Evaluating an Adjunct Therapy for Cushing’s Disease

More than 20% of older horses suffer from pituitary pars intermedia dysfunction (PPID). Also known as Cushing’s disease, PPID is caused by inappropriately high circulating hormone levels. Affected horses are more likely to develop foot disease and bacterial infections and show dullness and poor performance. Many equine patients that develop complications are euthanized. The treatment of choice for these patients is a drug called pergolide. However, this drug is relatively expensive and as a horse ages, the disease gets worse, prompting the need for higher doses to manage symptoms and for some, more complications. In this project, researchers will investigate if adding a more cost-effective drug called cyproheptadine improves clinical response. Cyproheptadine has been given to horses for decades but scientific data about its effectiveness is lacking. If results show that combination treatment helps horses with PPID, the team will have paved the way for a less expensive way of helping older horses with PPID and provided a science-based recommendation for horses that do not tolerate pergolide well and are in desperate need for another treatment path to remain healthy.