Fluocinolone Acetonide & Dimethyl Sulfoxide (DMSO) Otic Solution

By Krista Williams, BSc, DVM, CCRP

What is fluocinolone acetonide + dimethyl sulfoxide (DMSO) solution?

Fluocinolone acetonide + DMSO (brand name Synotic®) is a combination anti-inflammatory agent used in the treatment of otitis-related ear inflammation and itching in dogs and cats. Its use in cats is off-label. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions carefully.

How is fluocinolone + DMSO given?

Fluocinolone acetonide + DMSO is a liquid that comes in a bottle with a dropper tip and is applied topically to the ear canal. It is best to administer it after the ear has been cleaned. You may need assistance when administering ear drops to your pet (see handouts “Applying Ear Drops to Cats” and “Applying Ear Drops to Dogs” for tips).

  • Tilt your pet’s head so that the affected ear is facing upwards. Administer the amount recommended on the prescription label. Your veterinarian will indicate the number of drops to be applied. Gently massage the ear to ensure that the medication is evenly distributed.
  • If your pet is getting other ear medications, check with your veterinarian about which medication to give first and how much time to allow between giving medications.
  • Avoid contact with your pet’s eyes, nose, and mouth.

This medication will take effect quickly, in about one to two hours, but visible effects may take a few days to be noticed.

What if I miss giving my pet the medication?

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

It is important to give the medication for the length of time your veterinarian has recommended, even if your pet appears to feel better.

Are there any potential side effects?

A full veterinary assessment is essential before starting this medication to minimize side effects.

A side effect of any ear medication is hearing loss. Temporary vestibular disorders causing a head tilt, walking in circles, or an unsteady gait, especially in cats, can also occur with the application of any ear medication. If you notice your pet is having difficulties with balance, stop using the medication and contact your veterinarian.

Fluocinolone acetonide + DMSO may cause short-term discomfort when applied to ulcerated areas of the ear, but that will decrease over time as the ear heals. If redness or discomfort continues with application, your pet may be experiencing an allergic reaction to the medication. Stop applying the medication and contact your veterinarian.

DMSO can cause poor smelling oyster- or garlic-like breath.

Fluocinolone is a corticosteroid that may have effects on the whole body, even when only applied to the ears. Stop treatment and contact your veterinarian if you notice signs of steroid sensitivity in your pet including decreased appetite, vomiting, diarrhea, increased thirst, and urination. Chronic use of corticosteroids like fluocinolone can also cause thinning or tearing of the skin, hair loss or infection. Any indication of these effects should be reported to your veterinarian immediately. This medication is not recommended to be used for more than 14 days at a time.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Fluocinolone acetonide + DMSO should not be used in pets with hypersensitivities (allergies) to corticosteroids or DMSO. It should not be used in pets that are pregnant or that have a ruptured ear drum. It should be used with caution in pets with very sore or ulcerated ears or ear infections.

Humans should avoid contact with eyes and skin. Wear gloves when applying it to your pet and wash your hands after application. In case of contact with the skin, wash with soap and water. In case of contact with eyes, flush with water for 15 minutes. Contact your doctor if irritation develops or persists.

Are there any drug interactions I should be aware of?

Certain drugs may interact with Fluocinolone acetonide + DMSO. It is important 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?

Monitor to ensure that the medication is working and for adverse effects, such as problems with balance or hearing loss. Your veterinarian will recommend when to bring your pet for a follow-up examination, which is necessary to assess your pet’s response to treatment.

How do I store fluocinolone acetonide + DMSO?

Fluocinolone acetonide + DMSO should be stored in a tightly sealed container, between 68°F and 77°F (20°C-25°C) and protected from direct sunlight. It is important to store the bottle in an upright position. If this medication has been compounded, follow the directions on the label for storage.

Do not use leftover medication without approval from your veterinarian.

What should I do in case of an 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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