Which drug is considered an 'ino-dilator'?

Which drug is considered an 'ino-dilator'?

• A. Isoproterenol
• B. Epinephrine
• C. Dopamine
• D. Dobutamine

Answer: (D)

Inodilators combine a rise in heart muscle contraction with vasodilation, so cardiac output improves while afterload drops. Dobutamine fits this pattern best because it primarily activates beta-1 receptors in the heart, boosting contractility and stroke volume, and it also has mild beta-2–mediated vasodilation that lowers systemic vascular resistance. This combination raises perfusion without the vasoconstriction or excessive tachycardia seen with some other agents. Other choices don’t align with the inodilator profile. Isoproterenol greatly increases heart rate and contractility with marked vasodilation but is not typically used as an inodilator in practice. Epinephrine boosts both alpha and beta effects, which can raise afterload via alpha-mediated vasoconstriction at higher doses. Dopamine’s effects vary with dose and can include vasoconstriction at higher doses, lacking the consistent inodilator action.

Inodilators combine a rise in heart muscle contraction with vasodilation, so cardiac output improves while afterload drops. Dobutamine fits this pattern best because it primarily activates beta-1 receptors in the heart, boosting contractility and stroke volume, and it also has mild beta-2–mediated vasodilation that lowers systemic vascular resistance. This combination raises perfusion without the vasoconstriction or excessive tachycardia seen with some other agents.

Other choices don’t align with the inodilator profile. Isoproterenol greatly increases heart rate and contractility with marked vasodilation but is not typically used as an inodilator in practice. Epinephrine boosts both alpha and beta effects, which can raise afterload via alpha-mediated vasoconstriction at higher doses. Dopamine’s effects vary with dose and can include vasoconstriction at higher doses, lacking the consistent inodilator action.