People who have had an allergic reaction to hydrochlorothiazide (HCTZ) or a sulfonamide drug in the past, should not take HCTZ. HCTZ is safe for people with other types of allergies.
Sulfonamides are a group of antibiotics with similar chemical make-ups. They usually start with the letters “sulf” such as sulfamethoxazole which is found in the antibiotic medicine Bactrim.
Tell your doctor about all your allergies, especially to any medicines. This helps your doctor make better decisions about medicines for you.