South African Equine Veterinary Association Congress 2015 Protea Hotel Stellenbosch
concentration to suppress (<1.0 μg/dl) 19 h after dexamethasone administration (40 μg/kg, IM).
Treatment with pergolide mesylate (2 μg/kg, PO, q 24 h) was started within 7 days of initial
evaluation. Animals were re-evaluated (clinical exam and endocrine testing) after 90 (n=113) and
180 days (n=111) of treatment. When endocrine test results remained abnormal at 90 days (n=47),
the dose was increased to 4 μg/kg, PO, q 24 h. Treatment success after 180 days was defined as
either normalization of dexamethasone suppression test results (<1.0 ug/dl) or a decrease in
plasma ACTH concentration by 50% (or to <50 pg/ml when initial value was <100 pg/ml) and
improvement by a score of >1 in at least one clinical sign. Treatment was also considered
successful when the sum of clinical scores decreased by >3, regardless of endocrine test results.
Treatment compliance and minor adverse events were reported by reviewing daily written entries
in a standardized diary at 90 and 180 day evaluations. Adverse events requiring veterinary
evaluation during interim periods were reported to study investigators within 24 h and further
investigated to determine seriousness.
In all, 76% (86/113) equids were classified as treatment successes (two horses withdrawn by their
owners between 90 and 180 days were categorized treatment failures). The remaining nine
animals died (n=8) or were euthanized (n=1) due to worsening of pre-existing conditions
(laminitis and dental disorders) or colic. After 90 days of treatment, 58% (66/1