Veterinarians use a lot of human medications to treat animals. The cold, hard reality is that there is more money in developing meds for people, so vets are often left looking at what’s available in the human sphere and trying to figure out what may or may not be useful in animals.
In most cases, this situation works pretty well, but when a human drug is pulled from the market, the fact that veterinarians have come to rely on it is usually not enough to keep it in production. This was the case when in 2007 the medication pergolide, which had been used to treat Parkinson’s disease in people, was withdrawn from the U.S. market because it was linked to problems with patients’ heart valves. Unfortunately, pergolide was also the go to treatment for a condition in horses called Pituitary Pars Intermedia Dysfunction (PPID), or Cushing’s disease.
The symptoms of PPID in horses include a long, curly coat that doesn’t shed normally, increased thirst and urination, muscle wasting, abnormal fat distribution, excessive sweating, lethargy, laminitis, and recurrent infections. Most animals are middle aged or older when they are diagnosed. Pergolide certainly isn’t a miracle cure for PPID. Affected horses have to receive the medication for the rest of their lives, and the costs do add up, but it is the best tool we have for controlling their symptoms.
When human pergolide was discontinued, horse owners were forced to turn to compounding pharmacies. Compounding pharmacies had been making pergolide from bulk materials even when the Food and Drug Administration (FDA) approved human product was available, but previously owners could choose which option was right for their situation.
Compounding pharmacies usually do a good job, but their products do not receive oversight from the FDA. Mistakes have been made in the formulation of compounded products (remember the 21 polo ponies that died in 2009), and they often do not have the shelf life and consistent drug delivery of FDA approved medications.
If you have a horse with PPID, I have some good news for you. Prascend, a new veterinary, FDA approved version of pergolide is now available. I strongly recommend you talk to your veterinarian about whether or not Prascend is a good choice for your horse. It looks like Prascend is more expensive than compounded pergolide (at least for now; I’ve seen prices drop precipitously on newly released FDA approved veterinary products in the past), but the benefits of safety, consistency and stability are certainly worth something.
Pet owners and veterinarians also need to support drug manufacturers that are willing to get FDA approval for their products. If we don’t, there may not be many left to choose from.
Dr. Jennifer Coates