Transdermal Methimazole Treatment For Hyperthyroid Cats

Katie, hyperthyroid. Bless her.
Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats

Katie, hyperthyroid. Bless her. Photo Alan Turkus

I’ll get straight to the point. Transdermal Methimazole treatment works but ask your vet. That is the general conclusion. I had to check. There has been a useful clinical study on this. They concluded:

“Clinical improvement, as well as a significant decrease in T4, was noted in all cats.”

T4 means serum thyroxine levels. In layman’s language the treatment reduced the amount of thyroid hormone in the cat, which is the objective because hyperthyroidism is an excess of the hormone due to over-production.

This video show how to apply the drug and clean the cat’s ears because the gel builds up. Ear cleaning should be done carefully and this presenter is careful and thoughtful. The interesting aspect of this is that the drug is absorbed through the skin and where the skin is thin allowing absorption into the bloodstream is the ear flap (the bit of the ear that you see). Applying drugs this way is called “transdermal” meaning via the skin.

There are of course some negatives to this one of which is that the ears need cleaning.  The video also covers this. The gentleman presenter has a very gentle and sensible approach which is ideal.

Hyperthyroidism is most common in middle-aged and older cats caused by these environmental factors. The prevalence is 0.33%. This means a third of one percent of all cats get it; quite a high figure when you work out the numbers – about 3 million domestic cats in the USA.

Transdermal application avoids “oral daily administration” which I presume means giving pills to a cat – hurrah! Incidentally the treatments listed on the top website (Google search) for this feline condition does not refer to transdermal methimazole. They list treatment with radioactive iodine and surgical removal of the affected thyroid gland as alternatives to oral medication.

Another benefit of this method that it requires a lower dose can be used:

“a lower dose of methimazole can be used to obtain an equivalent plasma concentration and clinical effect, with reduced risk of side-effects”

A concern is whether this treatment damages the delicate skin of the ear. Apparently the study found that it did not except for one of 13 cats. To quote:

“no cutaneous reactions were noted at the site of the application of the methimazole gel during the length of the study”

The assessment is qualified by saying that they can’t be sure there won’t be some problems in the long term. Always ask your vet about treatments such as this as they should be up to date.

Useful tag. Click to see the articles: Cat behavior

Note: sources for news articles are carefully selected but the news is often not independently verified.
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Michael Broad

Hi, I'm a 74-year-old retired solicitor (attorney in the US). Before qualifying I worked in many jobs including professional photography. I love nature, cats and all animals. I am concerned about their welfare. If you want to read more click here.

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12 Responses

  1. Caroline says:

    This is quite uncommon amongst cats, as you know. Taurine in the diet is important. This is quite common, though, with veterinarians checking for hyperthyroidism. It’s basic, as far as testing. But the occurence is rare. You are right, Michael. It still needs to be addressed. It is quite possibly a solution with some cats. Every symptom should be addressed. There are more important issues that should be addressed first. Focus on those.

  2. I can’t take my 5 year old male tomcat “Matata” to the vet as it is akin to trying to tame a miniature leopard!He is absolutely nervous of strangers and would scratch or bite if forcibly put into a enclosed “Cat Box”.Since his birth he has never ever been taken to a vet and luckily till date he is normal,. He has been suffering from some strange “Skin Disease” caused by flea infection and i have been bathing him with anti-flea shampoo.His entire fur sheds akin to a dead animal being skinned.I can’t take him to a vet to understand the reasons for his skin peeling off and the vet doesn’t attend pet patients at home.I totally agree with Mark that Veterinarian doctors should try to make home visits if possible.I have posted a photo of “Matata’s” shedding fur.Notice the parting of the fur mat near his hind leg. I gave him a bathe yesterday and cut off the hanging fur mat which resembles a small carpet !Thanks to “P.O.C” at least we can learn from our own cats and discuss their ailments.

    • as it is akin to trying to tame a miniature leopard!

      That made me laugh. You are not alone. There is a new service in the UK called Talk To The Vet. You can get one to one Skype consultation for a fixed fee. That would probably suit you! But I am not sure it will work.

      Rudolph I can’t figure out the orientation in the photo. Are you saying he sheds lots of fur? Is his skin OK? Are red bumps etc.? Does he scratch his skin? Remind me how old he is, Rudolph, please. If you can get a fresh picture I’ll try and give you some ideas. You might try the talk to the vet link above. You’ll get a British vet! The best … 🙂

      • Michael,his skin is perfect and there are no lesions or red swellings as in dogs having scabies.His fur is growing back in places where i have removed the matted fur.He is absolutely normal, hale and hearty. Just wondering as to the type of this unusual disease of skin shedding akin to a snake.He is 5 years old.
        Below is a photo of “Matata” after the bathe and removal of “Dead Skin” from his hind thighs.

        • Hi Rudolph, I have not read about skin shedding akin to a snake. Sounds like dry skin. If he is healthy, was this skin condition present before you started using the shampoo? I presume it was. You think it is caused by the fleas. I don’t think it is. Flea bit allergy causes red lumps due to an allergic reaction. I would have remembered peeling skin in the books use. Thyroid conditions can cause flaky skin but I wonder if the shampoo might be a factor. Why not try a flea spot treatment (Frontline for example) and stop the shampoo?

          • Michael,thanks for the suggestion.Even i suspected the “Anti-flea shampoo”.I will stop using the same.He is otherwise perfectly normal,hale and upto his pranks.Here is a view of his peeled fur which resembles a “Skinned animals fur”.It just peels off from his skin.

            • I see what you mean now. Clear to me at last! 😉

              Matted fur – but it shouldn’t peal off like this. The obvious choice is to stop the flea treatment shampoo and see what happens.

              This is a new problem and the only change in his lifestyle is the shampoo as far as I know.

              Fleas per se don’t cause this. Another possibility is this: matted fur is heavy because it is dense. It may be connected to the skin by relatively few hair strands which under the weight give way and release the entire wad of hair. Just a thought.

    • kylee says:

      Yes its great to be able to talk with each other about probs affecting our cats and help each other out.

  3. marc says:

    Not sure I could easily give my cats any kind of medication. They are not used to being handled and pushed so it would be quite difficult no doubt. I think it might even be almost impossible depending on what I’m trying to do. I would not be able to force them to swallow pills or accept an ear cleaning.

    Since we are on the subject of medicating cats – it’s important that cats be treated totally differently to dogs in these scenarios. Actually – I think that for regular checkups, boosters, even taking blood for tests or other basic procedures – vets should go to the homes. Infact I think they must. Cats shouldn’t travel. In Canada we had a great Indian vet who would come to the house for many things. It was such a relief. And he charged low prices. I’m sure you can guess that he basically had a full timetable of customers. Everybody wanted him. He could take all the business he wanted with a service like that.

    Cats need vets like him. Cats get sick when they are stressed. Taking a sick cat regularly to the vet is an awful thing to have to do to a sick cat. There’s a hugely unfair balance of money, research and activity in the vet industry – and cats are on the loosing end. Dogs have always taken first place. There should be more cat only clinics too.

    Putting cream on their ears would take me quite some time. It might take me a month or so to be able to do it properly.

    • kylee says:

      I guess some would come but it would be a big cost esp if was after hours. Thankfully the local Vet is just down the road like 5 mins away. I learnt how to give worming tablets and antibiotics. The vet here explained and showed how to do it. So feel kind of Lucky. We take our cats in a large size Cage they hate going to the vet, but seem OK once we are there with them. I dont know about this situation as experienced it, but there was some talk before Cassy had got sicker they thought she may of had that. It would be nice if there were just Cat Vets

    • Ruth aka Kattaddorra says:

      A disabled friend who is an amputee in a wheelchair, phoned the vets, the same practice we use, as he was a bit worried about his cat. For a vet to call out at his house would be £80 plus the treatment.
      We were at the vets with Walter yesterday and it cost us almost £70 so going by that it would have cost our friend around £150.
      His carer called for a tube of Katalax which thankfully put his cat right, it must have been hairball trouble.
      People just can’t afford to call a vet to the house in our area.

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