Drug for Cushing's disease approved

The Food and Drug Administration announced Nov. 17, 2011, that it has approved the first drug for the treatment of pituitary pars intermedia dysfunction (Cushing's disease) in horses. PPID is a common disease of older horses that results in substantial morbidity and death if left untreated.

Administered in tablet form, Prascend (pergolide mesylate) is intended to control clinical signs associated with the disease.

Pergolide mesylate is a dopamine agonist that is believed to work by stimulating dopamine receptors in horses with PPID. It has been shown to decrease plasma concentrations of adrenocorticotropic hormone, melanocyte-stimulating hormone, and other pro-opiomelanocortin peptides.

PPID usually affects horses in their middle to late years of life. Signs of the disease include a long, curly coat that does not shed properly, excessive water drinking and urination, abnormal fat distribution, muscle loss, excessive sweating, general malaise, chronic laminitis, and a compromised immune system, which can lead to respiratory ailments, skin infections, hoof abscesses, and tooth infections.

This is the third drug recently approved by the FDA that was previously available only through compounding from bulk substances. Proin and Incurin, both intended to control urinary incontinence in dogs, were approved this past July.

Prior to Prascend's approval, equine practitioners often used pergolide in compounded form to treat horses with PPID; however, now that there is an FDA-approved product, compounding pharmacies will no longer be able to compound from the bulk product.

A spokesperson for Boehringer Ingelheim Vetmedica Inc., the drug's manufacturer, said the price to veterinarians is $82 for a 60-count bottle and $200 for a 160-count bottle.