It is also quite effective against common bone and joint infections. Cephalexin is especially useful for staphylococcal or deep skin infections. Consequently, what antibiotic is used to treat ear infections in dogs? The antibiotics, like mometamax or Tresaderm, are used to fight the bacterial growth in the infection. Some common topical antibiotics prescribed for ear infections are Mometamax, Otomax, and Tresaderm, while commonly prescribed oral antibiotics include Amoxicillin, Clindamycin ...