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 * **Availability:** Because commercial human products were withdrawn from the US market in 2007 due to valvular heart disease risks in humans, pergolide for veterinary use is exclusively obtained via veterinary compounding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.
กลไกการออกฤทธิ์: 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.
ขนาดยาตามชนิดสัตว์
- 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.
ขนาดยาเป็นข้อมูลอ้างอิงทางคลินิกสำหรับสัตวแพทย์ผู้มีใบอนุญาต โปรดตรวจสอบกับฉลากล่าสุดและผู้ป่วยแต่ละรายเสมอ
วิธีการให้ยา
ข้อห้ามใช้
- Hypersensitivity to pergolide or other ergot derivatives
อาการไม่พึงประสงค์
- Anorexia/decreased appetite (up to 10% of horses during the first week)
- Colic (rare)
- Diarrhea (rare)
- Lethargy (dogs)
- Vomiting (dogs)
- Hypertension (dogs)
- Ptosis (dogs)
อันตรกิริยาระหว่างยา
- Dopamine antagonists (e.g., phenothiazines) · May decrease the effects of pergolide
- Metoclopramide · May decrease the effects of pergolide
การติดตาม
- 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
การได้รับยาเกินขนาด
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.
ข้อมูลอ้างอิงยาของ VetSheet มีไว้สำหรับสัตวแพทย์ผู้มีใบอนุญาตเพื่อช่วยในการตัดสินใจทางคลินิก ไม่ใช่สิ่งทดแทนการวินิจฉัยของผู้เชี่ยวชาญหรือฉลากล่าสุดของผู้ผลิต