CC Pharm | Dopamine

Dose-Dependent Mechanism: Dopamine is a metabolic precursor to norepinephrine. Clinical effects depend entirely on the infusion rate: Low Dose (< 5 mcg/kg/min): Stimulates dopaminergic D1 and D2 receptors in renal, mesenteric, coronary, and cerebral beds, causing vasodilation and increasing blood flow. Intermediate Dose (5 to 10 mcg/kg/min): Stimulates dopaminergic and beta-1-receptors, increasing cardiac contractility, chronotropy, and mildly raising systemic vascular resistance. High Dose (> 10 mcg/kg/min): Stimulates alpha-receptors, causing potent vasoconstriction. Rates > 20 mcg/kg/min frequently cause arrhythmias or severe vasoconstriction. Key Indications: Dopamine provides hemodynamic support in distributive shock (e.g., septic, cardiogenic, anaphylactic, neurogenic), open-heart surgery, or renal failure. It is used for symptomatic bradycardia unresponsive to atropine or pacing, and post-cardiac arrest hypotension. It can provide short-term inotropic support in acute/chronic heart failure. Black Box Warning (Extravasation): Extravasation can cause severe tissue necrosis. Dopamine must be infused into a large vein (e.g., antecubital fossa). If extravasation occurs, immediately infiltrate the area with 10 to 15 mL of 0.9% NaCl containing 5 to 10 mg of phentolamine using a fine needle. The Supporting 80% (Operational Details) Administration & Incompatibilities: Correct hypovolemia before starting. Dilute concentrate in compatible solutions (e.g., 5% Dextrose, 0.9% NaCl) to 200–1,600 mcg/mL (standard adult infusions use 1,600 or 3,200 mcg/mL). It is completely inactivated in alkaline solutions; never add to Sodium Bicarbonate. Do not run dextrose-containing dopamine through the same line as blood to prevent hemolysis. Monitor urine flow, cardiac output, and blood pressure. Dosing: Adults: Initially 2 to 5 mcg/kg/min, titrating by 5 to 10 mcg/kg/min (Max: 50 mcg/kg/min). Pediatrics (Neonates to Adolescents): Initially 1 to 5 mcg/kg/min, titrating by 2.5 to 5 mcg/kg/min (Max: 15 to 20 mcg/kg/min). Pharmacokinetics: Administered via IV or intraosseously (during CPR). Onset is within 5 minutes, persisting under 10 minutes, with a 2-minute plasma half-life. It does not cross the blood-brain barrier significantly and is metabolized in liver, kidneys, and plasma by MAO and COMT. About 25% is converted to norepinephrine. Excreted in urine.