Types of Antibiotics for Dog Ear Infections

By Betty Lewis

Ear infections are fairly routine among dogs and usually are caused by yeast or bacteria. Treating the infection depends on properly diagnosing the cause, and usually the vet will collect debris from inside the dog's ear to determine precisely what type of infection is at play. Prescription antibiotics, often in topical form, will target and treat the infection.

Developing an Ear Infection

If your dog's shaking his head a lot and scratching his ears, he may be responding to an ear infection. Yeast and bacteria can cause this type of discomfort, as well as redness and discharge leaking from his ears. Generally, a bacterial infection in a dog's ear is a secondary occurrence, developing in response to inflammation and an unhealthy environment in his ear. A variety of factors can contribute to ear infections, including:

  • Mites
  • Allergies
  • Foreign material in the ear
  • Systemic illness, such as hypothyroidism
  • Growths in the ear canal
  • Excessive moisture, hair or wax

Other illness or allergies are usually the primary cause of the problem. Additionally, ear infections that begin in the outer ear can progress into the middle or inner ear if left unchecked. Successful long-term treatment of an ear infection requires addressing the primary cause of the infection and any secondary responses.

Treating an Ear Infection

In most cases, the vet will clean the dog's ear before administering any medication so the ear doesn't provide an environment that fosters more bacterial or fungal growth. Treatment usually involves a liquid, ointment or cream antibiotic applied directly into the ear. Occasionally, the vet may administer an injection or prescribe oral antibiotics to provide a faster response to the infection. In the case of a yeast infection, antifungals are necessary and steroids also may be part of the treatment regimen to reduce inflammation and swelling.

Topical Antibiotics

There are a host of antibiotics to choose from when it comes to treating a dog's ear infection. The type of drug chosen depends on what type of infection the dog has. Many medications contain an antibiotic combined with a steroid and antifungal.

  • Otomax is a combination ointment, combining the antibiotic gentamicin with the antifungal clotrimazole and the steroid betamethasone.
  • Tresaderm is composed of the antifungal thiabendazole combined with neomycin as an antibiotic and the steroid dexamethasone, administered as drops.
  • Panalog is the combination of an antifungal known as nystatin, neomycin, the antibacterial thiostrepton and triamcinolone acetonide, a steroid. It's available as an ointment, cream or in tablet form.
  • Mometamax is an ointment containing gentamicin combined with clotrimazole and the steroid mometasone.

Some topical medications are simply antibiotics, such as Baytril otic, a liquid form of the broad spectrum antibiotic enrofloxacin.

Oral Antibiotics

Occasionally a dog requires additional antibiotics, particularly for more persistent, hardy forms of bacteria such as Pseudomonas aeruginosa. Oral antibiotics in the quinolone class, such as enroflaxin and orbiflaxcin are effective at taking on more resistant bacteria. Cephalexin can be useful for stubborn ear infections. Though not an antibiotic, oral ketoconazole is an antifungal sometimes used to treat yeast infections.

Side Effects

Depending on the medication, a dog may experience irritation, swelling or redness in his ear as a side effect. Some dogs develop temporary deafness when taking Otomax. Your vet should ensure your dog's ear drum is intact before administering any topical ear medication. Administer all medication as directed by your vet, even if the ear looks healed.