Dosing and uses of Milrinone
Adult dosage forms and strengths
infusion solution, in D5W
- 20mg/100mL
- 40mg/200mL
injectable solution
- 1mg/mL
Congestive Heart Failure
50 mcg/kg loading dose by IV push over 10 minutes, then 0.375-0.75 mcg/kg/min IV
Maintenance: 1.13 mg/kg/day
Monitor electrolytes, renal function, blood pressure
Dosing Modifications
Renal impairment
- CrCl <50 mL/min: 0.43 mcg/kg/min
- CrCl <40 mL/min: 0.38 mcg/kg/min
- CrCl <30 mL/min: 0.33 mcg/kg/min
- CrCl <20 mL/min: 0.28 mcg/kg/min
- CrCl <10 mL/min: 0.23 mcg/kg/min
- CrCl <5 mL/min: 0.2 mcg/kg/min
Pediatric dosage forms and strengths
Not FDA-approved in children
Dosage forms and strengths
infusion solution, in D5W
- 20mg/100mL
- 40mg/200mL
injectable solution
- 1mg/mL
Low Cardiac Output, Septic Shock
50 mcg/kg loading dose by IV push over 10-60 minutes, then 0.25-0.75 mcg/kg/min IV
Monitor electrolytes, renal function, blood pressure
Milrinone adverse (side) effects
>10%
Ventricular arrhythmias
1-10%
Supraventricular arrhythmia (4%)
Headache (3%)
Hypotension (3%)
Angina/chest pain (1%)
<1%
Abnormal liver function test results
Anaphylaxis
Atrial fibrillation
Bronchospasm
Hypokalemia
Injection-site reaction
Rash
Thrombocytopenia
Torsades de pointes
Tremor
Ventricular premature complex
Warnings
Contraindications
Hypersensitivity to milrinone and inamrinone
Cautions
Use caution in atrial fibrillation/flutter, hypertrophic subaortic stenosis, electrolyte abnormalities, hypotension, recent MI, severe aortic or pulmonic valvular disease, renal impairment
Severe aortic or pulmonic obstruction, acute phase after myocardial infarction (MI)
May increase risk of arrhythmias
Ensure that ventricular rate is controlled in atrial fibrillation/flutter before initiating therapy; may increase ventricular response rate
Concurrent use of disopyramide
Discontinue therapy if symptoms of hepatotoxicity (eg., increased LFTs) occur; monitor liver function
Monitor blood pressure/heart rate closely
Short-term use only
Pregnancy and lactation
Pregnancy category: C
Lactation: Unknown whether drug is excreted into breast milk; use with caution; nursing is not priority in situations where milrinone is used
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Milrinone
Mechanism of action
Phosphodiesterase inhibitor; positive inotrope with little chronotropic effect; direct vasodilator (decreases both preload and afterload)
Absorption
Onset: 5-15 min (IV)
Duration: 3-5 hr
Peak plasma time: 2 min
Therapeutic range: 100-300 ng/mL (hemodynamic effect)
Distribution
Protein bound: 70%
Vd: 0.38 L/kg (Injection); 0.45 L/kg (infusion)
Metabolism
Metabolized in liver (12%), mainly via glucuronidation
Metabolites: Milrinone O-glucuronide (activity unknown)
Elimination
Half-life: 2.5 hr
Clearance: 2.3 mL/kg/min
Excretion: Urine (95%; 83% as unchanged drug)
Administration
IV Incompatibilities
Additive: Procainamide
Syringe: Furosemide
Y-site: Furosemide, procainamide
IV Compatibilities
Solution: Most common solvents
Additive: Quinidine
Syringe: Atropine, calcium chloride, digoxin, epinephrine, lidocaine, morphine sulfate, propranolol, sodium bicarbonate, verapamiL
Y-site (partial list): Acyclovir, amiodarone, calcium chloride, calcium gluconate, ciprofloxacin, digoxin, diltiazem, dobutamine, dopamine, epinephrine, fentanyl, heparin, lorazepam, magnersium sulfate, metronidazole, midazolam, morphine sulfate, nitroglycerin, norepinephrine, potassium chloride, propofol, propranolol, quinidine, sodium nitroprusside, vancomycin
IV Preparation
Injection: Dilute in NS, 1/2NS, or D5W to 10-20 mL
Infusion: Dilute in NS, 1/2NS, or D5W to 200 mcg/mL; use undiluted if giving 20 mg/100 mL in D5W
IV Administration
Injection: Administer slowly over 10 minutes; may use undiluted for initial direct IV injection
Infusion: Administer via calibrated electronic controlled-infusion device
Storage
Store intact vials at room temperature; protect from excess heat or freezing
Diluted solution may be stored for 72 hours
