I have a sulfa allergy. Do I need to avoid certain medications?

Answer From James T C Li, M.D., Ph.D.

Someone who has a sulfa allergy can react to some medications that contain sulfa.

Sulfonamide antibiotics that can cause a reaction

Antibiotics containing chemicals called sulfonamides can trigger a reaction if you have a sulfa allergy. These antibiotics include combination drugs:

  • Sulfamethoxazole-trimethoprim (Septra, Bactrim)
  • Erythromycin-sulfisoxazole

Other medications that may cause a reaction

Other types of sulfa medications may trigger a reaction in some people who have a sulfonamide antibiotic allergy:

  • Sulfasalazine (Azulfidine), used to treat Crohn's disease, ulcerative colitis and rheumatoid arthritis
  • Dapsone, used to treat leprosy, dermatitis and certain types of pneumonia

Keep in mind that if you have a reaction to a sulfonamide antibiotic, you may still be able to take other sulfonamide medications without having a reaction.

Sulfonamide medications that may be OK

  • Certain diabetes medications — glyburide (Glynase, Diabeta) and glimepiride (Amaryl), for example
  • Some nonsteroidal anti-inflammatory drugs, such as celecoxib (Celebrex)
  • The migraine medication sumatriptan (Imitrex)
  • Certain "water pills" (diuretics), such as furosemide (Lasix) and hydrochlorothiazide (Microzide)

An allergy to sulfonamide medications is different from having an adverse reaction to wine or food that contains sulfites. Having a reaction to sulfites in something you eat or drink doesn't mean you'll be allergic to sulfonamide medication.

If you have HIV/AIDS, you may have an increased sensitivity to sulfonamide medications. Always tell your doctor about your sensitivities to medication.

There are no diagnostic tests for sulfa allergy. However, sulfa desensitization might be an option, especially if medication containing sulfamethoxazole is needed.

Oct. 06, 2023