Which adrenergic agent is used to raise blood pressure?

Which adrenergic agent is used to raise blood pressure?

• A. Isoproterenol
• B. Phenylephrine
• C. Dobutamine
• D. Norepinephrine

Answer: (D)

Raising blood pressure with an adrenergic drug relies on increasing vascular tone. Norepinephrine acts mainly on alpha-1 receptors on vascular smooth muscle, causing vasoconstriction. This increases systemic vascular resistance and raises mean arterial pressure. It also has beta-1 effects that can boost cardiac contractility and, to some extent, heart rate, helping maintain cardiac output in hypotensive states. The net result is a reliable rise in blood pressure, which is why it’s a primary vasopressor used in acute hypotension and shock. Other agents don’t fit as well for this goal. An agent that mainly stimulates beta receptors tends to raise heart rate and cause vasodilation, which can lower or destabilize blood pressure. An inotrope that increases contractility without vasoconstriction can still lower BP if afterload is reduced. An alpha-1 agonist without beta activity can raise blood pressure but may not support cardiac output effectively, whereas norepinephrine provides both vasoconstriction and some cardiac support, making it the best choice here.

Raising blood pressure with an adrenergic drug relies on increasing vascular tone. Norepinephrine acts mainly on alpha-1 receptors on vascular smooth muscle, causing vasoconstriction. This increases systemic vascular resistance and raises mean arterial pressure. It also has beta-1 effects that can boost cardiac contractility and, to some extent, heart rate, helping maintain cardiac output in hypotensive states. The net result is a reliable rise in blood pressure, which is why it’s a primary vasopressor used in acute hypotension and shock.

Other agents don’t fit as well for this goal. An agent that mainly stimulates beta receptors tends to raise heart rate and cause vasodilation, which can lower or destabilize blood pressure. An inotrope that increases contractility without vasoconstriction can still lower BP if afterload is reduced. An alpha-1 agonist without beta activity can raise blood pressure but may not support cardiac output effectively, whereas norepinephrine provides both vasoconstriction and some cardiac support, making it the best choice here.