PPID and compliance

Host

Welcome to the Bova UK Podcast, where we discuss diseases from diagnosis through to management. These podcasts are aimed at registered vets and veterinary nurses. If you’re listening as a pet owner, please consult with your local veterinary surgeon if you have any concerns about your animal.

Today I have with me Dr. Nicola Menzies-Gow, lecturer in equine medicine at the Royal Veterinary College. She is also an RCVS and European internal medicine specialist with a special interest in endocrine disease, including PPID and compliance in horses. Welcome, Nicola! How are you?

Dr. Nicola Menzies-Gow

I’m good, thank you. How are you?

Host

Very well, thank you – although it’s a bit windy today! So, Nicola, can you tell us a bit more about how your interest in endocrine disease developed?

Dr. Nicola Menzies-Gow

Sure! My interest began during my residency when I was given a project on endotoxemia and laminitis in post-op colic patients. That research expanded into a PhD and gradually evolved from endotoxemia to laminitis, and then into endocrine-related laminitis and diseases like EMS and PPID.

Host

Very relevant for today’s discussion! We’re focusing on PPID and compliance. What should we really be aiming for when treating PPID?

Dr. Nicola Menzies-Gow

Ultimately, we want owners to give the treatment as prescribed—say, one tablet daily—and follow up appropriately. But in reality, compliance isn’t perfect. Owners forget, make adjustments, or may not be able to follow the plan. As vets, we often assume the medication has been given correctly when a patient isn’t improving, but we need to consider compliance first.

Host

I think many of us are guilty of forgetting medication! Is pergolide always necessary for PPID cases?

Dr. Nicola Menzies-Gow

Not necessarily. It depends on the horse, the clinical signs, and the owner’s circumstances. If the signs are mild or the owner can’t commit to lifelong treatment or regular monitoring, pergolide may not be the best option. It’s about balancing what’s best for the horse and what’s practical for the owner.

Host

So where does ACTH testing fit in? How important is it?

Dr. Nicola Menzies-Gow

ACTH is useful but not perfect—about 80% sensitivity and specificity. That means one in five times it might give an incorrect result. It’s better now with seasonally adjusted reference ranges. I believe ACTH should be interpreted alongside clinical signs, not in isolation.

Host

And what about insulin concentrations—should we be monitoring those too?

Dr. Nicola Menzies-Gow

Absolutely. Insulin dysregulation is often what drives laminitis in PPID cases. If it’s present, it signals a worse prognosis. You’ll want to monitor and manage that alongside the PPID, potentially with dietary changes or exercise if appropriate.

Host

Does pergolide directly lower insulin levels?

Dr. Nicola Menzies-Gow

Not directly. The hope is that by controlling PPID with pergolide, the insulin levels will come down indirectly.

Host

Some people wonder whether we’re over-diagnosing PPID and overlooking EMS. Is that a fair concern?

Dr. Nicola Menzies-Gow

It’s complex. Some horses start with EMS and later develop PPID. Others may have insulin dysregulation because of PPID alone. Both conditions can overlap, and insulin seems to be the key driver of laminitis either way. The cause isn’t fully understood.

Host

Why do some horses respond only partially to pergolide?

Dr. Nicola Menzies-Gow

There are many reasons. First, check if the horse is actually receiving the drug. Partial response could also be due to the nature of the disease—some conditions only respond partially to management, not just pergolide.

Host

What about Shetlands and older horses? Why is compliance often poor?

Dr. Nicola Menzies-Gow

Shetlands can be tricky—small doses, hard-to-split tablets, and clever ponies! Older horses often receive less attention or are retired, so owners may be less consistent or less willing to invest in long-term treatment.

Host

Would easier formulations, like a pergolide paste, improve compliance?

Dr. Nicola Menzies-Gow

Definitely. If it’s palatable and easier to administer, owners are more likely to comply. Syringes with weight-based markings make titration simpler too, especially for smaller ponies.

Host

We’ve also heard about cabergoline injections being used weekly in the US and Australia. Do you think that’s about effectiveness or compliance?

Dr. Nicola Menzies-Gow

Likely both. If proven equally effective and long-lasting, a once-weekly injection could be a game-changer. But we need more evidence on how long it maintains therapeutic levels and whether it matches pergolide in efficacy.

Host

Would you say cabergoline could be a viable option in future?

Dr. Nicola Menzies-Gow

Yes, especially if we get data showing comparable results. But we need to be cautious and ensure it’s tested in appropriate patient groups—not just those who failed pergolide, as that might skew perceptions of efficacy.

Host

And finally, any take-home messages?

Dr. Nicola Menzies-Gow

Yes—before adjusting the dose or switching drugs, check compliance. Open a supportive dialogue with the owner. They may be struggling with administration or costs. There are creative ways to help—using treats, pastes, or syringes—and involving owners in problem-solving helps ensure better outcomes.

Host

That’s a great reminder. Thank you so much, Nicola. That’s been incredibly insightful.

Dr. Nicola Menzies-Gow

Thank you for having me!

Host (Outro)

These podcasts aim for registered vets and veterinary nurses. If you’re listening as a pet owner, we always advise consulting your local veterinary surgeon if you have any concerns about your animal.