Inotropes and vasopressors

Abstract

Inotropic agents are used to increase myo-cardial contraction while vasopressors are used to increase vascular tone. They are often used for treatment of patients whose tissue perfusion is insufficient to meet metabolic requirements. Therefore, these agents are usually administered in inten-sive care units where continuous and inva-sive monitoring of cardiac function can be applied.Inotropic agents can be divided into those that increase cAMP levels and those that do not. Adrenergic receptor agonists and phosphodiesterase inhibitors (PDEi) in-crease cAMP levels and are currently the mainstay of positive inotropic therapy. Le-vosimendan acts as calcium sensitizer and increases myocardial contraction force without increasing intracellular calcium levels. In addition to existing inotropic agents, new promising inotropes are be-ing developed. These include sarcoplasmic reticulum calcium pump (istaroxime), cardiac myosin activators (omecamtivme-carbil), gene therapy, nitroxyl donors and ryanodine receptor stabilizers.Current treatments of heart failure are aimed at prolonging survival and not just alleviating symptoms. This review pro-vides a short description of the physiology of myocardial contraction and adrenergic receptors. We also provide a short descrip-tion of commonly used inotropic agents and vasopressor drugs as well as a short re-view of agents that are expected are in use in the future.Inotropes are agents used to increase myo-cardial contractility, while vasopressors are administered to increase vascular tone (1). Their use ismostly confined to critically ill patients whose hemodynamic impairment is such that tissue perfusion is insufficient to meet metabolic requirements (2). Pa-tients in need of inotropic or vasopressor support are often presented with septic or cardiogenic shock and severe heart failure, and are victims of major trauma or un-dergoing major surgery.These drugs are therefore administered usually to patients treated in intensive care settings where continuous monitoring of cardiac rhythm, arterial oxygenation, urine output and other invasive hemodynamic monitoring can be applied.Inotropic and vasopressor drugs should be administered through a central venous catheter via infusion pumps that can deliver precise flow rates. These agents are mostly short acting with rapid onset and offset of action. Therefore, they can be used without an initial bolus and can be titrated frequently. Abrupt dis-continuation should be avoided because of possible hypotension.