Treatment with Pergolide or Cyproheptadine of Pituitary Pars Intermedia Dysfunction (Equine Cushing’s Disease)

Abstract

Medical records of 27 horses (including 13 ponies) treated with pergolide or cyproheptadine for pituitary pars intermedia dysfunction were reviewed to determine the effect of treatment on plasma ACTH, insulin, and glucose concentrations and clinical signs. Prior to treatment, the most common clinical signs were laminitis, hirsutism, and abnormal body fat distribution. The median pergolide dose was 3.0 microg/kg p.o. q24h (range, 1.7-5.5 microg/kg). All horses treated with cyproheptadine were given 0.25 mg/kg p.o. q24h. After pergolide treatment, ACTH concentrations (n = 20; median = 30.4 pg/ml; range, 4.2-173) were significantly lower (P < .01) than those in horses treated with cyproheptadine (n = 7; median = 141.0 pg/ml: range, 10-1,230). Among horses treated with pergolide, there was a correlation between ACTH concentration after treatment and the duration of treatment (P < .001) and pergolide dose (P = .04). Significantly (P = .02) more owners of horses treated with pergolide (85%, 17/20) reported an improvement in clinical signs compared to owners of horses treated with cyproheptadine (28%, 2/7).

Effects of season and sample handling on measurement of plasma α-melanocyte-stimulating hormone concentrations in horses and ponies

“…[13][14][15][16] For Siberian hamsters and short-tailed weasels, a-MSH concentration is reported to increase during the summer, at a time when coat changes color. 3,18,19 Development of a winter coat also begins as length of day decreases in the fall. 13 In Soay sheep, a feral breed of sheep in Scotland, plasma concentration of a-MSH is greatest in late summer and fall.…”

“…Despite recognition of this condition for more than 70 years, the cause and pathogenesis of PPID remain poorly defined. 3,4 In horses with early disease, the clinical signs often overlap with phenotypic changes observed with normal aging. In aged horses with advanced disease, the presence of clinical signs, including hirsutism, laminitis, muscle atrophy, abnormal fat distribution, polydipsia and polyuria, hyperhidrosis, and secondary infections, may be sufficient for diagnosis.…”

Seasonal Changes in Circadian Peripheral Plasma Concentrations of Melatonin, Serotonin, Dopamine and Cortisol in Aged Horses with Cushing’s Disease under Natural Photoperiod

“…Currently, the aetiology, pathogenesis and treatment of PPID and Cushing’s syndrome are a matter of intense debate and there is no reliable prophylaxis, or remedy, for the disease (2). Treatments are generally given to ameliorate the clinical signs and may include dopamine agonists, serotonin (5‐hydroxytryptamine/5‐HT) antagonists (6, 7) and/or nonsteroidal anti‐inflammatory drugs and blood vessel dilators where laminitis has developed (4). The administration of dopamine and its agonists was reported to decrease plasma concentrations of pro‐opiomelanocortin (POMC)‐derived peptides (8).…”

Dermatographism in a horse, responsive to cetirizine treatment

“…In horses, some reports are available on the use of cyproheptadine in cases of pituitary pars intermedia dysfunction (Donaldson et al . ) and headshaking (Madigan et al . ).…”