst Pharm 2013; 70 (17): 1483-1494.