Other antimicrobial allergies


Patients who have an allergic reaction to a sulfonamide antibiotic should not be labelled as ‘allergic to sulfur’. 

There is no cross-reactivity between sulfonamide antibiotics and non-antibiotic sulfonamides (e.g. sulfonylurea anti-diabetic drugs or diuretics such as frusemide). The only exception is sulfasalazine (Salazopyrin, Pyralin) – avoid sulfonamide antibiotics in patients with a history of hypersensitivity to sulfasalazine, and vice versa.

Cross-reactivity between antibiotic sulfonamides is estimated to be approximately 10%.

Sulfonamide antibiotics

Generic name
Common brands
Resprim, Septrim, Septrim Forte, Bactrim DS (in combination with trimethoprim)
Flamazine (silver sulfadiazine cream) - No oral or IV formulations marketed in Australia
Bleph-10 eye drops

More information on sulfonamide allergies is available from Australian Society of Clinical Immunology and Allergy (ASCIA) website


Carbapenems available in Australia include meropenem, ertapenem, doripenem, and imipenem.

The beta-lactam core structure of carbapenems is significantly different to penicillins and the risk of cross-reactive allergy to carbapenems in those who are allergic to penicillins is negligible.

Due to their broad spectrum, carbapenems are usually administered in the hospital setting where a drug challenge can be considered if required.

^ Back to top