Neomycin and polymyxin B are bacteria-fighting antibiotics often combined with the steroid hydrocortisone to treat outer ear bacterial infections, according to Drugs.com. However, the medicine does not treat inner ear infections, ruptured eardrums, or infected ears due to chickenpox or herpes.
The neomycin sulfate-polymyxin B sulfate combination effectively fights microorganisms that include Escherichia coli, Staphylococcus aureus and Haemophilus influenzae. The drugs are not effective against germs such as Streptococcus pneumoniae, notes Drugs.com. The drug combination has an acidic quality that can produce side effects such as stinging and burning. Some patients using neomycin experience minor skin reddening with dry scaling, swelling and itching.