vasoaktiven

Vasoactive, or vasoaktiven in Swedish, describes substances that influence vascular tone by acting on the smooth muscle of blood vessels. Vasoactive agents can constrict or dilate vessels, thereby changing systemic and regional blood flow and blood pressure. They are used in medicine to manage conditions such as shock, hypertension, and perioperative hemodynamics.

Mechanisms vary by substance. Many vasoactive drugs act on receptors in vascular smooth muscle or the endothelium, altering calcium signaling, nitric oxide, and other mediators of contraction and relaxation. Adrenergic agonists may induce vasoconstriction through alpha receptors or vasodilation through beta receptors in specific beds, while other agents modify cGMP or potassium channels.

Endogenous vasoactive mediators include norepinephrine, epinephrine, angiotensin II, vasopressin, and endothelin-1. These substances regulate baseline vascular tone and respond to physiologic stress by altering vessel diameter and resistance.

Pharmacologic agents are grouped into vasopressors, which raise blood pressure by increasing vascular tone, and vasodilators, which lower vascular resistance. Examples of vasopressors include norepinephrine, epinephrine, phenylephrine, and vasopressin. Vasodilators include nitroprusside, nitroglycerin, hydralazine, calcium-channel blockers, and phosphodiesterase inhibitors such as milrinone in certain contexts.

Clinical use requires careful monitoring of blood pressure, heart rate, and organ perfusion, with attention to adverse effects such as tissue ischemia from excessive vasoconstriction, reflex tachycardia, arrhythmias, and hypotension when vasodilators are used. Dosing is tailored to patient condition, and therapy aims to balance perfusion with vascular resistance.