How long does One-Alpha take to kick in for hypocalcemic cat post-thyroidectomy?

RE: How long does One-Alpha take to kick in for hypocalcemic cat post-thyroidectomy?

Beats — Sun, 24 Sep 2023 21:25:37 GMT

Thanks Kate!

There is also a little cholecalciferol (VitD3) in these calcium carbonate tablets - only 2.5mcg per tablet I think from memory, so perhaps not likely to make much difference, but I can't figure out where cholecalciferol fits into all this - I think it is not activated in the absence of PTH perhaps, but am not 100% clear on that?

Is it possible that one-alpha (alfacalcidol) does not get activated either in the absence of PTH or due to cats (all or some) not hydroxylating it in their livers the way people do? Has anyone ever had success with alfacalcidol in a cat before? (I've used it in dogs post parathyroidectomy removal with apparent success, but this is my first time trying in a cat - oit sounded an attactive option being a very low volume, inexpensive, basically the same as calcitriol with automatic liver-hydroxylation, and once daily dosing in BSAVA formulary, but the evidence before me would be that it doesn't actually appear to work)

Has been getting 0.2ml of the one-alpha daily by mouth for enough time (incluing alongside plenty of oral calcium now) that I should think its effect would be seen if was doing anything much - the ionised calcium is still in the 0.5 to 0.6 range...

On the plus side the cat is eating well and these meds can now be given in food, which would pave the way to the cat going home if only they appeared to be doing something and I didn't think it would seizure if sent home - I'm uncomforatble with going home with an ionised calcium below 0.8, but I might just have to accept that and give owner some injectable CaGluconate for if seizures. I have stopped giving injectable calcium gluconate from last night and am planning on monitoring on signs only at this point as cat is doing well and apparently better adapted to its low blood calcium than it was a week or more ago.

I wondered about getting the rocaltrol capsules and giving twice daily, but then in some sense I am starting another fresh experiment on dosing with more monitoring required perhaps. Also I have only ever used the TEVA calcitriol tabs in dogs and am not familiar with the rocaltrol capsules - can you advise what in your experience has practically worked for a cat like this in the past using the rocaltrol capsules?

Is low Mg post-thyroidectomy in a cat as cause of persistent hypocalcemia a recognised thing or more as a general point low Mg causes hypocalcemia not responsive to calcium supplmeentation in any species? How would I best supplemment magnesium in a cat and is it safe to just do this without testing if this is a likely cause?

I really appreciate your generosity in taking the time to sharing your experience with me - many thanks once again!

RE: How long does One-Alpha take to kick in for hypocalcemic cat post-thyroidectomy?

Kate Murphy — Sun, 24 Sep 2023 13:44:37 GMT

Hi Beats

For calcium dosing my references are

Calcium supplements
- Calcium carbonate/gluconate/lactate dose at 25-50mg/kg day elemental calcium- give divided as 2-3 times daily
- 1mg elemental calcium =
  - 11.2mg calcium gluconate e.g. 600mg calcium gluconate tablet contains 53.4 mg elemental calcium
  - 7.7mg calcium lactate
  - 2.5mg calcium carbonate e.g. 1250mg Calcichew contains 500mg elemental calcium
  - Eg 10kg dog needs 250-500mg elemental calcium/day divided into eg twice daily so ½ Calcichew twice daily
  - These can be withdrawn if calcium is remaining high normal or above reference interval
- So I think with your 0.5 x 400mg calcium carbonate tablet you will be giving 80mg elemental calcium and you are giving it 2-3 x day ie 160-240mg total dose and our aim is 25-50mg/kg/day elemental calcium as divided doses (100-200mg total daily dose- so you are giving adequate amount).
- Persistent hypocalcaemia despite supplementation with Ca/Vit D can reflect hypomagnesaemia so it is worthwhile checking magnesium in blood in these cases.
Hope this helps
Kate

RE: How long does One-Alpha take to kick in for hypocalcemic cat post-thyroidectomy?

Beats — Sat, 23 Sep 2023 15:56:18 GMT

have started on half a 400mg calcium carbonate tablet ("valupak" brand Valupak Chewable Calcium & Vitamin D Tablets 30's - Vitamins & Supplements from Chemist Connect UK) 2-3 times daily alongside the 0.2ml one-alpha once daily over the weekend to see if that maintains the calcium at an acceptable level by Monday without need for further injections. This seems like big oral doses, but as the ionised calcium was still between 0.5 and 0.6 this morning (prior to caGluc injection and starting this oral dosing) i don't think likely I will overdose. It is possible that I am only measuring ionised calcium at its lowest point (eg first thing in morning and then level goes up really high shortly after dosing and then drops again. Perhaps I will try a 1st thing monday mroning sample and then a again 2-4 hours after dosing with oral calcium and one-alpha and see if there is a difference.

have been able to tablet, with some difficulty, today. I don't think the owner could do this at home, and I'm not sure I could on more than short-term basis but will see how I get on as would prefer to be on oral plan than injections if possible.

RE: How long does One-Alpha take to kick in for hypocalcemic cat post-thyroidectomy?

Beats — Fri, 22 Sep 2023 09:43:16 GMT

I suspect there is not enough calcium in the Collo-Cal D. It doesn't actually say how much is in it - just lists ingerdients to include calcium chloride (but internet would suggest a very low amount). I ahve sent a request to Allflex/MSD to clarify, but probably better to use an alternate product.

Had tried this because was liquid. I guess I could try pouring some of the injectable calcium gluconate 10% over chicken, but any other suggestions of specicif products gratefully received. (liquid in preference to tablets - I can inject the cat easily, but giving tablets likely to be tricky even for me - squirting meds in mouth hard enough).

I'd hoped the alfacalcidol alone would have sufficed but I guess I underestimated the importance of provided excessive dietary calcium at same time?

EDIT: very quick response from company:

Ingredients:Colloidal calcium oleate 0.75% w/v, Vitamin D 70 i.u/ml

Further information:Elemental CA/ml –approx 0.52mg/mlVIT D compound D2

RE: How long does One-Alpha take to kick in for hypocalcemic cat post-thyroidectomy?

Kate Murphy — Thu, 21 Sep 2023 21:06:00 GMT

Ok disclaimer….not had much sleep thanks to very delayed flight home last night so I will need to revisit dosing with fresh brain tomorrow. One alpha needs hepatic conversion but you would expect response within the time scale you mentioned,

One-Alpha 2mcg/ml solution [0.1ml =0.2mcg; 0.05ml = 0.1mcg]
- Reading the SPC for One-alpha
  - 1 drop of One-Alpha = 0.1microgram (100 nanogram) and dose is from BSAVA formulary for alfacalcidol is 0.01-0.03mcg/kg daily and titrated to effect

I tend to prefer using rocaltrol as works faster but in small patients you need to aspirate liquid from capsule to dose so can be less accurate

with the oral,calcium we need to,look at elemental calcium content so maybe you can share the detail on the product you have
hope that helps for now

best wishes Kate

RE: How long does One-Alpha take to kick in for hypocalcemic cat post-thyroidectomy?

Alasdair Hotston Moore — Thu, 21 Sep 2023 08:40:07 GMT

Kate Murphycan you help with this one?