Pergolide
Pergolide is an ergot-derivative dopamine agonist primarily used in veterinary medicine as the **gold standard** treatment for **Pituitary Pars Intermedia Dysfunction (PPID)**, commonly known as Equine Cushing's Disease. * **Clinical Importance:** It is the most effective medical therapy for managing the clinical signs of PPID in horses, such as hypertrichosis (delayed shedding/long hair coat), lethargy, muscle wasting, and laminitis. * **Availability:** Because commercial human products were withdrawn from the US market in 2007 due to valvular heart disease risks in humans, pergolide for veterinary use is exclusively obtained via veterinary compounding pharmacies. * **Tolerance:** It is generally very well tolerated in equines, though transient anorexia may occur upon initiation of therapy.
Mecanismo: Pergolide acts as a potent, long-acting agonist at **D1 and D2 dopamine receptors** (estimated to be 10-1000 times more potent than bromocriptine). * **Mechanism in PPID:** In healthy horses, the hypothalamus releases dopamine, which tonically inhibits the pituitary pars intermedia. In horses with PPID, there is a neurodegenerative loss of these dopaminergic neurons. * **Pathway:** Pergolide replaces this lost dopamine tone → binds to **D2 receptors** on melanotropes in the pars intermedia → inhibits the hypersecretion of **pro-opiomelanocortin (POMC)** peptides (including ACTH, α-MSH, and CLIP). * This reduction in POMC peptides normalizes endocrine function and alleviates the clinical signs associated with PPID.
Dosificación por especie
- Equine 'Cushing's-like' Disease [pituitary pars intermedia dysfunction (PPID)] · Initial dose of 1 mg (total dose) per day for horses and ponies with PPID. If the horse owner is willing to administer half the dose twice daily, this may be preferable on the basis of recent pharmacokinetic data. If anorexia or temporary dullness develop, treatment should be halted for 2 days or until appetite improves, and then restarted at 0.25 mg per day for 2 days, 0.5 mg per day for 2 days, and 0.75 mg per day for 2 days. · PO · q24h or divided q12h
- Equine 'Cushing's-like' Disease [pituitary pars intermedia dysfunction (PPID)] · 1.7-5.5 micrograms/kg · PO · Varies · Dose varies considerably. The higher doses are used in the more advanced cases or those refractory to treatment at a lower dose.
- Equine 'Cushing's-like' Disease [pituitary pars intermedia dysfunction (PPID)] · 0.002 mg/kg. If no improvement is noted within 8-12 weeks, the daily dose can be increased by 0.002 mg/kg monthly up to a total dose of 0.006 mg/kg (3 mg/day for a 500 kg horse). If only a limited response is observed with 0.006 mg/kg dose, addition of cyproheptadine (0.5 mg/kg PO q12h) to pergolide therapy is recommended. · PO · q24h · Usually, only transient anorexia is recognized during the initial week of treatment and can be overcome in time or by cutting the dose in half for 2-4 days.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Hypersensitivity to pergolide or other ergot derivatives
Efectos adversos
- Anorexia/decreased appetite (up to 10% of horses during the first week)
- Colic (rare)
- Diarrhea (rare)
- Lethargy (dogs)
- Vomiting (dogs)
- Hypertension (dogs)
- Ptosis (dogs)
Interacciones farmacológicas
- Dopamine antagonists (e.g., phenothiazines) · May decrease the effects of pergolide
- Metoclopramide · May decrease the effects of pergolide
Monitorización
- Dexamethasone suppression test (baseline and at 4-8 weeks post pergolide therapy initiation, repeat in 4-8 weeks if dosage is adjusted)
- Blood glucose (baseline, and if abnormal repeat as per dexamethasone suppression test)
- Clinical signs (hair coat, weight, PU/PD, etc.)
- Periodic CBC and clinical chemistry panel
Sobredosis
Limited information is available on pergolide overdoses. * **Potential effects:** GI disturbances, CNS effects, seizures, and hypotension. * **Dogs:** Accidental ingestion has resulted in vomiting, lethargy, hypertension, and ptosis. * **Treatment:** Care is primarily supportive. Phenothiazines (dopamine antagonists) may be used to decrease CNS stimulation effects.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.