Which medications in the drug class Inotropic Agents are used in the treatment of Respiratory Failure?

Updated: Apr 07, 2020
  • Author: Ata Murat Kaynar, MD; Chief Editor: Michael R Pinsky, MD, CM, Dr(HC), FCCP, FAPS, MCCM  more...
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Answer

Inotropic Agents

The principal inotropic agents are dopamine, dobutamine, inamrinone (formerly amrinone), milrinone, dopexamine, and digoxin. In patients with hypotension who present with CHF, dopamine and dobutamine usually are employed. Inamrinone and milrinone inhibit phosphodiesterase, resulting in increased intracellular cyclic adenosine monophosphate (cAMP) and altered calcium transport. As a result, they increase cardiac contractility and reduce vascular tone by vasodilatation.

Dopamine

Dopamine is a positive inotropic agent that stimulates both adrenergic and dopaminergic receptors. Its hemodynamic effects depend on the dose. Lower doses stimulate mainly dopaminergic receptors that produce renal and mesenteric vasodilation; higher doses produce cardiac stimulation and renal vasodilation. Doses of 2-10 µg/kg/min can lead to tachycardia, ischemia, and dysrhythmias. Doses higher than 10 µg/kg/min cause vasoconstriction, which increases afterload.

Norepinephrine (Levophed)

Norepinephrine is used in protracted hypotension after adequate fluid replacement. It stimulates beta1- and alpha-adrenergic receptors, which leads to increased cardiac muscle contractility and heart rate, as well as vasoconstriction. As a result, norepinephrine increases systemic blood pressure and cardiac output. Adjust and maintain infusion to stabilize blood pressure (eg, 80-100 mm Hg systolic) sufficiently to perfuse vital organs.

Dobutamine

Dobutamine produces vasodilation and increases the inotropic state. At higher dosages, it may cause increased heart rates, thus exacerbating myocardial ischemia. It is a strong inotropic agent with minimal chronotropic effect and no vasoconstriction.


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