Sulfonamide-derived drugs (non-antibacterial)

Name: Sulfonamide-derived drugs (non-antibacterial)
Creator: Jason Cafer, MD

Carry a sulfonamide group but — darunavir excepted — lack the N4 arylamine and N1 ring of the sulfa antibiotics
Every drug here has a label that contraindicates or warns on sulfonamide hypersensitivity
Structural cross-reactivity is weak: sulfa-allergic patients react to these at 9.9% vs 1.6% — but to penicillin even more often (Strom, NEJM 2003)
Thiazide-type and loop diuretics (except torsemide), carbonic anhydrase inhibitors, celecoxib, zonisamide, glimepiride, darunavir, simeprevir, tamsulosin, almotriptan
Labels are inconsistent: glimepiride contraindicated, glipizide and glyburide silent; almotriptan warns, sumatriptan does not
Ethacrynic acid is the loop diuretic without a sulfonamide; topiramate is a sulfamate, not a sulfonamide

Class at a glance

Carry a sulfonamide group but — darunavir excepted — lack the N4 arylamine and N1 ring of the sulfa antibiotics

Every drug here has a label that contraindicates or warns on sulfonamide hypersensitivity
Labels are inconsistent: glimepiride contraindicated, glipizide and glyburide silent; almotriptan warns, sumatriptan does not

Structural cross-reactivity is weak: sulfa-allergic patients react to these at 9.9% vs 1.6% — but to penicillin even more often (Strom, NEJM 2003)

Ethacrynic acid is the loop diuretic without a sulfonamide; topiramate is a sulfamate, not a sulfonamide

What structural features separate sulfa antibiotics from these drugs?
The N4 arylamine (the hapten) and the N1 heterocyclic ring — absent from every drug on this page.
Which loop diuretic can a sulfa-allergic patient take?
Ethacrynic acid — the only loop diuretic without a sulfonamide group.