Osurnia® for Dogs

Molly Price, DVM
By Molly Price, DVM on Apr. 30, 2024
dog getting ear examined at vet clinic

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PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.

What Is Osurnia® for Dogs?

Osurnia® is an FDA-approved veterinary prescription ear gel that may be used in dogs for the treatment of otitis externa (outer ear infections).

The manufacturer recommends Osurnia® be administered in a veterinary clinic by a veterinary professional. It is considered a safe, effective, and convenient treatment by veterinarians for ear infections in dogs due to these unique features:

  • Only two treatments seven days apart.
  • The benefits of treatment last 45 days.

Osurnia® for dogs is a combination product containing an antibiotic (florfenicol), an antifungal (terbinafine), and a steroid anti-inflammatory (betamethasone acetate). Your veterinarian will perform a thorough exam of your dog’s ear and test the ear discharge to determine if Osurnia® is the best choice to treat your dog’s ear infection.

Osurnia® Considerations for Dogs

It’s important to have your dog’s ears examined by your veterinarian first before applying Osurnia®. Using Osurnia® in a dog with a damaged eardrum can cause toxicity and damage to the ear.

Osurnia® should not be used in dogs with known hypersensitivity to florfenicol, terbinafine, betamethasone acetate, or similar medications in the same drug classes.

Osurnia® should not be used in breeding, pregnant, or nursing dogs, as safety studies in these dogs had not yet been performed at the time of this publication. Osurnia® should be used with caution in dogs with recurring ear infections, liver disease, or kidney disease.

Osurnia® is to be used short-term in dogs and not for prolonged periods of time, as long-term use of topical ear medications containing corticosteroids has been associated with overactive adrenal glands.

Giving Osurnia® to dogs with certain medications can result in health risks to your dog, so always discuss your dog’s medications, including vitamins and supplements, and medical conditions with your veterinarian.

How Osurnia® Works in Dogs

Osurnia® has three active ingredients: florfenicol, terbinafine, and betamethasone acetate.

As an antibiotic, florfenicol works by binding to the genetic code of susceptible bacteria, which prevents the bacteria from making the essential proteins necessary for survival, growth, and replication. This leads to death of the bacteria, therefore treating the infection.

Terbinafine is an antifungal medication that works by blocking the susceptible fungus from creating a vital part of its cell membrane, resulting in death of the fungal organism.

Betamethasone acetate is a corticosteroid that reduces swelling, inflammation, and itching.

Osurnia® Directions for Dogs

Your veterinarian will follow the directions on the drug label.

Your vet will clean and dry your dog’s outer ear canal before administering the first dose (one tube) of Osurnia® in the affected ear. Your vet will repeat the administration of Osurnia® in seven days.

It is important not to clean the ear canal for 45 days after the initial administration to allow the gel to adhere and treat the infection.

To prevent your dog from scratching at their ears, which may delay healing and may cause further trauma and infection, your vet may recommend a recovery cone collar for your dog to protect the delicate tissues of their ears and face, and to prevent other pets from licking the medication.

Contact your veterinarian if your dog’s ear infection does not seem to be healing, worsens, or if the ear infection recurs after you have completed the treatment.

Missed a Dose?

If you forget to bring your dog in for their Osurnia® treatment, please contact your vet. In general, your veterinarian will schedule an appointment for your dog seven days after the first treatment to examine their ears, assess their response to Osurnia®, then administer the second treatment.

Possible Side Effects of Osurnia® in Dogs

Osurnia® is generally well tolerated in dogs. Some uncommon side effects may include:

  • Elevated liver levels
  • Vomiting

Long-term use of topical ear medications containing corticosteroids such as Osurnia® has been associated with overactive adrenal glands.

Instilling ear medication when your dog’s eardrum is ruptured can cause serious side effects associated with inner ear issues, including:

Contact your veterinarian immediately if your dog is experiencing any of these symptoms.

Human Side Effects

Osurnia® is a veterinary medication not intended for use in humans. Due to possible side effects, humans should never use medicine dispensed for their pets and pets should not be given any medicine dispensed for a human’s use.

If you accidentally ingest a veterinary medication, call your physician or the national Poison Control Center hotline at 800-222-1222.

Call Your Vet If:

  • Severe side effects are seen (see above)
  • Your pet’s condition worsens or does not improve with treatment
  • You see or suspect an overdose
  • You have additional questions or concerns about the use of Osurnia®

Osurnia® Overdose Information for Dogs

An overdose of Osurnia® is unlikely to occur, as this medication is typically administered in a veterinary clinic. If your pet ingests the topical medication, overdosage by mouth may suppress your pet’s immune system.

Prolonged use (longer than the maximum recommended treatment duration of two treatments seven days apart) or administration of too much medication (more than the recommended dosage of one tube full in the affected ear) may cause ear wetness, red/brown ear discharge, and elevated liver levels.

If you suspect an overdose, immediately contact your veterinarian, seek emergency veterinary care, or call an animal poison control center. Consultation fees often apply.

Pet Poison Helpline (855) 764-7661

ASPCA Animal Poison Control (888) 426-4435

Osurnia® Storage for Dogs

Osurnia® should be administered at your veterinary clinic. Osurnia® should be refrigerated at temperatures from 36 to 46 F for up to three months. Osurnia® may be brought to room temperature for your dog’s comfort during application.

Keep out of reach of children and pets.


What is Osurnia® for dogs?

Osurnia® is a prescription veterinary combination ear gel medication used in dogs to treat yeast and bacterial infections of the outer ear.

How long does it take for Osurnia® to work?

Osurnia® may start working within a few hours, but you usually will not see the effects of this medication right away in your dog’s ears. Your dog’s ear infection should start improving within one to two days.

Do you need a prescription for Osurnia®?

Yes. Osurnia® is only available by prescription through your veterinarian.

No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.

Molly Price, DVM


Molly Price, DVM


Dr. Molly Price has practiced small animal medicine for over 20 years and is a graduate of Texas A&M College of Veterinary Medicine. She...

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