Vasopressors are agents that cause constriction of blood vessels, leading to an increase in blood pressure. Some vasopressors are also positive inotropes (capable of increasing contractility of the heart) and/or positive chronotropes (capable of increasing heart rate). Vasopressors are commonly administered intravenously in the critical care setting to treat conditions such as severe hypotension and cardiac arrest.
The hemodynamic effects of most vasopressors occur secondary to their interactions with receptors in the heart and vascular system. The receptors most relevant to the pharmacology of vasopressors are adrenoceptors. Adrenoceptors, sometimes referred to as adrenergic receptors, interact with norepinephrine, epinephrine, and chemically similar drugs (called adrenomimetic, adrenergic, or sympathomimetic agents). Adrenoceptors are classified as α- or β-adrenoceptors. The α-adrenoceptors are subdivided into α1- and α2-adrenoceptors, and β-adrenoceptors are subdivided into β1- and β2-adrenoceptors.1–3
The physiological response to adrenoceptor stimulation depends on the location...