Mayo Clinic Health Library


Sulfa allergy: Which medications should I avoid?

I have a sulfa allergy. How can I tell if a medicine contains sulfa?

Updated: 03-11-2011


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

  • Trimethoprim-sulfamethoxazole (Septra, Bactrim)
  • Erythromycin-sulfisoxazole

Other types of sulfa medications may trigger a reaction in some people who have a sulfa allergy. Examples include:

  • 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, if you have a reaction to a sulfonamide antibiotic, you may still be able to take other sulfonamide medications without having a reaction. Examples of sulfonamide medications that may be OK include:

  • 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, Sumavel Dosepro)
  • Certain "water pills" (diuretics), such as furosemide (Lasix) and chlorothiazide (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.