Amrinone is a positive inotropic agent and phosphodiesterase inhibitor used in the treatment of congestive Cardiac failure. Now a day Amrinone is not used because of toxicity effect; long term uses shown increase mortality.
Dose of Amrinone Drugs
- Milrinone : 5 μg/kg IV bolus injection followed by 2-20 μg/kg/min infusion.
- Vesnarinone : 60 mg/day orally.
Action of Amrinone
- Amrinone inhibits the enzyme phospho- diesterase which metabolises cyclic 3,5 AMP to the inactive cyclic 5 AMP. It’s causes vasodilatation with fall in systemic vascular resistance. It’s enhances influx of calcium ions through Ca-channels. It increases the force of contraction & velocity of relaxation of cardiac muscle.
- It increases the level of a chemical messenger (cAMP), which helps the smooth muscles to relax. Amrinone is a vasodilator; thus, dilates the blood vessels to a better blood flow in to the heart.
- It also promotes the heart’s contractile ability to pump more blood.
Common side effects of Amrinone
- Hypotension on IV administration
- Arrhythmia (irregular heartbeats)
- Myocardial ischemia
- Decreased blood pressure
Contra-indications of Amrinone
- Patients with aortic Stenosis,
- Hypertrophic Cardiomyopathy,
- History of hypersensitivity to the drug.