Gentamicin - Otic

By Rania Gollakner, BS, DVM, MPH

What is gentamicin?

Gentamicin (brand names: Gentocin®, Genoptic®, Gentak®) is an aminoglycoside antibiotic used to treat certain bacterial ear infections.

Its use in cats and dogs to treat bacterial infections in the ears is sometimes ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

How is gentamicin given?

Gentamicin can be found in many forms, but for otic use, it is an ointment, suspension, or ophthalmic solution that is used off label to treat ear infections. These medications are applied directly to the ear canal.

When using this medication with acidifying ear cleaners and/or aminoglycoside or fluoroquinolone-containing agents, this product should be administered an hour apart from these other treatments.

In veterinary-labeled products for otic use, gentamicin is only found in combination with other drugs, such as steroids and antifungals. Examples of these products include Mometamax®, Otomax®, Gentamicin Gentizol®, Vetromax®, MalOtic®, Otibiotic®, or Tri-Otic®.

What if I miss giving my pet the medication or my shipment is late?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Side effects of gentamicin include redness or increased inflammation. If this occurs, discontinue the medication and contact your veterinarian.

Are there any risk factors for this medication?

Gentamicin should not be used in patients with a history of hypersensitivity or allergy to it.

Are there any drug interactions I should be aware of?

Drug interactions have not been noted with topical use of gentamicin at this time.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working. Your pet should be rechecked before treatment is discontinued.

How do I store gentamicin?

Gentamicin should be stored in the refrigerator or at controlled room temperature away from moisture and sunlight; do not freeze.

Do not use if the color changes, it becomes cloudy, or if particles are seen in the solution.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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