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Medications to Avoid with a Sulfa Allergy


Updated June 03, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What medications should sulfa-allergic patients avoid?

The following list is by no means comprehensive. People with allergy to sulfa or sulfonamide-related medications should always check with their doctor or pharmacist prior to starting any new medications.

Sulfa antibiotics. In people with adverse reactions to sulfonamide antibiotics, all other sulfonamide antibiotics should be avoided. These include trimethoprim-sulfamethoxazole (Septra®, Bactrim® and generics), sulfadizine, sulfisoxazole, and dapsone. Topical sulfa antibiotics, such as sulfacetamide eye drops/shampoos/creams, silver sulfadiazine cream, and sulfanilamide vaginal preparations.

Diuretics (water pills). The risk for sulfa-containing diuretic medications causing reactions in sulfa-allergic patients is low. Many diuretic medications, such as hydrochlorothiazide (HCTZ) and furosemide (Lasix) are sulfa-based, while ethacrynic acid (Edecrin) is not. While there is no proof that people with an allergy to sulfa-based antibiotics will also react to sulfa-based non-antibiotics, it is recommended that a sulfa-allergic person take the first dose of a sulfa-based diuretic under direct medical supervision.

Sulfonylureas. Oral medications used for the treatment of diabetes, called sulfonylureas (such as chloropropamide, glyburide, and glipizide), are structurally similar to sulfonamides. While there are a few reports of these medications causing problems in sulfa-allergic patients, these medications are generally tolerated.

Celebrex®. Celecoxib (Celebrex®), a popular COX-2 inhibitor used for the treatment of arthritis and pain control, is a sulfonamide non-antibiotic medication. Although there have been no reports of sulfa-allergic patients reacting to Celebrex®, it is a theoretical concern, so the recommendation is that sulfa-allergic patients avoid this medication.

Sulfasalasine. Sulfasalasine is a sulfonamide that is related to aspirin, and is used for inflammatory bowel disease and rheumatoid arthritis. This medication should not be used in people with sulfa allergy.

Imitrex®. Sumatriptan (Imitrex®), used for the treatment of migraine headaches, is related structurally to sulfonamides, although there is no evidence that people with sulfa allergy are at increased risk for reactions from this medication.

Zonisamide. Zonisamide is a sulfonamide medication used for the treatment of seizures. It has been associated with severe skin reactions, those typically seen with sulfa reactions. This medication should not be used in sulfa-allergic patients.

Sulfa reactions never happen at a good time -- and sometimes happen at the worst time, such as on your wedding day, vacation or other special event. Did sulfa allergy ruin your special day? Share your story on how sulfa allergy ruined your special event.


    1. Strom BL, Schinnar R, Apter AJ, et al. Absence of Cross-Reactivity between Sulfonamide Antibiotics and Sulfonamide Nonantibiotics. N Engl J Med 2003;349:1628-35.
    2. Choquet-Kastylevsky G, et al. Allergic Adverse Reactions to Sulfonamides. Current Allergy and Asthma Reports. 2002;2:16-25.
    3. Allen J. Which Medications to Avoid in Patients with Sulfa Allergy? Prescriber's Letter. July 2000.

DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.

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