Practical Issues in the Management of Hypersensitivity Reactions: Sulfonamides

Stephen A. Tilles, MD, Departments of Medicine and Pediatrics, Division of Allergy and Clinical Immunology, and the Allergy and Asthma Clinic, Oregon Health Sciences University, Portland

South Med J. 2001;94(8) 

In This Article

What Constitutes a Sulfonamide

A sulfonamide is a chemical entity characterized by a sulfur dioxide (SO2) and nitrogen (N) moiety directly linked to a benzene ring (Fig 1). Many medication classes contain this chemical entity, including sulfonamide antimicrobials (eg, sulfamethoxazole, sulfadiazine, sulfacetamide), carbonic anhydrase inhibitors (eg, acetazolamide, methazolamide), sulfonylureas (eg, glyburide, glipizide), diuretics (eg, hydrochlorothiazide, chlorthalidone, furosemide, bumetanide), uricosurics (eg, probenecid), drugs for inflammatory bowel disease (eg, sulfasalazine), selective serotonin-1 receptor agonists (eg, sumatriptan), and the specific cyclooxygenase-2 inhibitor celecoxib.[5,6,7] Several structural differences exist among these medication classes. A major difference between sulfonamide antimicrobials and other sulfonamide-containing medications is the presence of an arylamine group (NH2) at the N4 position. It has been hypothesized that the arylamine group is critical in producing hypersensitivity reactions.[8] Only sulfonamide antimicrobials contain this group. Other differences are apparent in the substitutions attached to the sulfonamido group at the N1 position of the benzene ring (Fig 2).[8,9]

Structures of sulfonamide-containing medications.

Structural sites important to sulfonamide-induced hypersensitivity reactions and cross-allergenicity.[8,9]


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