MILRINONE (Primacor)


Name: MILRINONE (PrimacorR)
Classification: inotropic agent (phosphodiesterase inhibitor)
  • increases contractility and cardiac index
  • lowers capillary wedge pressure
  • lowers pulmonary artery pressures
  • increases the rate of myocardial relaxation (lusitropic effect)
  • Loading Dose:
    • 50 mcg/kg IV over 10 minutes
    • Administer loading dose from the infusion bag; programme the infusion pump to deliver the bolus dose over 10 minutes
  • Maintenance Infusion:
    • 0.375-0.75 mcg/kg/min, adjusted to cardiac index, venous oxygen saturation or other marker of cardiac output
    • dose reduction required in renal dysfunction (e.g. infusion rate starting at 0.2 mcg/kg/min)
Administration: IV Infusion:
50 mg in 250 ml dextrose 5%, normal saline 0.9% or Ringer's Lactate
  • hypovolemia, acidosis and hypoxemia should be corrected concurrently with therapy
Adverse Effects:
  • tachycardia, a rrhythmias (supraventricular and ventricular)
  • hypotension
  • headache, angina/chest pain
  • hypokalemia
  • thrombocytopenia (0.5% vs amrinone 2.4%)
  • tremor
  • use with caution in patients with uncontrolled atrial fibrillation/flutter as will enhance AV node conduction; consider digitalizing these patients first
  • Dose adjust in renal failure
  • Long half life can result in prolonged vasodilatory effect
Monitoring Therapy:
  • continuous heart rate and ECG rhythym
  • blood pressure
  • urine output
  • central or mixed venous oxygen saturation
  • lactate
  • cardiac index if monitored
  • SVRI if monitored
  • platelet count
Adult Critical Care Protocol:
  • May be administered by IV infusion by a nurse in Adult Critical Care
  • Each loading dose and infusion rate must be ordered by physician; nurses are not approved to titrate milrinone
  • Must be administered via central venous access device
  • Continuous infusions must be administered by infusion device and the pump library must be enabled.
  • Should not be infused via the proximal injectate port (blue) of a pulmonary artery catheter. If this is the only available central venous line, it may be administered through the proximal injectate port but thermodilution cardiac output measurements must not be measured during infusion).

Lynne Kelly, Pharmacist, CCTC
Brenda Morgan, Clinical Nurse Specialist, CCTC
Last Update: January 12, 2017; Revised March 27, 2017, updated September 17, 2018