Re: Questions about Metformin

Kirsten Rasmussen

Hi Angela,

So you started soaking hay and started Metformin together before your last test result.  That means it could be the hay soaking that helped and not the Metformin.  For retesting, I'd say every 3 months is nice if you can manage that, or sooner if you see a change in hoof comfort.

I'm surprised her insulin is still so high on that low sugar hay. Getting her weight down might help but usually it takes more than that.  I can think of 3 options.  Maybe others will have better feedback...

1. If/when she is sound get her exercising, a lot.  You want her heart rate elevated for 30 min so it's a real workout, at least 5 days a week.  This means cantering on a lunge line, riding at a fast trot or canter, doing hill work, etc.  Even if you can get her lunging at a fast trot for 30 min a few times a week, that should help.  But only if she's sound.

2.  Try increasing her pergolide.  It could be that her ACTH is not reflective of the degree of her PPID since we know there are other hormones involved that increase insulin.  Does she have physical signs of PPID that worsen in the fall?  Topline loss, polyuria/polydypsia, soft tissue injuries, abscesses, skin issues, etc.  Onset of hoof pain in in late summer to fall with no other management changes is another indicator of uncontrolled PPID.  These might justify a higher pergolide dose even if her ACTH looks good.

3.  Consider Invokana.  If you cannot get her insulin below about 40 uIU/mL with hay soaking, low sugar hay and Metformin (and lots of exercise if she's able), you could ask your vet to email drkellon 'at 'gmail 'dot' com to get some information on the feeding and testing protocols she advises for trying Invokana.

Kirsten and Shaku (IR + PPID) - 2019
Kitimat, BC, Canada
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