Question: is neomycin a sulfa drug?
Answer: For instance, common ophthalmic medications such as atropine sulfate, polymyxin B sulfate/trimethoprim (Polytrim®), gentamicin sulfate, and neomycin sulfate are by definition not considered sulfonamides, as they lack the characteristic SO2NH moiety linked directly to a benzene ring that defines such a group [9].