Vetoryl no longer working

[cate]

Cate our now 10yr old border collie was diagnosed with Cushings in Nov 2019 at UT Vet School. She was started on 40mg of Vetoryl. With in 3 days the excessive drinking and peeing was eliminated. She had lost a lot of fur and they had shaved her belly but within 6mos her fur had grown back and things were great. She started playing again etc. In June of 2020 I thought maybe we could back off a bit on the Vetoryl to 30mg (less drug better right) but my Oct2020 I realized that her water consumption was increasing and her fur was looking rather unhealthy. So after a cortisol check which was 2.9 we went back to 40mg a day. By December 2020 still no real improvement. Cortisol at 3.3. We have been inching up on Vetoryl. 12/3/20 45mg, 12/17/20 50mg. 1/12/21 55mg and 1/19/21 60mg.
Tested cortisol 2/2/2021 Cortisol3.5. Vet is doing the prevetoryl check to hold the cost down.
Question 1 does Vetoryl just stop working?
Question 2 Weighing 44# then 60mg is a middle of the road dosage. Continue to increase dosage?
Question 3 Other than her excessive drinking 120 oz/day water and peeing(amazing no accidents), some fur loss,
Cate has no other obvious signs blood pressure normal electrolytes normal, energy level (walks 4-6miles/day) .
Change to Lysodren??
Any comments would be appreciated.

ACTH at dx 29.5ug/dL

[LauraA]

Just wanted to share my experiences with the PVC test. When I was doing it it was showing at the lower end of normal for my Cush girl. However her drinking and hunger were getting worse and so a week after we did the latest PVC test we did the ACTH Stim test. The Stim test showed that her cortisol was actually very high - I think it was around 155nmol. She was usually around 90-100 nmol which is where she liked to be. It may be worth getting an ACTH Stim test and seeing what that result is. I am assuming a full blood panel has be done to look at kidney function and a urinalysis to check for UTI, glucose in urine and specific gravity.

[cate]

Thanks and the vet recommends we go back to UT for consult. Of course they will probably run all tests again to a tune of $1600.
Even if her cortisol is higher the question still is why is the Vetoryl is not working anymore and upping the dosage isn't showing any improvement in symptoms(120oz + water and urinating a lot.)
Kidney function good, UTI no indication in catch sample, No glucose, Specific gravity very dilute. Electrolytes normal, blood pressure good.
We are upping dosage to 70mg(split am/pm) of Vetoryl with fingers crossed today. It is a lot of pills when we only have 10 & 5mg pills.
We get Vetoryl from Walmart petrx. Any concerns???

[labblab]

Hello to you and Cate! I’m soooooo glad that Laura has had the chance to greet you and to share her thoughts, and I’ll be writing more myself later on today or tomorrow — unfortunately this has just turned out to be a busy day for me. But I’m so glad you’ve joined us, and I’ll be adding a proper reply as soon as I can.

In the meantime, welcome!
Marianne

[LauraA]

It is common for dogs to have to have the dose increased/decreased over time. My girl was pretty stable for about 5 years and then we had to increase her meds about 3 times in a few months. I know that I always got a urine culture done as the dipstick method usually done at the vets didn't show up the bacteria in a UTI since the urine was so dilute. I have seen some small dogs on some pretty hefty doses of Vetoryl so I wouldn't be too worried about 70mg. Can you not get the the 30mg Vetoryl or the compounded version called Trilostane (so much cheaper than Vetoryl). If you got Trilostane you could get 35mg tablets if doing a split dose (for a total of 70mg a day). I imagine getting 10mg and 5mg is VERY expensive.

[cate]

Yes! Everything about this disease is expensive but until we can see Cate respond to a dosage then we will order in cheaper quantities.
Question ! I have been reluctant to do the UTI culture for various reasons(no peeing urgency even with the amount of water she is drinking, no obvious pain or discomfort, no licking or concern by Cate to that area) but...
Would a UTI result in elevated cortisol readings.???
If yes I will have them culture immediately.