Which vasopressor provides both inotropic and vasopressor effects by stimulating alpha and beta-1 receptors?

Which vasopressor provides both inotropic and vasopressor effects by stimulating alpha and beta-1 receptors?

• A. Epinephrine
• B. Dopamine
• C. Norepinephrine (Levophed)
• D. Phenylephrine

Answer: (C)

Activating both alpha-1 and beta-1 receptors provides both vasoconstriction and increased cardiac contractility. Alpha-1 stimulation raises systemic vascular resistance, which boosts blood pressure, while beta-1 stimulation increases the force of heart contractions (inotropy) and can modestly raise heart rate, helping improve cardiac output. The drug that most reliably combines strong alpha-1–driven vasoconstriction with beta-1–driven inotropy is norepinephrine. Its alpha-1 effects produce the needed vasoconstriction to raise blood pressure, and its beta-1 effects enhance contractility to support forward flow, with minimal beta-2–mediated vasodilation compared with epinephrine. Other options either lack substantial inotropic effect (pure alpha-1 vasoconstrictor), have dose-dependent or broader receptor actions (dopamine), or include beta-2–mediated vasodilation (epinephrine), making norepinephrine the best match for those receptor targets.

Activating both alpha-1 and beta-1 receptors provides both vasoconstriction and increased cardiac contractility. Alpha-1 stimulation raises systemic vascular resistance, which boosts blood pressure, while beta-1 stimulation increases the force of heart contractions (inotropy) and can modestly raise heart rate, helping improve cardiac output. The drug that most reliably combines strong alpha-1–driven vasoconstriction with beta-1–driven inotropy is norepinephrine. Its alpha-1 effects produce the needed vasoconstriction to raise blood pressure, and its beta-1 effects enhance contractility to support forward flow, with minimal beta-2–mediated vasodilation compared with epinephrine. Other options either lack substantial inotropic effect (pure alpha-1 vasoconstrictor), have dose-dependent or broader receptor actions (dopamine), or include beta-2–mediated vasodilation (epinephrine), making norepinephrine the best match for those receptor targets.