Pergolide mesylate is initiated at 2 μg/kg PO q24h and monitored with basal plasma adrenocorticotropic hormone (ACTH) measurement at 4–6 week intervals until clinical signs and/or endocrine results stabilize or improve. The Veterinary…
The starting dose is 2 μg/kg PO q24h, which is the licensed dose in both the UK (Prascend, Boehringer Ingelheim) and the US.The Veterinary…+1 A dose of 4 μg/kg PO q24h has also been used in long-term treatment, with 7 of 13 horses on the lower dose requiring escalation to 4 μg/kg PO q24h between 1.7 and 4.7 years into treatment.Journal of Vete… Importantly, not all horses require progressive dose increases — some respond favorably to the initial dose long-term.Journal of Vete…
Plasma ACTH begins to fall within 12 hours of the first dose, with further reductions occurring over the first 10 days of treatment.Domestic Animal… Alterations in the thyrotropin-releasing hormone (TRH) stimulation response are detectable by day 8, with no further change identified at day 18.Domestic Animal… Despite this rapid onset, the Prascend datasheet recommends repeating endocrinologic testing every 4–6 weeks until stabilization.The Veterinary…
After 5.5 years of treatment, owners of 13 surviving horses reported sustained clinical improvement, and endocrine test results normalized in 75% of those animals. After 9.5 years, only 2 of 6 surviving horses maintained normal endocrine test results, reflecting the progressive nature of the disease.Journal of Vete… Median survival time from enrollment was 3.6 years (range 0.6–10.5 years), with 5 horses euthanized specifically for chronic laminitis.Journal of Vete…
Monitoring in practice is frequently inadequate. Only 76% of pergolide-treated, PPID-positive horses had any recorded monitoring, and fewer than half of those monitored (48.1%) had follow-up basal ACTH testing within the recommended 1–3 months of diagnosis.The Veterinary… Repeating basal ACTH at 1 month after treatment initiation has been proposed as a means of identifying false-positive results at initial testing.The Veterinary…
Twice-daily dosing may reduce ACTH fluctuation. Pergolide has a terminal elimination half-life of less than 12 hours, and median plasma peak concentrations are more than four times higher than median trough concentrations after once-daily dosing.Domestic Animal… Plasma ACTH fluctuates in parallel with pergolide concentration, which supports a pharmacokinetic rationale for q12h dosing to reduce ACTH variability, though the licensed regimen remains q24h.Domestic Animal…
Adverse effects are primarily gastrointestinal. Inappetence is the most clinically relevant adverse effect; the Prascend datasheet recommends a reduced dose for a short period in affected horses before re-escalating.The Veterinary… Pergolide inhibits prolactin release and should be used with caution in lactating mares.FDA DailyMed An… Valvular fibrosis is a recognized concern with dopamine agonists in humans, but echocardiographic evaluation of horses on pergolide found no valvular regurgitation and no differences in left ventricular systolic or diastolic function between treated and untreated PPID horses.Journal of Vete…
Pergolide treatment improves fasting insulin and promotes weight loss — pergolide-treated horses lost weight and had improved fasting insulin compared to placebo-treated horses, which gained weight and rump fat thickness over 12 weeks.Domestic Animal… In horses with concurrent PPID and insulin dysregulation (ID), pergolide also reduces postprandial hyperinsulinemia, though it does not improve tissue insulin sensitivity as measured by intravenous testing methods.Equine Veterina… Horses with PPID alone (without concurrent ID) showed no insulin benefit from pergolide.Equine Veterina…
Pergolide does not appear to restore immune function despite normalizing ACTH. PPID horses have altered systemic immune function including reduced interferon-γ production and increased IL-8 expression, but pergolide treatment does not correct these immune deficits.Domestic Animal…
| Parameter | Protocol | Outcome | Key Caveat |
|---|---|---|---|
| Starting dose | 2 μg/kg PO q24h | Licensed; effective in most horses The Veterinary…+1 | Some horses require escalation to 4 μg/kg PO q24h after 1.7–4.7 years Journal of Vete… |
| Endocrine monitoring | Basal ACTH q4–6 weeks until stable, then ongoing | 75% endocrine normalization at 5.5 years; drops to 2/6 horses at 9.5 years Journal of Vete… | <50% of monitored horses receive follow-up ACTH within 1–3 months in practice The Veterinary… |
| Onset of ACTH suppression | Within 12 hours of first dose | TRH stimulation response altered by day 8 Domestic Animal… | Steady state reached within 3 days; no drug accumulation Domestic Animal… |
| Twice-daily dosing | 2 μg/kg PO q12h (not licensed) | Pharmacokinetically supported to reduce ACTH fluctuation Domestic Animal… | Not the licensed regimen; no clinical outcome data in sources |
| Extended-release cabergoline (ERC) | 0.005 mg/kg IM q7d | Comparable endocrine and clinical response to pergolide; less inappetence than 0.01 mg/kg dose Frontiers in Ve… | Retrospective; for pergolide-refractory cases Frontiers in Ve… |
Would you like guidance on interpreting seasonal ACTH reference intervals when deciding whether to adjust the pergolide dose?