Testing for Hyperthyroidism - What do you do

Re: Testing for Hyperthyroidism - What do you do

Martin McDowell — Tue, 11 Mar 2014 12:56:30 GMT

Just to add my penny in here...

The information I have is valid as from mid February. I have asked a few people including a request for advice from Edinburgh Uni and they all advise Summit. The cost is £18 for 3 x 1ml syringes (50mg/ml) and orders under £50 incur a £6 shipping charge. Of curse there is also the practice operating margin. Written prescriptions are not possible on this type of medication.

And just to clarify, this product is NOT a licensed product and is used under the cascade. Summit has received a special license to produce this kind of medication.

http://www.vmd.defra.gov.uk/pdf/register_specials.pdf

Contact details:

Summit veterinary pharmaceuticals limited
26 Chancerygate Business Centre
Langford Lane, Kidlington, Oxfordshire, OX5 1FQ
Tel: 01865 370000

www.svprx.co.uk info@svprx.co.uk

Re: Testing for Hyperthyroidism - What do you do

Michael Woodhouse — Wed, 08 Jan 2014 22:07:24 GMT

[quote user="Martin Atkinson"]£18 for 3 x 1ml syringes, each 0.1ml contains 5mg methimazole (I got that wrong in my previous post) from Summit. They charge postage so you have to factor in that unless you make up a combined order of over £60.[/quote]

Thank you

Re: Testing for Hyperthyroidism - What do you do

Utlendigur — Wed, 08 Jan 2014 20:21:37 GMT

[quote user="Thomas Johnson"]

[quote user="Neil Wheadon"]

Is anyone brave enough to operate on them now, when a number of them go into renal failure and you can't put the thyroid back?

[/quote]

I still do thyroidectomies, though usually only unilateral with a warning to the owner that they may develop disease on the other side, but in my experience that tends to be 18-24 months later. I would always try to stabilise them on medication first, and would expect that to un-mask any renal disease so wouldn't have too many concerns about them going into renal failure after thyroidectomy.

[/quote]

A lot tends to depend on the cat's temperament - some are just too difficult to tablet and/or blood sample, or there may be cost grounds where owners don't want to pay for long term medication and monitoring, or just don't want the hassle.

Re: Testing for Hyperthyroidism - What do you do

Rob Loxley — Wed, 08 Jan 2014 17:59:38 GMT

[quote user="Thomas Johnson"]I still do thyroidectomies

I would always try to stabilise them on medication first, and would expect that to un-mask any renal disease so wouldn't have too many concerns about them going into renal failure after thyroidectomy[/quote]

I'd pretty much echo that - we're still running at a roughly a couple of surgeries a month IIRC, with a few a year going for I-131 (Newmarket AHT is pretty local), the rest staying on longterm medication (have had poor takeup of Y/D). Transdermal medication seems to work well but is pricey - have used it in a couple pre-op.

Re: Testing for Hyperthyroidism - What do you do

Martin Atkinson — Wed, 08 Jan 2014 17:56:04 GMT

[quote user="Michael Woodhouse"]

Gel sounds good, even if just to settle things down pre surgery of the more feisty ones.

May I ask the cost?

[/quote] £18 for 3 x 1ml syringes, each 0.1ml contains 5mg methimazole (I got that wrong in my previous post) from Summit. They charge postage so you have to factor in that unless you make up a combined order of over £60.

Re: Testing for Hyperthyroidism - What do you do

Thomas Johnson — Wed, 08 Jan 2014 17:25:30 GMT

[quote user="Neil Wheadon"]

Is anyone brave enough to operate on them now, when a number of them go into renal failure and you can't put the thyroid back?

[/quote]

Re: Testing for Hyperthyroidism - What do you do

Stephen Courtney — Wed, 08 Jan 2014 17:06:01 GMT

I consider it normal for hyperT4 cats on medical treatment to gradually require higher doses of medication as time goes by - usually over several years.

I don't often send them for surgery, but i do try hard to get owners to consider I 131 therapy. My success rate at this is pretty low, even though it takes about 18-24 months to be financially ahead on I 131. the quarantine period puts people off, and frankly so do the immediate costs, but even insured clients usually balk. If anyone has any client management tips I'm listening...

The other thing to remember is that with both surgery and radio iodine, the condition can recur, as new adenomas can form.

Re: Testing for Hyperthyroidism - What do you do

Neil Wheadon — Wed, 08 Jan 2014 17:02:53 GMT

Is anyone brave enough to operate on them now, when a number of them go into renal failure and you can't put the thyroid back?

Neil

Re: Testing for Hyperthyroidism - What do you do

Michael Woodhouse — Wed, 08 Jan 2014 16:58:57 GMT

Gel sounds good, even if just to settle things down pre surgery of the more feisty ones.

May I ask the cost?

Re: Testing for Hyperthyroidism - What do you do

Martin Atkinson — Wed, 08 Jan 2014 16:41:08 GMT

[quote user="robloxley"]My understanding was that the thyroid adenoma continued slowly to grow over time[/quote]Given that the vast majority of hyperthyroidism in cats is benign hypertrophy I don't think this is particularly relevant. I actually find the opposite - that the dosage requirement of Felimazole decreases. Maybe my clients are better at complying with treatment or maybe as most of the patients are knackered old cats their non-thyroid disease is decreasing their metabolic rate and the production of thyroid hormone reducing correspondingly.

Incidentally I have my first cat on methimazole transdermal gel. Pre-treatment T4 >307nmol/l. Owner incapable of pilling, cat won't eat anything other than favourite food, doesn't want surgery, can't afford radio-iodine therapy. After first 3 weeks of 0.1ml gel (2,5mg methimazole) on underside of pinna bid the T4 has come down to 193. We'll double the dose and re-test in another 3 weeks. Sounds like may be an expensive option but I'll keep you all posted on progress.

Re: Testing for Hyperthyroidism - What do you do

Rob Loxley — Wed, 08 Jan 2014 16:25:51 GMT

[quote user="KathW"]cats diagnosed with hyperthyroidism tend to become steadily worse over months to years - needing higher and higher tablets doses[/quote]

My understanding was that the thyroid adenoma continued slowly to grow over time, and the drug dose was more related to the size of the adenoma that just the cat, hence the dose creep?

Re: Testing for Hyperthyroidism - What do you do

KathW — Wed, 08 Jan 2014 15:34:43 GMT

That's a good point Thanks Neil. Perhaps the owners also become more lax about giving the tablets as time goes on. I've certainly had some when this has been the case- with closer questioning.

Re: Testing for Hyperthyroidism - What do you do

Neil Wheadon — Wed, 08 Jan 2014 15:20:21 GMT

[quote user="KathW"]Does any one else feel that more cats diagnosed with hyperthyroidism tend to become steadily worse over months to years - needing higher and higher tablets doses[/quote]

I had one of these last month and MSD have a really helpful advise line (Vidalta)

What I did learn was that bioavailability of the drug increased by 30% if given with food.

Talking to the owner he said that initially as the cat was so hungry giving with food wasn't an issue. As time went on the cat returned to its normal way, so I wonder if the bioavailability decreases in part due to this.

Neil

Re: Testing for Hyperthyroidism - What do you do

KathW — Wed, 08 Jan 2014 15:08:29 GMT

Does any one else feel that more cats diagnosed with hyperthyroidism tend to become steadily worse over months to years - needing higher and higher tablets doses (? No data just a feeling that 10+ years ago we stabilized them on tablets ( if we didn't operate) and they tended to stay fairly well controlled.

Re: Testing for Hyperthyroidism - What do you do

Martin Atkinson — Wed, 08 Jan 2014 14:13:58 GMT

I cannot remember a single cat that I've not been able to diagnose with hyperthyroidism with a combination of TT4, raised ALT/P and clinical signs. No I lie - there was one I confirmed with Idexx's feline specific T4 which was stubbornly at the op end of normal for T4 when the top end of normal range was about 60, now it is widely recognised as 40 they all fit the basic lab results.

But like Michael most of the new cases I'm diagnosing are well into the hundreds, one was >307 (Axiom's maximum readable) and showed barely any signs of classical hyperthyroidism. Is there something else going on here that we're all missing?

Re: Testing for Hyperthyroidism - What do you do

Michael Woodhouse — Wed, 08 Jan 2014 13:48:44 GMT

I'm doing less smallies but I struggle to think of a cat newly diagnosed with a T4 less than 100, they are usually good and high.

I think if you restrict your testing to likely candidates (ie confirming a clinical suspicion, working up wt loss) then the standard laboratory test seems to pick them up the right candidates. If we get an equivocal result we will re test in 4-6 weeks.

If you go 'fishing' then I suspect you'll find a lot more cases where the T4 is just a bit out of the reference range.......

(We use Cambridge lands for odd things, but they tend to be expensive and there is obviously added cost sending the sample to two labs. Idexx have a very good value 'thin cat' profile including a T4 for little money. Lots of uninsured clients)