MILRINONE LACTATE

MILRINONE LACTATE (mil'ri-none) Primacor Classifications: inotropic agent; vasodilator; Therapeutic: vasodilator; inotropic agent Prototype: Inamrinone Pregnancy Category: C

Availability

1 mg/mL, 200 mcg/mL injection

Action

Member of a class of inotropic/vasodilator agents. Positive inotropic action and vasodilator, with little chronotropic activity; mode of action and structure are different from digitalis and catecholamines as well as beta-adrenergic agonists. Inhibitory action against cyclic-AMP phosphodiesterase in cardiac and smooth vascular muscle. Increases cardiac contractility.

Therapeutic Effect

Increases myocardial contractility. Therefore, increases cardiac output and decreases pulmonary wedge pressure and vascular resistance, without increasing myocardial oxygen demand or significantly increasing heart rate.

Uses

Short-term management of CHF.

Unlabeled Uses

Short-term use to increase the cardiac index in patients with low cardiac output after surgery. To increase cardiac function prior to heart transplantation.

Contraindications

Hypersensitivity to milrinone; valvular heart disease; acute MI; pregnancy (category C).

Cautious Use

Older adult; atrial fibrillation, atrial flutter; renal disease; renal impairment, renal failure; lactation. Safety and efficacy in children are not established.

Route & Dosage

Heart Failure Adult: IV Loading Dose 50 mcg/kg IV over 10 min IV Maintenance Dose 0.375–0.75 mcg/kg/min

Administration

Intravenous Note: Correct preexisting hypokalemia before administering milrinone. See manufacturer's information for dosage reduction in the presence of renal impairment. PREPARE: Loading Dose: Give undiluted or dilute each 1 mg in 1 mL NS or 0.45% NaCl.  IV Infusion: Dilute 20 mg of milrinone in D5W, NS, or 0.45% NaCl to yield: 100 mcg/mL with 180 mL diluent; 150 mcg/mL with 113 mL diluent; 200 mcg/mL with 80 mL diluent.   ADMINISTER: Loading Dose: Give 50 mcg/kg over 10 min.  IV Infusion: Give at a rate based on weight. Use a microdrip set and infusion pump.   INCOMPATIBILITIES Solution/additive: Furosemide, procainamide. Y-site: Furosemide, imipenem/cilastatin, procainamide.

• Store according to manufacturer's directions.

Adverse Effects (≥1%)

CV: Increased ectopic activity, PVCs, ventricular tachycardia, ventricular fibrillation, supraventricular arrhythmias; possible increase in angina symptoms, hypotension.

Interactions

Drug: Disopyramide may cause excessive hypotension.

Pharmacokinetics

Peak: 2 min. Duration: 2 h. Distribution: 70% protein bound. Elimination: 80–85% excreted unchanged in urine within 24 h. Active renal tubular secretion is primary elimination pathway. Half-Life: 1.7–2.7 h.

Nursing Implications

Assessment & Drug Effects

• Monitor cardiac status closely during and for several hours following infusion. Supraventricular and ventricular arrhythmias have occurred.
• Monitor BP and promptly slow or stop infusion in presence of significant hypotension. Closely monitor those with recent aggressive diuretic therapy for decreasing blood pressure.
• Monitor fluid and electrolyte status. Hypokalemia should be corrected whenever it occurs during administration.

Patient & Family Education

• Report immediately angina that occurs during infusion to physician.
• Be aware that drug may cause a headache, which can be treated with analgesics.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug