Warning: Risk of Deafness from Ear Medications

[k9diabetes]

Sadly, I can now list a fourth dog who has gone deaf due to treatment with an ear medication containing Gentamycin.

From Pet Education, http://www.peteducation.com/article.cfm?cls=0&cat=1461&articleid=3255 regarding Gentamycin:

Gentamicin/Betamethasone-Otic (Gentocin® Otic, Otomax®)

Gentamicin is an antibiotic of the aminoglycoside class. Betamethasone is a corticosteroid. The combination is used for the treatment of inflammation and bacterial infections of the ear. Products with clotrimazole are also effective against fungal (yeast) infections of the ear. A veterinary exam of the ear is necessary prior to use of this product in the ear. It should not be used in animals with a perforated eardrum. . .

Contact your veterinarian if your pet experiences a loss of hearing or balance while being treated with gentamicin. These effects are usually temporary. Do not use in animals who require their hearing to perform their work (military dogs, police dogs, seeing eye dogs, hearing dogs, etc.) as the hearing or vestibular (balance) impairment may not be reversible.

From Medi-Vet, http://www.medi-vet.com/detail.aspx?ID=2965:

Each gram of OTOMAX® contains gentamicin sulfate veterinary equivalent to 3 mg gentamicin base; betamethasone valerate, USP equivalent to 1 mg betamethasone; and 10 mg clotrimazole, USP in a mineral oil-based system containing a plasticized hydrocarbon gel. . . .

The use of OTOMAX® has been associated with deafness or partial hearing loss in a small number of sensitive dogs (eg, geriatric). The hearing deficit is usually temporary. If hearing or vestibular dysfunction is noted during the course of treatment, discontinue use of OTOMAX® immediately and flush the ear canal thoroughly with a non-ototoxic solution.

I do not know of any dog that regained its hearing though I'm sure the ears weren't flushed in response either as some time passed before owners realized the dog was deaf and made the association with the medication.

From The Complete Home Veterinary Guide, Chris C. Pinney:

If a ruptured eardrum is suspected, selection of treatment agents must be done carefully. For example, antibiotics belonging to the class known as aminoglycosides (examples include gentamycin and neomycin) should not be used in the ear directly since they can cause nerve deafness if exposed to the inner ear. The same holds true for astringent preparations and acetic acid solutions. In addition, if a ruptured eardrum is suspected, only water-soluble treatment solutions should be used. Ointments should be avoided as they can become entrapped within the middle ear.

This is particularly important for diabetic dogs like Chris, who are/were already blind and didn't need to lose another sense.

I was never warned by a veterinarian about this risk. Chris' vet did look into his ear first before prescribing it and once I knew about the risk we only used the medication when absolutely necessary and avoided Gentamycin products (he was allergic to Neomycin).

But other otic products contain similar warnings and in general it seems all of them should be kept from going deeply into the ear when possible.

[We Hope]

Natalie,

This class of antibiotics comes in many forms--inhalation and parenteral (by injection) as well as preparations for the ears.

http://www.drugs.com/cons/gentamicin-systemic.html

"Aminoglycosides given by injection are usually used for serious bacterial infections for which other medicines may not work. However, aminoglycosides may also cause some serious side effects, including damage to your hearing, sense of balance, and kidneys.

"Other medical problems—The presence of other medical problems may affect the use of the aminoglycosides. Make sure you tell your doctor if you have any other medical problems, especially:

"Loss of hearing and/or balance (eighth-cranial-nerve disease)—High aminoglycoside blood levels may cause hearing loss or balance disturbances"

I learned first-hand what this type of antibiotic can do when I was very young; our Sheltie (Lucky) suffered permanent loss of her hearing because of its use. The "vet" at the time never spoke a word about this possibility when giving her an injection of this sort.

We knew she was able to hear from the beginning--then she suddenly stopped being able to do that. I don't believe the "treatment" cleared up the infection she had, as she completely lost control of her bladder. To make matters worse, the "vet" had hit a nerve with this injection, causing a palsy and loss of use of one of her front legs. Friends of the family suggested getting another doctor to help her.

My parents left me home when they took this little puppy elsewhere; they were afraid she wouldn't be coming back--so was I. She got treated for her very bad UTI and didn't need to stay at the hospital--this was the first of many years of visits to "Grampa".

He told them that indeed, she'd lost her hearing from it and there was no way to restore it and that she had heretofore undiagnosed epilepsy (we saw no seizures). He suggested daily massage for her leg, which had atrophied somewhat. The question of quality of life came up--he told them she sure had that, but that she probably wouldn't live past 5 years of age with all of her problems.

We developed a method of hand signals for communicating with her, the massage restored the leg so that it no longer shook and she could use it normally, and her daily medications kept her from ever having a seizure. She lived to be 11 years old.

This is Lucky--you see how well she did.

Kathy

[Debbie & Apollo]

wow !

thanks for posting -- I bet you can guess what ear medicine Apollo is using!!!!

too late to call the vet tonight....

if it's not one thing it's another.

thanks for the info --

APOLLO! and Debbie

[bowens2]

Monk too and I suspect he has lost hearing in at least one ear.

Thanks for that info.

[Debbie & Apollo]

OK --

We have had Apollo in already for a few quick checks up since we started this med - I thought it was to see how he was doing but the vet has been looking at the eardrum very closly. There are other medications but with the diabetes -- well that just complicates things! as if we didn't know that

he goes back on Tuesday -- things are looking much better from my perspective so I think we'll be able to stop the med.
Also am much better at cleaning his ears! It takes time but it will be worth it in the end.

thanks for the watching out for the furbabies!

Debbie and (all ears - Apollo)

[Denise]

I just saw this post. Had posted today about an ear med many are using in their diabetics that contains gentocin and also an antifungal and cortisone.

I had a dog go deaf from gentocin and the warnings for all the ingredients in Mometamax are pretty scary even for human use.

[k9diabetes]

Hey Denise,

Patti's Max and Helen's Honey are two of the dogs this has happened to in the past couple of years.

With your dog and Kathy's dog, that brings the count to seven with Monk possibly being number eight...

I really hate this drug and how thoughtlessly it's dispensed. I suspect that vets are told that it's a very rare occurrence and that's why they haven't worried much about it but this is NOT something I would call rare and I would always want the option to weigh different treatment approaches against the risk from this one.

[We Hope]

A short cruise on PubMed indicates that this class of antibiotics was first produced in the 1940's-1950's. It fell out of favor in the 1960's-1970's when it's potential ill effects on hearing became widely known. It's still around with both people and pets because of its "cost effectiveness".

A theory re: why it can rob people of their hearing is that some people have a gene predisposing them to hearing loss when given this class of antibiotics. I read about an Italian family who had 5 members lose their hearing when being prescribed these drugs. Also read that it's used to treat eye problems and that some suspect it of causing macular degeneration in some patients.

So the situation is the same with human medicine--being prescribed with apparent small regard to its possible consequences re: hearing.

FWIW-

http://www.ncbi.nlm.nih.gov/pubmed/17266591

Aminoglycoside-induced ototoxicity. Current Pharmaceutical Design 2007

"It has long been known that the major irreversible toxicity of aminoglycosides is ototoxicity. Among them, streptomycin and gentamicin are primarily vestibulotoxic, whereas amikacin, neomycin, dihydrosterptomycin, and kanamicin are primarily cochleotoxic.(They describes the area of the ear each antibiotic affects.) Cochlear damage can produce permanent hearing loss, and damage to the vestibular apparatus results in dizziness, ataxia, and/or nystagmus. Aminoglycosides appear to generate free radicals within the inner ear, with subsequent permanent damage to sensory cells and neurons, resulting in permanent hearing loss. Two mutations in the mitochondrial 12S ribosomal RNA gene have been previously reported to predispose carriers to aminoglycoside-induced ototoxicity. As aminoglycosides are indispensable agents both in the treatment of infections and Meniere's disease, a great effort has been made to develop strategies to prevent aminoglycoside ototoxicity. Anti-free radical agents, such as salicylate, have been shown to attenuate the ototoxic effects of aminoglycosides. In this paper, incidence, predisposition, mechanism, and prevention of aminoglycoside-induced ototoxicity is discussed in the light of literature data."


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http://www.ncbi.nlm.nih.gov/pubmed/1...gdbfrom=pubmed

Ototoxic drugs. I. Aminoglycoside antibiotics Wiadomoski lekarskie (Warsaw,Poland)

"The fact that some drugs can affect the hearing function is well known. All aminoglycoside antibiotics have the potential to induce severe and irreversible ototoxicity in the cochlea and vestibular organ. The mechanism causing aminoglycoside-induced hearing loss is still not well established. Nevertheless, today aminoglycosides are the most commonly used antibiotics world wide thanks to their high efficacy and low cost. In this review pharmacological and toxicological properties of aminoglycoside antibiotics are described as well as risk factors and pathophysiology of aminoglycosides ototoxicity. Current hypotheses concerning the mechanisms of aminoglycoside-induced ototoxicity are also discussed."

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Kathy

[Glenda12]

Natalie,

Just checking out this board and came across this post. Thank you so much for posting it. You guessed it, this is the medication we use for Buddy. I'm kind of upset that we were never informed of any of these side effects. This really works for his ears too damn it. The other Sulfalor (??) did nothing for him.

I guess you may wonder....the vet said it was a great anti-inflammatory and if we put is on his "elbows" it would help with itching....indeed it does. We've also found that on his bum, when he has itchies to the point where he rubs the hair off and he gets a kind of hardened skin, I'm put it on there for a few days and it seems to clear it up. I guess I've really never thought, that if it is this potent, may not be so good for the ears.

Will not be using this for his ears anymore. Will keep it for use on the bum and elbows though.

Thank you again for the info.

[Debbie & Apollo]

Hi -- ok just back from rechecking Apollos ears ---
we have switched his ear meds to Tresaderm, it has to stay in the refrig.

Debbie and Apollo