Antibiotics and Other Sulfonamides to Avoid If You Have a Sulfa Allergy Sulfa drugs are synthetic (man-made) medications made from sulfanilamide that contain antibacterial properties. Sulfa drugs ...

The Canadian researchers found that the antibiotics that were most likely to ilicit this reaction were cephalosporins and sulfonamides - or 'sulfa drugs'. As well as penicillin, cephalosporins ...