Pergolide

⚠️ Key Safety Warning: Pergolide is associated with fibrotic reactions - including cardiac valvulopathy and serosal fibrosis (pleural, pericardial, retroperitoneal). 📋 Monitoring: Baseline and regular echocardiography, chest X-ray, ESR, and U&Es are essential during therapy. 🔗 Check BNF entry for up-to-date prescribing and monitoring guidance.

🧠 About

• Pergolide is a potent ergot-derived dopamine receptor agonist once widely used in Parkinson’s disease as monotherapy or adjunct to Levodopa.
• It acts on both D₁ and D₂ receptors, mimicking dopamine to improve bradykinesia and rigidity.
• Withdrawn or restricted in many countries due to its strong association with valvular heart disease from stimulation of 5-HT₂B serotonin receptors in cardiac tissue.
• Use is now generally limited to specialist settings or historical legacy cases.

⚙️ Mode of Action

• Dopamine agonist: Directly stimulates postsynaptic dopamine receptors in the striatum.
• Ergot derivative: Its ergot backbone gives it serotonergic and adrenergic activity, explaining fibrotic side effects.
• Reduces motor symptoms and Levodopa “wearing-off” by bypassing presynaptic dopamine synthesis.
• Suppresses prolactin secretion via hypothalamic D₂ receptor stimulation.

💊 Indications & Dose

• Parkinson’s disease (Monotherapy):
  • Day 1: 50 micrograms once daily, then 50 micrograms twice daily for 2 days.
  • Increase by 100–250 micrograms/day until response achieved.
  • Target: ~1.5 mg/day in 3 divided doses by Day 28 (max 3 mg/day).
• Parkinson’s disease (Adjunct to Levodopa):
  • Start 50 micrograms once daily, then 50 micrograms twice daily for 2 days.
  • Titrate slowly by 100–150 micrograms every 3 days as tolerated (max 3 mg/day in 3 doses).
  • Often requires Levodopa dose reduction to limit dyskinesia.

🧪 Pharmacology

• Class: Ergot-derived dopamine agonist.
• Receptor profile: Agonist at D₁, D₂ and 5-HT₂B receptors.
• Half-life: ~27 hours (allows once-daily dosing after titration).
• Metabolism: Hepatic; metabolites excreted mainly in urine.
• Onset: Gradual, with full effect over several weeks.

🤝 Interactions

• Antipsychotics antagonise dopaminergic action.
• Antihypertensives: additive hypotension - monitor BP carefully.
• Macrolide antibiotics (e.g. erythromycin) increase serum levels via CYP3A4 inhibition.
• See BNF for full interaction list.

⚠️ Cautions

• Abrupt cessation can precipitate neuroleptic malignant–like syndrome.
• Orthostatic hypotension - advise gradual position changes and caution when driving.
• Drowsiness or sleep attacks may occur, especially with Levodopa co-therapy.
• Acute porphyria - avoid use.
• Impulse control disorders (gambling, hypersexuality, binge eating) - warn and monitor.
• Require regular echo and CXR monitoring for fibrotic complications.

⛔ Contraindications

• Known valvular heart disease or fibrotic disorders (pleural, pericardial, retroperitoneal).
• Severe hepatic impairment.
• Uncontrolled hypertension or ischaemic heart disease.
• Hypersensitivity to ergot alkaloids.

💢 Side Effects

• Common: nausea, dizziness, headache, orthostatic hypotension, drowsiness.
• Neuropsychiatric: hallucinations, insomnia, confusion, compulsive behaviours.
• Motor: dyskinesias and dystonia (especially with Levodopa).
• Cardiovascular: valvular fibrosis, palpitations, arrhythmia.
• Fibrotic reactions: pericardial, pleural or retroperitoneal fibrosis - stop if symptoms or raised ESR.
• Others: Raynaud’s phenomenon, peripheral oedema, GI upset.

🧠 Clinical Pearls

• Pergolide demonstrates the historical evolution of dopamine agonists - potent but limited by fibrosis risk.
• Modern practice favours non-ergot agonists (e.g. pramipexole, ropinirole, rotigotine) which are safer for long-term use.
• Any patient with unexplained dyspnoea, chest pain, ankle swelling or flank pain should have immediate investigation for fibrosis.
• Echo changes or elevated ESR warrant drug discontinuation and specialist referral.
• Always warn about behavioural disinhibition and sleep attacks.

📚 References

• BNF: Pergolide
• MHRA Drug Safety Update: “Ergot-derived dopamine agonists and fibrotic reactions.”
• NICE NG71: Parkinson’s Disease in Adults (2023 update).
• UpToDate: “Dopamine agonists in Parkinson’s disease.”