Dobutamine is a pure β1 adrenergic agonist, and thus, acts more selectively upon the heart. It is used for heart failure and cardiogenic shock, to increase cardiac inotropy and chronotropy. Dobutamine can't be used for ischemic heart disease because it increases myocardial oxygen demand.
Dobutamine is a β1 agonist used to treat acute and reversible heart failure, such as cardiogenic shock, due to its positive inotropic action. It can also be used in CHF to increase contractility.
Dobutamine is often used in hospital settings as a pharmacological stress testing agent, to help identify coronary artery disease.
Isoproterenol is a β1 agonist which also has action on β2 receptors. This medication increases cardiac inotropy and chronotropy, as well as dromotropy. For this reason, isoproterenol is used in cases of bradycardia and torsades de pointes (only when it is from an acquired long QT syndrome).
Rarely, isoproterenol is used for asthma, as its β2 activity dilates bronchial airways.
This drug's β1 effects allow it to be helpful in treating bradycardia. However, this drug can worsen ischemia because it increases myocardial oxygen demand.
This medication is usually combined with overdrive pacing and magnesium when treating torsades de pointes. Keep in mind that isoproterenol is only used in acquired cases long of QT syndrome, which leads to torsades de pointes.
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