Mometamax is a prescription ear drop medication for dogs that treats ear infections caused by bacteria, yeast, or both. It combines three active ingredients: an antibiotic (gentamicin), an antifungal (clotrimazole), and a steroid anti-inflammatory (mometasone furoate). Together, these ingredients fight the infection while reducing the swelling, redness, and pain that make ear infections so uncomfortable for dogs.
What Mometamax Treats
Mometamax is specifically designed to treat otitis externa, which is an infection or inflammation of the outer ear canal. This is the most common type of ear problem in dogs, and it can be triggered by bacteria, yeast overgrowth, or a combination of both. Dogs with floppy ears, dogs that swim frequently, and breeds prone to allergies tend to develop these infections more often.
The medication works on three fronts simultaneously. The antibiotic component kills susceptible bacteria in the ear canal. The antifungal component targets yeast organisms that commonly colonize inflamed ears. The steroid reduces inflammation, which eases pain, decreases swelling, and helps the ear canal open up so the other two ingredients can reach the infection more effectively.
How It’s Given
Mometamax is applied directly into the affected ear canal once daily for 7 consecutive days. The dose depends on your dog’s size:
- Dogs under 30 lbs: 4 drops per affected ear (2 drops if using the larger 215g bottle, which has a bigger dropper)
- Dogs 30 lbs or more: 8 drops per affected ear (4 drops from the 215g bottle)
After applying the drops, gently massaging the base of the ear helps distribute the medication deeper into the canal. Most dogs show noticeable improvement within the first few days, but finishing the full 7-day course is important even if symptoms seem to clear up early. Stopping short can allow resistant organisms to survive and cause a rebound infection.
The Eardrum Check Before Treatment
Before prescribing Mometamax, a veterinarian needs to examine the ear canal to confirm the eardrum is intact. This step is not optional. If the eardrum has a hole or rupture, the medication can pass through into the middle and inner ear, potentially damaging the structures responsible for hearing and balance. That’s why Mometamax is never dispensed without a veterinary exam first, even if your dog has had ear infections before and you recognize the signs.
Possible Side Effects
Most dogs tolerate Mometamax well, but side effects can occur. The most common reactions are localized: redness, swelling, itching, or irritation at the application site. These are typically mild and resolve once treatment ends.
A more serious but less common side effect is hearing loss. This has been reported in a small number of dogs, particularly older or sensitive individuals. The hearing loss is usually temporary, but any sign of deafness, head tilting, circling, or loss of balance during treatment warrants an immediate call to your vet. These symptoms can indicate that the medication is affecting the inner ear’s balance and hearing organs.
Because Mometamax contains a steroid, prolonged use or accidental ingestion of the bottle can trigger systemic effects: fluid retention, weight gain, increased thirst, and increased urination. Extended courses can also suppress your dog’s natural hormone production and weaken immune response over time. This is one reason the standard treatment is kept to just 7 days. If the infection hasn’t improved by day 14, the vet will typically reassess and consider alternative treatments rather than simply extending the course.
Not Safe for Cats
Mometamax is approved for use in dogs only. The labeling explicitly states it should not be used in cats. If you have a cat with an ear infection, your vet will prescribe a different medication formulated for feline use. This is not a case where a smaller dose might work. The product carries a clear warning against feline use entirely.
Why It Requires a Prescription
You cannot buy Mometamax over the counter. It requires a veterinary prescription because the underlying cause of an ear infection matters for treatment. Bacterial infections, yeast overgrowths, ear mites, and foreign bodies can all look similar from the outside, but they need different approaches. A vet will typically take a swab of the ear discharge and examine it under a microscope to confirm what organisms are present before choosing Mometamax or an alternative. The eardrum integrity check adds another layer of safety that can only happen in a clinical exam.
If your dog’s ear infections keep coming back after treatment, the underlying trigger (allergies, anatomy, moisture buildup) likely needs to be addressed alongside the infection itself. Recurring infections treated only with ear drops tend to become harder to resolve over time as organisms develop resistance.