Drug Groups

approved

Description

A positive inotropic cardiotonic agent with vasodilator properties. It inhibits cAMP phosphodiesterase activity in myocardium and vascular smooth muscle. Milrinone is a derivative of amrinone and has 20-30 times the ionotropic potency of amrinone. [PubChem]

Indication

Indicated for the treatment of congestive heart failure.

Pharmacology

Milrinone, a synthetic dimethylxanthine derivative structurally related to theophylline and caffeine, is used in the treatment of peripheral vascular diseases and in the management of cerebrovascular insufficiency, sickle cell disease, and diabetic neuropathy.

Toxicity

LD₅₀ = 0.3 mg/L in rats

Affected Organisms

Biotransformation

There are five metabolites but the O-glucuronide represents the major pathway of biotransformation.

Absorption

Milrinone is rapidly and almost completely absorbed after oral administration. Bioavailability is 92% (in healthy volunteers).

Half Life

2.3 hours

Protein Binding

70 to 80%

Elimination

The primary route of excretion of milrinone in man is via the urine.

Distribution

* 0.38 liters/kg [intravenous injections of 12.5 mcg/kg to 125 mcg/kg to congestive heart failure patients]
* 0.45 liters/kg [intravenous infusions of 0.20 mcg/kg/min to 0.70 mcg/kg/min to congestive heart failure patients]

Clearance

* 0.13 L/kg/hr [congestive heart failure patients, following IV injections of 12.5 mcg/kg to 125 mcg/kg]
* 0.14 L/kg/hr [congestive heart failure patients, following infusions of 0.2 mcg/kg/min to 0.7 mcg/kg/min]

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