Milrinone Dilution for IV Perfusion
Milrinone should be diluted to a concentration of 200 mcg/mL for IV perfusion, using 0.45% Sodium Chloride, 0.9% Sodium Chloride, or 5% Dextrose as diluents. 1
Standard Dilution Protocol
- For a 200 mcg/mL concentration, dilute 10 mL of milrinone (1 mg/mL) with 40 mL of diluent to achieve a total volume of 50 mL 1
- Alternatively, dilute 20 mL of milrinone (1 mg/mL) with 80 mL of diluent to achieve a total volume of 100 mL 1
- Compatible diluents include 0.45% Sodium Chloride Injection USP, 0.9% Sodium Chloride Injection USP, or 5% Dextrose Injection USP 1
Administration Guidelines
Loading Dose
- Standard loading dose is 50 mcg/kg administered slowly over 10 minutes 1
- The loading dose may be given undiluted, but diluting to a rounded total volume of 10 or 20 mL may simplify visualization of the injection rate 1
- Consider dividing the bolus into five equal aliquots administered over 10 minutes each if blood pressure stability is a concern 2
- In patients with low filling pressures, consider starting the infusion without a bolus to avoid excessive hypotension 3, 4
Maintenance Dose
- Standard maintenance dose is 0.5 mcg/kg/min (range: 0.375-0.75 mcg/kg/min) 1
- Infusion should be administered using a calibrated electronic infusion device 1
- Titrate to desired hemodynamic effect, not exceeding 1.13 mg/kg/day 1
Special Considerations
Renal Impairment
- Dose adjustment is required in patients with renal impairment due to significantly increased terminal elimination half-life 1, 5
- For patients with creatinine clearance of 50 mL/min/1.73m², reduce infusion rate to 0.43 mcg/kg/min 1
- For patients with creatinine clearance of 30 mL/min/1.73m², reduce infusion rate to 0.33 mcg/kg/min 1
- For patients with creatinine clearance of 10 mL/min/1.73m², reduce infusion rate to 0.23 mcg/kg/min 1
Monitoring and Safety
- Monitor hemodynamic parameters closely during infusion, particularly blood pressure 2
- Hypotension is the most common side effect due to milrinone's vasodilatory properties 2, 3
- If hypotension occurs, it can typically be reversed with titrated boluses of isotonic crystalloid or colloid 2
- Discontinue milrinone at the first sign of arrhythmia or excessive hypotension 2, 3
- Hypotension-related toxicity can potentially be overcome by beginning norepinephrine or vasopressin 2
- Milrinone can increase the risk of atrial fibrillation, particularly in post-cardiac surgery patients 3
Clinical Efficacy
- Milrinone increases cardiac index and reduces pulmonary capillary wedge pressure in heart failure patients 1, 6
- At lower doses (serum concentrations of 63-156 ng/mL), milrinone causes significant increases in stroke volume without changes in systemic vascular resistance 6
- Milrinone may be preferred over dobutamine in patients on beta-blocker therapy as its mechanism of action is distal to beta-adrenergic receptors 2, 3