Cadet update--is Invokana losing its effectiveness?



Cadet's case history is up to date, including Cornell numbers from 12/7/23.

I've been struggling with him not eating his meals, in spite of an excellent appetite for hay, and I'm afraid I've gotten tunnel vision and missed another problem developing that I've only clued into today.  Since having a program to balance his minerals, thanks to Dr. Gustafson, I have been having trouble getting Cadet to eat the extra Cu and Zn in his meals, but around mid November he started to refuse meals containing Ca Trace Plus too.  Over the next couple of months, I deconstructed his meals, tried switching to Vermont Pro Plus, and tried the CTP as a powder instead of pellets, introducing each gradually.  I also tried many of the suggestions on the Picky Eaters checklist, including alfalfa tea, distillers' grains, changing the flavor of Stabul 1, alternative safe feeds, CocoSoya oil, and ground up Stabul treats.  I have yet to be able to get him to eat more than half of the CTP that he needs and have given up on the extra Cu and Zn.  His willingness to eat meals has remained very unpredictable and he always prefers hay to his meals.  On 1/12/23, I started Cadet on omeprazole (1 full tube of Ulcergard QD) to see if this improved his appetite for meals.  On 1/16/23, I ran a CBC and profile, which was WNL except for a barely elevated GGT of 39 U/L (9-37 U/L); triglycerides were 55 mg/dL (10-90 mg/dL).  There was no real change in his willingness to eat meals after 6 days of omeprazole.

I knew he had gained some weight this winter, but was shocked today at his calculated weight of 1150 lbs.  He doesn't have bulges above his eyes or a crest, but fat is evident over his ribs and behind his shoulder.  I also checked his urine today (6.5 hours after receiving Invokana) and it showed glucose of 250-500 mg/dL.  He has always showed 500 mg/dL before.  Combined with an increase in his insulin to 46.88 uIU/mL (10-40 uIU/mL) in mid December, I wonder if the Invokana is losing its effectiveness.  He's been on 300 mg QD since October of 2022.  The medication is kept at room temperature and I give it to him myself by hand.

He has hay available free choice, as indicated for horses on SGLT2i, and I wonder if the problem with his meals is that he is just not hungry enough for something that doesn't taste as good as hay.  I've been tempted to muzzle him for several hours, which would pretty much prevent his eating hay, and then offering the meal.  This might facilitate weight loss too, but I don't want to cause a problem by fasting him on the Invokana.  If this is even safe to do, how long would be reasonable?  Should I consider switching him to Steglatro?  What would his dosage be?

On a more positive note, he has been sound without boots and I am trying to exercise him, including riding him on trails at a walk, as much as the weather allows.  I really hope I haven't caused him harm by not monitoring his weight more closely.  Thank you in advance for any advice!

October 2018
Island County, Washington, USA
Cadet Case History:
Ruger Case History:

Cadet Photo Album:

Join { to automatically receive all group messages.