Calculating Weight-Based Dopamine Dose and Drip Rate: Step-by-Step Guide
For a 70-kg adult requiring dopamine infusion, start with a standard concentration of 800 mcg/mL (400 mg in 500 mL D5W), begin at 5 mcg/kg/min (350 mcg/min), which equals 26 mL/h on the infusion pump. 1
Step 1: Prepare Standard Concentration
- Mix 400 mg dopamine in 500 mL D5W to create 800 mcg/mL concentration 1
- Alternative concentrations available: 1600 mcg/mL or 3200 mcg/mL for fluid-restricted patients 1
- Use only clear, slightly yellow or lighter solutions; discard if darker 1
Step 2: Calculate Desired Dose in mcg/min
Formula: Dose (mcg/kg/min) × Weight (kg) = Total mcg/min
For initial dosing in a 70-kg adult:
- Low-dose (renal/mesenteric): 2-5 mcg/kg/min = 140-350 mcg/min 1, 2
- Moderate-dose (inotropic): 5-10 mcg/kg/min = 350-700 mcg/min 1, 2
- High-dose (vasopressor): 10-20 mcg/kg/min = 700-1400 mcg/min 1, 2
Example calculation for 5 mcg/kg/min:
- 5 mcg/kg/min × 70 kg = 350 mcg/min
Step 3: Convert mcg/min to mL/h Drip Rate
Formula: (mcg/min ÷ concentration in mcg/mL) × 60 min/h = mL/h
Using 800 mcg/mL concentration:
- (350 mcg/min ÷ 800 mcg/mL) × 60 = 26.25 mL/h (round to 26 mL/h) 1
Quick Reference Table for 70-kg Adult (800 mcg/mL concentration):
| Dose (mcg/kg/min) | Total mcg/min | Drip Rate (mL/h) |
|---|---|---|
| 2 | 140 | 10.5 |
| 5 | 350 | 26 |
| 10 | 700 | 52.5 |
| 15 | 1050 | 79 |
| 20 | 1400 | 105 |
Step 4: Titration Protocol
- Start at 2-5 mcg/kg/min for patients likely to respond to modest increases 1
- Start at 5 mcg/kg/min for seriously ill patients 1
- Increase in 5-10 mcg/kg/min increments every 10-15 minutes 1
- Maximum typical dose: 20-50 mcg/kg/min (1400-3500 mcg/min = 105-262 mL/h for 70-kg adult) 1
- Doses >50 mcg/kg/min have been used safely but require frequent urine output monitoring 1
Step 5: Administration Requirements
- Use only an infusion pump, preferably volumetric 1
- Infuse into large vein (antecubital fossa preferred) to prevent extravasation necrosis 1
- Never mix with sodium bicarbonate or alkaline solutions (dopamine is inactivated) 1
- Ensure central venous pressure 10-15 cm H₂O or pulmonary wedge pressure 14-18 mmHg before starting 1
Step 6: Monitoring Parameters
- Blood pressure and heart rate continuously during titration 1
- Urine output hourly (decrease in flow despite adequate BP warrants dose reduction) 1
- Watch for disproportionate diastolic rise (marked decrease in pulse pressure indicates excessive vasoconstriction) 1
- Monitor for tachyarrhythmias (reason to decrease or suspend dosage) 1
Critical Pitfalls to Avoid
- Never administer by gravity drip alone—always use infusion pump 1
- Never give as bolus—inadvertent bolus administration can cause severe complications 1
- Do not abruptly discontinue—gradually decrease dose while expanding blood volume with IV fluids to prevent marked hypotension 1
- Avoid umbilical artery catheter administration 1
- More than 50% of patients respond adequately to <20 mcg/kg/min; escalating beyond this requires careful reassessment 1