What is the standard Neonatal Intensive Care Unit (NICU) concentration of dopamine?

Standard NICU Dopamine Concentration

The standard NICU concentration of dopamine is 60 mcg/mL, prepared using the "Rule of 6" method: 6 × body weight (kg) = mg of dopamine diluted to 100 mL of saline, which delivers 1 mcg/kg/min at 1 mL/hour infusion rate. 1, 2

Preparation Method

The "Rule of 6" standardizes dopamine preparation across NICUs:

• Multiply 6 × infant's weight in kg = mg of dopamine 1
• Add this amount to normal saline to make a total volume of 100 mL 1
• This creates a concentration where 1 mL/hour = 1 mcg/kg/min 1, 2

For example, a 1 kg infant would receive 6 mg dopamine in 100 mL saline (60 mcg/mL concentration), and an infusion rate of 20 mL/hour would deliver 20 mcg/kg/min. 1

Dosing Range in Neonates

Initial dopamine dosing in neonates typically starts at low doses (<8 mcg/kg/min) combined with dobutamine (up to 10 mcg/kg/min), with the understanding that dopamine's effect on pulmonary vascular resistance must be considered. 3

• The therapeutic range is 2-20 mcg/kg/min, titrated to clinical effect 1, 2
• At doses <8 mcg/kg/min, dopaminergic and beta-adrenergic effects predominate 3
• At doses >10-15 mcg/kg/min, alpha-adrenergic vasoconstriction becomes significant 1
• Maximum recommended dose is 20 mcg/kg/min before escalating to epinephrine 1

Critical Safety Considerations

Dopamine infusions require meticulous attention to prevent extravasation, as tissue infiltration can cause severe ischemic injury, particularly at higher concentrations. 3, 2

• Phentolamine (0.1-0.2 mg/kg up to 10 mg diluted in 10 mL saline) should be immediately available for intradermal injection if extravasation occurs 1, 2
• The infusion bottle or syringe should be covered with protective foil to prevent light-induced breakdown 2
• Continuous hemodynamic monitoring with arterial line placement is essential 2
• Extreme caution must be exercised to avoid accidental flushing or bolus injection 2

Dose-Dependent Effects and Limitations

At doses >10 mcg/kg/min, the risk of peripheral vasoconstriction, arrhythmias, and tissue ischemia increases substantially, limiting dopamine's utility at higher doses. 1

• Doses >20 mcg/kg/min may result in significant vasoconstriction and arrhythmias 3
• Tachyarrhythmias and ectopic beats become particularly concerning above 10 mcg/kg/min 1
• Peripheral, renal, and splanchnic vasoconstriction can occur at higher doses 1

Alternative Concentration Method

An alternative preparation uses 0.6 × body weight (kg) = mg of dopamine diluted to 100 mL, where 1 mL/hour delivers 0.1 mcg/kg/min. 2 This creates a more dilute solution that may be preferred in some institutions for very low-dose infusions.

Clinical Context

When neonates fail to respond adequately to dopamine and dobutamine combination therapy, epinephrine (0.05-0.3 mcg/kg/min) should be initiated to restore normal blood pressure and perfusion. 3 Central venous access is preferred for dopamine administration, though peripheral administration is acceptable with appropriate dilution and carrier solution flow rates. 3