Which drug increases cardiac output and stimulates alpha and beta receptors, commonly used in shock states?

• A. Dopamine
• B. Epinephrine
• C. Norepinephrine
• D. Phenylephrine

Answer: (A)

Dopamine fits because it has dose‑dependent actions on different receptor systems that together raise both heart performance and vascular tone. At targets where the heart’s beta-1 receptors are stimulated, it increases heart rate and contractility, boosting cardiac output. At higher doses it also activates alpha-1 receptors, causing vasoconstriction and raising systemic vascular resistance and blood pressure. This combination helps perfusion in shock by improving the amount of blood the heart ejects and by maintaining arterial pressure. Dopamine’s effects progress from dopaminergic renal vasodilation at very low doses to beta-1–mediated inotropy, then alpha-1–mediated vasoconstriction at higher doses, making it a drug classically described as increasing cardiac output while stimulating both alpha and beta receptors.