Dopamine

# dopamine ## Overview - **Classification**: Sympathomimetic, vasopressor, inotropic agent. - **Mechanism**: Dose-dependent effects on dopaminergic, beta-1, and alpha-1 receptors. Low doses: renal vasodilation. Moderate doses: increased cardiac contractility/rate. High doses: peripheral vasoconstriction. ## Primary Indications 1. **Hemodynamic Support**: Correction of hypotension and low cardiac output in shock (e.g., cardiogenic, septic shock). 2. **Symptomatic Bradycardia**: Alternative to epinephrine for bradycardia unresponsive to atropine. ## Adult Dosing ### Standard Dosing **Hemodynamic Support (Shock)** - **Dose**: Start **2-5 mcg/kg/min** IV infusion. - **Frequency**: Titrate by **1-4 mcg/kg/min** increments q 10-30 min to desired effect. - **Route**: Continuous IV infusion. Central line preferred. - **Maximum Dose**: Typically up to **20 mcg/kg/min**, rarely higher. **Symptomatic Bradycardia** - **Dose**: **5-20 mcg/kg/min** IV infusion. - **Frequency**: Titrate to desired heart rate/blood pressure. - **Route**: Continuous IV infusion. ### Dose Adjustments - **Renal Impairment**: No specific dose adjustments required; monitor fluid status. - **Hepatic Impairment**: No specific dose adjustments. - **Elderly Patients**: Start at lower end of dosing range due to increased sensitivity to adverse effects. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: Start **2-5 mcg/kg/min** IV infusion. - **Frequency**: Titrate q 5-10 min to desired effect. - **Maximum**: Up to **20 mcg/kg/min**. - **Special Notes**: Use lowest effective dose. Monitor for arrhythmias. Central line preferred. ### Infants (1-12 months) - **Dose**: Start **2-5 mcg/kg/min** IV infusion. - **Frequency**: Titrate q 5-10 min to desired effect. - **Maximum**: Up to **20 mcg/kg/min**. ### Children (1-12 years) - **Dose**: Start **2-5 mcg/kg/min** IV infusion. - **Frequency**: Titrate q 5-10 min to desired effect. - **Maximum**: Up to **20 mcg/kg/min**. ### Adolescents (13-18 years) - **Dose**: Approach adult dosing; start **2-5 mcg/kg/min** IV infusion. - **Maximum**: Up to **20 mcg/kg/min**. ## Safety Information ### Contraindications - **Absolute**: Pheochromocytoma (risk of hypertensive crisis). - **Absolute**: Uncorrected tachyarrhythmias or ventricular fibrillation. - **Relative**: Hypovolemia (correct before initiation). ### Common Adverse Effects - **Very Common (>10%)**: Tachycardia, palpitations, chest pain, arrhythmias. - **Common (1-10%)**: Nausea, vomiting, headache, dyspnea, piloerection. - **Serious but Rare**: Extravasation leading to tissue necrosis, severe hypertension, gangrene. ### Key Drug Interactions - **MAO Inhibitors (MAOIs)**: Potentiates pressor effect; severe hypertension. Avoid concurrent use. - **Beta-blockers**: May antagonize cardiac effects of dopamine. - **Alpha-blockers**: May antagonize peripheral vasoconstriction. - **Diuretics**: Additive effect on urine flow; monitor for electrolyte imbalances. ## Monitoring & Follow-up - **Before Treatment**: Assess volume status, obtain baseline vital signs (HR, BP), ECG. - **During Treatment**: Continuous BP, heart rate, ECG, central venous pressure (if available). - **Clinical Signs**: Monitor urine output, peripheral perfusion, and for signs of ischemia (e.g., chest pain). Closely inspect IV site for extravasation. ## Clinical Pearls - 💡 **Tip 1**: Always correct hypovolemia *before* initiating dopamine to maximize efficacy and minimize side effects. - 💡 **Tip 2**: Administer via central venous catheter when possible due to risk of tissue necrosis with extravasation. - 💡 **Tip 3**: If extravasation occurs, infiltrate the affected area with **phentolamine 5-10 mg** diluted in **10-15 mL** normal saline. - 💡 **Tip 4**: "Renal dose" dopamine (**1-3 mcg/kg/min**) is **not** supported by evidence for renal protection and should be avoided. - 💡 **Tip 5**: Dopamine is often considered a second-line vasopressor to norepinephrine in septic shock. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.