Dopamine
Intropin
vasopressorIV (central line preferred)Onset: 2–5 minutesDuration: Minutes; continuous infusion
Mechanism of Action
Endogenous catecholamine precursor. Dose-dependent receptor activation: low doses (1–5 mcg/kg/min): dopaminergic D1 receptors → renal/mesenteric vasodilation. Moderate doses (5–10 mcg/kg/min): beta-1 → increased contractility and HR. High doses (>10 mcg/kg/min): alpha-1 → vasoconstriction.
Dosing
Adult
Start: 2–5 mcg/kg/min; titrate to effect. Range: 1–50 mcg/kg/min
Pediatric
Same mcg/kg/min dosing
Indications
- Cardiogenic shock (inotropic support)
- Septic shock (if norepinephrine unavailable — not first-line)
- Symptomatic bradycardia (refractory to atropine)
Contraindications
- Pheochromocytoma (catecholamine release)
- Uncorrected tachyarrhythmias (ventricular fibrillation)
- Hypovolemia (correct before use)
Side Effects
- Tachycardia / tachyarrhythmias (most common at moderate doses)
- Hypertension
- Nausea/vomiting
- Tissue necrosis with extravasation
- Increased myocardial O2 demand
Monitoring Parameters
- Heart rate and ECG (arrhythmia risk)
- Blood pressure
- Urine output
- Peripheral perfusion
Drug Interactions
- MAOIs (severe hypertension — reduce dose by 90%)
- Phenytoin (hypotension and bradycardia)
- Beta-blockers (block cardiac effects)
Clinical Pearls
- Dose-dependent effects are a classic exam topic
- Low-dose 'renal-protective' dopamine has been disproven — do not use for renal protection
- More arrhythmogenic than norepinephrine — less preferred for septic shock
- Preferred in cardiogenic shock with bradycardia (raises HR and contractility)
- Extravasation: phentolamine antidote (same as norepinephrine)
Mnemonic
💡 Dopamine Doses: 1-5 (kidneys), 5-10 (heart beta), 10+ (alpha vasoconstriction) — 'Dirty Drug'
NBRC High-Yield
- Dose-dependent effects: low = renal D1; moderate = beta-1; high = alpha-1
- More tachyarrhythmias than norepinephrine — NOT first-line for septic shock
- Low-dose renal protection is a MYTH
- Preferred for cardiogenic shock with bradycardia
- Central line required (extravasation risk)