What is the only FDA approved form of Bacitracin?

• A. Oral
• B. Topical
• C. IV
• D. IM

Answer: (B)

Bacitracin is kept to topical use because systemic administration carries significant toxicity risks, especially nephrotoxicity. It works by inhibiting the dephosphorylation of bactoprenol, a carrier needed to move peptidoglycan precursors across the bacterial membrane, which makes it effective mainly against Gram-positive bacteria when used locally. Because of the safety concerns with systemic exposure, the FDA has approved formulations for topical use only. So, the form that meets FDA approval is the topical preparation, such as the ointment used on the skin (and ophthalmic topical applications as another local route).