Effects of Pergolide Mesylate on Plasma Adrenocorticotropic Hormone Concentration in Horses With Pituitary Pars Intermedia Dysfunction

Aims: Pituitary pars intermedia dysfunction (PPID) is a common degenerative neuropathy of horses associated with ageing. Pergolide mesylate (pergolide) is the only licensed treatment for PPID in the UK; however, published evidence of its efficacy is limited to small case series and anecdotal reports. This study evaluated adrenocorticotropic hormone (ACTH) responses in horses treated with pergolide and investigated factors that may influence response to treatment. 

Methods: A retrospective review of submissions to The Liphook Equine Hospital Laboratory was performed from January 2007 to December 2012 and cases in which ACTH concentration was measured before and after instigation of pergolide treatment were identified. Data were analysed using Rv.2.15 software (R Development Core Team). Improvement was defined as a reduction of ACTH concentration of ≥75%, or a return of ACTH concentration to within seasonally adjusted reference intervals. [...]