A catecholamine neurotransmitter and hormone (153 D), formed by decarboxylation of dehydroxyphenylalanine (dopa). A precursor of adrenaline and noradrenaline.

Pharmacologic action: 1. Precursor of norepinephrine 2. Stimulates dopaminergic, alpha and beta-1 adrenergic receptors: 3. Dopaminergic (1-2 mcg/kg per min): cerebral, renal, and mesenteric vasodilation increase urine output 4. Mixed alpha and beta-1 (2-10 mcg/kg per min): increases cardiac ouput with moderate increase systemic vascular resistance 5. Predominantly alpha (>20 mcg/kg per min): increases systemic vascular resistance

Uses: 1. Treat hypotension associated with bradycardia 2. Stimulate cardiac output and urine output

Dose: 1. Start infusion at 1-5 mcg/kg per min and titrate to effect. 2. Use the lowest dose that provides the desired hemodynamic improvement. 3. Do not exceed 20 mcg/kg per min.

Potential complications: 1. May increase pulmonary pressure and worsen pulmonary congestion. 2. May increase myocardial work without improving coronary blood flow, exacerbating myocardial ischaemia 3. Stimulates heart rate and may cause supraventricular or ventricular arrhythmias

(15 Mar 2000)