Two common topical antibiotics that are available over-the-counter include Neosporin and bacitracin zinc. Both medications are for minor skin infections, according to WebMD. Consumers should use neither over large areas of the skin or for longer than a week, without a doctor's recommendation.
Neosporin contains bacitracin zinc as one of its active ingredients, notes WebMD. Its other active ingredients are neomycin and polymyxin, which are also antibiotics. It only treats bacterial skin infections and is ineffective for fungal or viral infections. Like prescription antibiotics, over-the-counter Neosporin can become less effective with overuse of the product. Using the medication requires applying a light coat over the injury. Thicker applications of the product do not increase its effectiveness.