Can i use polymyxin b sulfate and trimethoprim ophthalmic for an ear infection?

Yes: A sterile eye antibiotic solution can be used in the ear, but not vice versa, since ear solutions aren't sterile.Dosage as follows: Inner ear infections, it is 1 drop every four hours,Outer ear infections, 4 drops every 6 hours.

Inner vs Outer: If this an inner ear infection then the antibiotic ointment will not be helpful. I recommend making an appointment with your PCP or an ENT to see if you have an infection. If you have already been diagnosed with 'otitis media' commonly referred to as an inner ear infection then the ointment will not help. Good luck to you