✅ CABERGOLINE — 20% HIGH-YIELD VERSION

⭐ Class

• Dopamine D2 receptor agonist

⭐ Mechanism (PD — What the drug does)

• Stimulates D2 receptors in anterior pituitary →

↓ Prolactin secretion

↓ Lactation

Shrinks prolactinomas

👉 Cabergoline = MOST potent prolactin suppressor.

⭐ Pharmacokinetics (PK — What the body does)

• Oral
• Long half-life: ~65 hours
• High bioavailability
• Hepatic metabolism
• Excretion: feces > urine

👉 Once or twice weekly dosing because half-life is very long.

⭐ Main Uses

• Hyperprolactinemia (first-line)
• Prolactinomas
• Stopping lactation (postpartum)
• Parkinson’s disease (rarely)

⭐ Dose

• Hyperprolactinemia:

0.25–0.5 mg twice weekly

• Suppress lactation:

Single dose 1 mg OR 0.25 mg every 12 h × 2 days

⭐ Side Effects

• Nausea
• Vomiting
• Postural hypotension
• Headache
• Dizziness
• Valvular heart disease (rare, dose-dependent)

👉 Cabergoline has far fewer side effects than bromocriptine.

⭐ Contraindications

❌ Uncontrolled hypertension

❌ Severe heart-valve disease

❌ Preeclampsia/eclampsia postpartum

❌ History of psychosis

⭐ Pregnancy Notes

• Discontinue when pregnancy confirmed
• Safe data available
• Used to shrink macroprolactinomas before conception

🟦🟦🟦

✅ OTHER DRUGS IN THE SAME CLASS (DOPAMINE AGONISTS)

✔ BROMOCRIPTINE

⭐ Class

• Dopamine D2 agonist

⭐ Mechanism

• ↓ Prolactin secretion
• ↓ GH in acromegaly
• Shorter acting than cabergoline

⭐ PK

• Oral
• Half-life: 3–7 hours
• Requires daily or twice-daily dosing

⭐ Uses

• Hyperprolactinemia
• Prolactinomas
• Parkinson’s disease
• Postpartum suppression (rare now)

⭐ Dose

• Start 1.25 mg at night → increase to 2.5 mg twice daily

⭐ Side Effects (more than cabergoline)

• Nausea/vomiting
• Dizziness
• Orthostatic hypotension
• Headache
• Cold extremities
• Rare: stroke in postpartum women (why not preferred)

⭐ Contraindications

❌ Uncontrolled HTN

❌ Severe CAD

❌ Postpartum hypertension/preeclampsia

🟦🟦🟦

✅ QUINAGOLIDE (Norprolac)

(Non-ergot dopamine agonist)

⭐ Mechanism

• Selective D2 agonist → ↓ prolactin

⭐ PK

• Oral
• Half-life: ~22 hours
• Once-daily dosing
• Non-ergot → no valvular fibrosis risk

⭐ Uses

• Hyperprolactinemia when cabergoline/bromocriptine not tolerated

⭐ Side Effects

• Nausea
• Headache
• Fatigue
• Less orthostatic hypotension than bromocriptine

🟦🟦🟦

🔥 ULTRA SUPER-SUMMARY (MEMORISE THIS)

Cabergoline

→ D2 agonist (long acting)

→ Best for hyperprolactinemia

→ Weekly dosing

→ Fewer side effects

→ Rare valvular fibrosis

Bromocriptine

→ D2 agonist (short acting)

→ More nausea + hypotension

→ Not preferred postpartum

→ Twice-daily dosing

Quinagolide

→ D2 agonist (non-ergot)

→ Daily dosing

→ No valvular disease risk

→ Good alternative if intolerance

🧠 EXAM RECALL BLOCK — Dopamine Agonists (Prolactin Control)

🔑 One-line exam reflex

• Cabergoline = first-line for hyperprolactinemia because it is long-acting, most potent, and best tolerated.

🎯 Most commonly tested comparisons

• Best drug for hyperprolactinemia → Cabergoline
• Safest in terms of GI side effects → Cabergoline
• Needs daily dosing → Bromocriptine / Quinagolide
• Non-ergot dopamine agonist → Quinagolide
• Least risk of valvular fibrosis → Quinagolide
• For Postpartum suppression not preferred → Bromocriptine
• Shrinks prolactinoma best → Cabergoline
• Contraindicated in postpartum hypertension / pre-eclampsia→ is Bromocriptine

⚠️ Classic examiner traps

• Valvular heart disease
• Seen with ergot-derived dopamine agonists
• Cabergoline → rare, dose-dependent
• Quinagolide → NO valvular risk
• Postpartum stroke risk
• Linked to bromocriptine → why it fell out of favour
• Pregnancy management
• Stop cabergoline once pregnancy confirmed, start bromocriptine
• But used pre-conception to shrink macroprolactinomas

🧩 Mechanism lock (single concept)

Dopamine inhibits prolactin →

D2 agonists mimic dopamine →

↓ prolactin, ↓ lactation, ↓ prolactinoma size

🧠 High-yield MCQ stem patterns

• “Woman with galactorrhoea + amenorrhoea” → Cabergoline
• “Drug with longest half-life among dopamine agonists” → Cabergoline
• “Alternative when ergot drugs not tolerated” → Quinagolide
• “Postpartum hypertension + dopamine agonist complication” → by Bromocriptine

🏁 Final memory hook

C-B-Q ladder

• Cabergoline → Champion (weekly, best tolerated)
• Bromocriptine → Bad nausea (old, short-acting)
• Quinagolide → Quiet valves (non-ergot backup)