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What is Neomycin Allergy?

Neomycin can only be obtained from your qualified veterinarian and works by suppressing the development and growth of protein synthesis; therefore, eradicating bacteria quickly. This drug is not absorbed into your cat’s body; in topical form it has a local effect and is often administered to eliminate infection such as on the eyes, skin and ears. Additionally, it works very well on intestinal infections, and in the same manner can rid the intestine of bacterial overload.

Neomycin should not be given to your cat if she has sensitivities or allergies as she may have an allergic reaction to it. Inform your veterinarian if your cat is on other medication or has any allergies at all.

Neomycin is an antibiotic medication used for cats for a range of bacterial infections and is especially effective for intestinal and skin infections. 

Symptoms of Neomycin Allergy in Cats

If your cat is hypersensitive then she may have a reaction to the medication; let your veterinarian know about her sensitivities.

  • Your cat may be affected by itching and redness of her skin, causing her to scratch and groom herself constantly
  • If your cat is allergic to this medication, you may notice that she is affected by eyelid twitching or swelling 
  • A swollen face, tongue or throat or any difficulty breathing, requires immediate veterinary attention
  • Your cat may exhibit Irritation and a generally depressed attitude
  • She may bump into things indicating a blurred vision 


  • Neomycin is a member of a class of drugs known as aminoglycosides
  • Neomycin comes in a wide range of topical cream applications
  • The creams usually contain 3 antibiotics (triple antibiotic ointment) – neomycin, polymyxin B and bacitracin
  • It isn’t used for cats with serious systemic infections such as pneumonia, or bloodstream infections
  • It is not absorbed by the body if it is applied topically or orally- its effect is strictly local only
  • As a prescription drug, it can only be obtained from your veterinarian

Causes of Neomycin Allergy in Cats

  • Although generally considered a safe medication to use because of its effect on bacterial infections, in some cases of hypersensitivity it may have an adverse reaction on your cat 
  • Too strong a dose can also produce reactions, always apply or administer any medication within the dosage and instructions as given by the veterinarian 
  • Other drugs that can potentially interact with neomycin sulphate are penicillin VK, vitamin K, methotrexate and digoxin 
  • Prolonged use of neomycin may produce resistance and allergy reactions

Diagnosis of Neomycin Allergy in Cats

Neomycin is used to treat infections (ophthalmic, intestinal and ocular) caused by bacteria, which can result in swelling or inflammation. Ensure you keep the medication sterile when treating your cat, do not touch the nozzle with your hands, or in the case of a topical application, touch the nozzle to the affected part of your cat. It is important to only apply the correct dosage of the topical or ophthalmic prescription, applying more is not better. It will not clear the condition up quicker. In fact, it may cause considerable harm to your cat. 

Similarly, with the oral medication, administration can cause an allergic reaction. Keep in mind that in rare cases, neomycin has resulted in reports of anaphylaxis following its use. As with all medications, it depends on the animal being treated. If your cat shows any unusual side effects contact your veterinarian immediately. 

Despite the ability to heal certain conditions, neomycin has been recorded as causing an allergic reaction and also side effects, such as head tilt or loss of balance may be seen. Your feline may have an immune system that is sensitive to compounds within this medication. When you arrive at the clinic, discuss the symptoms you have seen and the timeline of them. Your veterinarian will want to take blood tests in order to assess the adverse effect of the neomycin; the results, along with clinical signs, will confirm the reaction.

Treatment of Neomycin Allergy in Cats

Depending on the stability of your pet when he arrives at the clinic, the veterinarian may choose to admit him for therapy and monitoring.

In the case of a topical or ophthalmic reaction, the veterinary team will gently bathe the skin or rinse your cat’s eyes in an attempt to remove the product. Diarrhea has been recorded as a common effect in cats that may be seen with this medication, and particularly in the event of dehydration, the veterinarian will want to administer fluids by intravenous. 

The veterinarian may want to keep your cat under observation until it is confirmed that the allergic reaction has been attended to completely. The fluids will flush the kidneys and with this effect, your pet should begin to feel better. As well, the team will assess the condition of your pet’s skin or eyes in the case of an epidermal or ocular reaction, to ensure that the reaction is beginning to subside.

Recovery of Neomycin Allergy in Cats

Recovery depends upon the severity of your cat’s condition and your cat’s health. Younger cats tend to recover more quickly than elderly cats. Once home, provide your cat with a clean, quiet environment in which to rest.

Neomycin Allergy Questions and Advice from Veterinary Professionals

Domestic shorthair
6 Weeks
Mild condition
0 found helpful
Mild condition

Has Symptoms


My cat nova had an eye infection and we were prescribed the neomycin and she recovered very quickly, but about a week or so after shes developed a bit of balding near her ears and in her whiskers region on the face. Could this be a reaction to the medication?

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3 Months
Serious condition
2 found helpful
Serious condition

Has Symptoms

Head Tilt

Hi , i used eye drops for a 3 month + old female kitten for an eye infection and a couple days later she had a head tilt. I didn't realize it could be from the eye drops which contain neomycin , what can I do to help her get better and if it is possible for the head tilt to go away. This happened before for 2 kittens previously when i used gentamycin eye ointment but didn't know the cause , the vet told me it was probably genetic and there was no cure. But now I am linking the two cases to sensitivity to the eye drops and eye ointment which contain neomycin and gentamycin relatively. I would really appreciate your help. Thanks, Waad

Dr. Michele King, DVM
Dr. Michele King, DVM
1611 Recommendations
Waad, thank you for contacting us about Truffles today. I am sorry that has happened to Truffles. It is definitely an unusual reaction to a very commonly used eye medication for infection and upper respiratory disease. Time will tell if the head tilt will resolve, but younger kittens do tend to respond better than older cats in these cases, and once the eye medication has left your cats system, you should start to see signs of improvement. If you don't see improvement over the next 2-3 days, it would be a good idea to have Truffles rechecked by your veterinarian. There may be other causes for the neurologic signs, like Neospora or Toxoplasmosis, and a good neurologic exam needs to be performed. If Truffles stops eating, starts vomiting or having diarrhea, a visit to your veterinarian sooner vs later would be a good idea. It may indeed be a genetic mutation, especially if all the cats affected were related. I hope that Truffles recovers uneventfully.

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domestic short hair
15 Years
Moderate condition
1 found helpful
Moderate condition

Has Symptoms

Deafness or hard of hearing

Medication Used

Quadritop & Dexasporin

I think neomycin in my cat’s prescribed ear ointment caused her to become deaf. My vet thinks it is temporary but it has been 3 weeks and her hearing is maybe intermittent at best. I hesitate to say she is totally deaf but I can tell she can’t hear normally. She was prescribed eye drops today that contain neomycin for conjunctivitis which is what I originally brought her in for 3 weeks ago. The other eye meds didn’t work; they were for an assumed chlamydia flare which she has had before. I don’t want to use the new eye drops. I think she might be allergic. Am I crazy?

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4 Months
Serious condition
1 found helpful
Serious condition

Medication Used

Clavamox antibiotic- oral
polymycin b sulfates
bacitracin zinc

My kitten is having a severe reaction to neomycin polymysin b sulfate bacitracin ointment he was prescribed by vet for conjunctivitis. Nictitating membrane is very swollen after one dose of this ointment

what other ointments could I use instead?

Dr. Michele King, DVM
Dr. Michele King, DVM
1611 Recommendations
There are many medications that can be used in cats, and BNP is a common one. If Olivier is having a reaction, it would be best to follow up with your veterinarian to see what medication might help, as I don't know what condition was being treated initially and can't see his eyes. They'll be able to assess him and get the best treatment for him. Since he does seem to be reacting to the ointment, however, it would be best to discontinue it until you see your veterinarian.

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