Use of Methimazole transdermal gel

RE: Use of Methimazole transdermal gel

Lindsey Edwards — Mon, 28 Mar 2016 19:34:15 GMT

Iodine restricted cats improve and cats in iodine depleted areas do not seem to succumb - it has been theorised there may be a connection, indeed this link was the idea behind y/d development. It will remain theory until proved or disproved. Surely in unstable cat all options are worthy of consideration and least invasive options should definitely be included in complementary options prior to surgery with associated risks even if not guaranteed. Diet can always revert if desired

RE: Use of Methimazole transdermal gel

Martin Atkinson — Thu, 24 Mar 2016 18:55:31 GMT

[quote user="villagevet"]Is cat on Y/D alongside medication - would this make control easier? [/quote]The issue is getting them to eat it. I've had cats that have been controlled completely others that refuse to eat it.

[quote user="villagevet"]

Hyperthyroidism is not something I meet often, it does seem to have quite a regional distribution - possibly due to iodine levels and environmental factors?

Anecdotal but for any inside/outside cats here all prey is going to be iodine depleted as per prevalent soil type and environment and we don't see many 'housecats' solely on commercial food. Indeed the only hyperthyroid cats I have treated have not originated in our locality - baseline iodine levels kept low?

[/quote]There are many theories on epidemiology and none are proven. There is no regional pattern, it is not sex or breed related, indoor and outdoor cats are equally affected. AFAIR from the latest CPD, the only one that seems to be of any significance is cats that are fed on a high fish diet or fishy cat foods.

RE: Use of Methimazole transdermal gel

Lindsey Edwards — Thu, 24 Mar 2016 18:45:02 GMT

Is cat on Y/D alongside medication - would this make control easier? Hyperthyroidism is not something I meet often, it does seem to have quite a regional distribution - possibly due to iodine levels and environmental factors?

RE: Use of Methimazole transdermal gel

Martin Atkinson — Thu, 24 Mar 2016 18:17:35 GMT

[quote user="robloxley"]On which basis I am slightly less worried about people crushing felimazole[/quote]I'm not all worried. I advise clients that I cannot advise that they crush the tablets as there is a minuscule risk and women of child bearing age should be especially careful but you would have to be pretty careless, sniff the powder or lick your fingers afterwards to get a dose. Read between the lines.

RE: Use of Methimazole transdermal gel

Rob Loxley — Thu, 24 Mar 2016 15:32:20 GMT

[quote user="Sarah Keir"]And the owners and anyone else that comes into contact with the cat can get a nice dose too![/quote]

On which basis I am slightly less worried about people crushing felimazole and mixing in found (obviously not if pregnant/trying to get so...)

RE: Use of Methimazole transdermal gel

Sarah Keir — Thu, 24 Mar 2016 12:37:54 GMT

And the owners and anyone else that comes into contact with the cat can get a nice dose too!

RE: Use of Methimazole transdermal gel

Martin Atkinson — Wed, 23 Mar 2016 18:39:03 GMT

[quote user="Emily Rainbow"]

I have one cat who comes in to have his ears clipped by a nurse regularly as he's on a higher dose to help with area for absorption?

[/quote]This has been posted up on here before, but in one CPD course I went to the speaker said they put some blue dye in the gel before applying it to the ears and within a short time the cat's coat was a shade of pale blue. It seems many cats will groom the gel off the ears and absorb it orally so putting it anywhere on the coat the cat can lick may be as effective.

RE: Use of Methimazole transdermal gel

Liz w — Wed, 23 Mar 2016 18:08:42 GMT

I've not come across this before. Does it get absorbed quickly and what guidelines do you give the owners re handling the cats after it's been applied? Is it just a case of "don't touch their ears"?

RE: Use of Methimazole transdermal gel

Emily Rainbow — Wed, 23 Mar 2016 18:06:07 GMT

I have one cat who comes in to have his ears clipped by a nurse regularly as he's on a higher dose to help with area for absorption?

RE: Use of Methimazole transdermal gel

Isy Marshall — Wed, 23 Mar 2016 15:25:10 GMT

Brilliant thank you so much for all your advice. I think I will try increasing up to 0.1ml BID and re-check in 3 weeks time. I will have the discussion regarding radioactive iodine treatment or throidectomy but funds may be a bit of an issue.

RE: Use of Methimazole transdermal gel

Harriet Nicholson — Wed, 23 Mar 2016 14:52:41 GMT

We have quite a few cats on this now, we normally start with 0.05ml bid and then increase to 0.07ml bid, then 0.1ml bid if needed, but most have stabilised well.

Rare side effect I realise but we have had a cat diagnosed (yesterday) after 3w transdermal methimazole with likely drug induced hepatopathy. Summit cannot comment as compounder but according to dechra can occur with felimazole so worth checking liver values. Just an anecdote I realise :)

RE: Use of Methimazole transdermal gel

Martin Atkinson — Wed, 23 Mar 2016 13:51:55 GMT

I used it once on a cat with a T4 of >300 and it wasn't even showing signs of hyperthyroidism it was so obese. I found that even with the owner (whose compliance was questionable mind you as she couldn't give tablets) applying as much as she could to both pinna we couldn't get the T4 down as low as your patient's is now! She didn't want a bilateral thyroidectomy because the last one she had done went hypocalcaemic so it went for radio-iodine therapy. The cat is now hypothyroid on supplementation and has renal disease but is still obese. Sometimes you just cant win.

RE: Use of Methimazole transdermal gel

Rob Loxley — Wed, 23 Mar 2016 13:46:15 GMT

Like cats on oral medication, often the dose needed for good control will creep up over time, usually attributed to growth of the goitre. Be aware there is also data that suggests the longer you treat medically the higher the rate of carcinoma becomes.

As for safety/monitoring, I'd go for the same general principles as for methimazole orally. AFAIR the summit stuff is 50mg/ml so you're giving 7.5mg once daily, so room to increase. I'd maybe split the higher total dose twice daily

RE: Use of Methimazole transdermal gel

Richard Carter — Wed, 23 Mar 2016 13:07:26 GMT

think you need to take the thyroid out. Could try increasing but I would have thought it is the same principal of cancer coming out of remission where the target tissue is no longer responding to your medication