Anaes · Anaesthetic adjuncts

Dobutamine and dopamine

Also known as Beta-1 inotrope (dobutamine) · Dose-dependent dopamine · Synthetic and natural catecholamines · Renal-dose dopamine (disproven concept)

Dobutamine and dopamine are the two inotropic catecholamines most often paired in anaesthesia and intensive-care exams because they share a beta-1 inotropic core yet diverge sharply in their receptor breadth and their adverse-effect profile. DOBUTAMINE is a SYNTHETIC catecholamine whose dominant action is BETA-1 agonism, giving increased contractility and cardiac output while remaining VASODILATING at clinical doses (beta-2 offsets alpha-1, so systemic vascular resistance and pulmonary capillary wedge pressure fall); it causes less tachyarrhythmia than dopamine or adrenaline and is the prototypical inotrope for acute heart failure and cardiogenic shock, and the standard pharmacological stressor for dobutamine stress echocardiography (Dippenaar 2026). DOPAMINE is the natural precursor of noradrenaline and acts both directly and indirectly (the latter by releasing noradrenaline from sympathetic nerve terminals), and its exam-defining feature is DOSE-DEPENDENT receptor selectivity: LOW infusion doses (1 to 3 mcg per kg per min) recruit DOPAMINE-1 (D1) receptors causing renal and mesenteric vasodilation, MODERATE doses (3 to 10 mcg per kg per min) recruit BETA-1 giving inotropy, and HIGH doses (above 10 mcg per kg per min) recruit ALPHA-1 giving vasoconstriction (Routkevitch 2026). The historical low-dose renal-dose dopamine concept has been DISPROVEN: low-dose dopamine increases urine output through D1-mediated natriuresis but does NOT prevent acute kidney injury or improve renal outcomes, and the practice is now discouraged (Routkevitch 2026, Dong 2026). Dopamine is more arrhythmogenic than dobutamine because its indirect noradrenaline release supercharges beta-1 stimulation, and it raises pulmonary vascular resistance (caution in pulmonary hypertension); both drugs share a short half-life of about 2 minutes, metabolism by catechol-O-methyltransferase (COMT), tachyphylaxis after 48 to 72 hours from beta-receptor downregulation, and extravasation necrosis reversed by phentolamine. Dopamine remains a first-line option in neonatal fluid-refractory septic shock (Yahya 2026) and a historically entrenched agent for symptomatic bradycardia, while dobutamine is the cleaner pure inotrope and the stress-testing pharmacological agent; the choice between them is increasingly informed by vasopressor-selection and delirium considerations in older adults (Dong 2026). Built on the prognostic dobutamine stress echocardiography study (Dippenaar 2026), the spinal cord blood flow and adrenergic challenge study on dopamine (Routkevitch 2026), the vasopressor selection and postoperative delirium study (Dong 2026), the neonatal septic shock first-line vasopressor study (Yahya 2026).