Hi, I have a 9 year old cat who is currently on methimazole for hyperthyroidism. I am concerned about side effects he is experiencing. His dosage is still being adjusted. His last blood work indicated high creatin levels. Tonight I am taking him for more blood work and they will take a urine sample. This puts him under a lot of stress as well and he is a very unhappy kitty. I am looking for alternatives that are not so hard on him.
Any suggestions?
You have two choices besides methimazole therapy. The first is having him treated with I 131 (radioactive iodine), and the second is surgical removal of the thyroid tumor. Prior to proceeding with either of these therapies however, you should make absolutely certain a euthyroid state does not put the cat in renal failure. The hypertension associated with hyperthyroidism increases blood flow to the kidneys and may in some cases mask renal failure in hyperthyroid cats. All hyperthyroid cats should have methimazole therapy until the euthyroid state is reached, and the have the kidney function monitored. If therapy causes the underlying renal failure to become exposed, you need to walk a fine line between treating the hyperthyroidism and renal failure. This is sometimes a very difficult thing to do, and makes I 131 therapy or surgical thyroidectomy less desirable alternatives to methimazole administration.
Mike Keem, DVM
Aurora Pet Hospital
East Aurora, NY
Hi – If your cat’s renal values (creatinine, BUN, PO4, etc.) are not too high, ask your vet about radiation treatment. I know it sounds horrendous, but all it takes is one subcutaneous (under the skin) injection of I-131 (radioactive iodine) and the “bad” thyroid cells are eliminated. My own cat has had this done, and I have sent many of my clients for this procedure. Your cat will need a full blood workup, urinalysis, and probably a chest x-ray first to make sure he’s a good candidate for this. Then the only hard part is that he will have to stay in the facility for 4-6 days to let the radioactivity dissipate out of his body. In 98% of cases, the cats never need any more treatment and are perfectly fine. Remember that the main contraindication for this is elevated renal enzymes, so depending on your cat’s levels, this may not work for him. But it’s worth asking about. It has to be done in a special facility because of the use of radiation – try googling “Radiocat”, which is one of the larger groups that dose this, to see what’s available in your area. Good luck –
Jo Ann Greenberg VMD
Atlantic Animal Care
Brooklyn, NY
There is an alternative, but your cat must be regulated on the methimazole first. Talk to your veterinarian about I-131. This is a one time injection that kills the over active thyroid tissue. The downfall is they have to stay in isolation for up to 2 weeks, but it is definitely worth it. There is a very low reoccurence rate of hyperthyroidism with this injection. If my cat ever developed the disease I wouldn’t think twice about the injection once they were regulated on the methimazole. The purpose of regulating them first is to make sure there are not significant underlying kidney problems that were masked by the hyperthyroid disease. You can always ask your veterinarian for a referral to a specialist or a university.
Good luck,
Tammy Evans, DVM
Caring For Life, Inc.
Cocoa, FL
Likely a difficult case. The methimazole is not causing the creatinine to increase. Rather, treatment of the hyperthyoidism with methimazole has unmasked the underlying renal disease your cat already had (you have been told your cat has renal disease, right?)
Untreated hyperthyoidism hides renal disease by increasing blood flow to the kidneys.
Now, you have to partially treat the hyperthyoidim with methimazole to prevent her kidneys from failing. Understand?
Philip McHugh, DVM
Park Veterinary Hospital
Durham, NC
The only alternatives I know of are I-131, which is the radioactive iodine treatment, or surgery to remove the thyroid glands. The methimazole is usually the easiest on them, but there is now a service called Radiocat which now does the I-131 in a day or so vs. 3-5 days in isolation at a referral center. You might look them up on the web to find the nearest location.
Best of luck,
Joy N. Ritz, DVM
Decatur Veterinary Clinic
Indianapolis, IN
Have your vets recommended or suggested using radioactive iodine treatment? It is expensive up front and your pet will need to stay in a hospital for 7-14 days, but you will not have to worry about giving oral medication ever again and your pet will be stabilized quite nicely.
Something to consider. I have sent over a dozen cats to have it done and everyone has thanked me afterwards.
Mark Helvie, DVM
Dahlonega Veterinary Hospital
Georgia
If your cat is only nine years old, and the urine test shows good specific gravity (over 1.040) then I would recommend you consider radioactive iodine treatment. It is considered a cure for hyperhyroidism, and is very non-invasive (they are given an injection of the radioactive iodine under the skin). The drawback is that they are radioactive for a few weeks. They stay in the hospital or treatment facility usually for 3-4 days, then have some special handing requirements for 2 weeks, but most do very well and need no further treatment for thyroid disease. It is expensive, and not available in all areas, so you may need to talk to your vet for help finding a treatment center or university that does it close to you.
I have 2 cats that were treated, and it was the best thing I ever did for them! No fighting with medication or driving them in for lab work every 3 months.
Dr. Lori
Lori L Coughlin, DVM
Arlington Heights, IL
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