Vasopressors
Formal Definition
Inotropic and vasopressor medications used to support blood pressure and cardiac output in shock states; act by increasing systemic vascular resistance (vasopressors: norepinephrine, phenylephrine, vasopressin), increasing cardiac contractility (inotropes: dobutamine, milrinone), or both (epinephrine, dopamine); administered via central venous access with titration to MAP goals.
How It's Used on the Ward
Vasopressors or pressors or on a drip — IV medications to raise the blood pressure; used when fluids alone are not enough to keep the patient alive.
Example
"Septic shock patient still hypotensive at 78/42 despite 4L crystalloid bolus. Norepinephrine started via central line at 0.05 mcg/kg/min, titrated up to 0.12 mcg/kg/min to achieve MAP >65. Vasopressin added at 0.03 units/min when norepinephrine >0.2. Peripheral norepinephrine acceptable as bridge while central line placed in emergency."
Clinical Context
Norepinephrine (NE): first-line vasopressor in most shock states — alpha1 (vasoconstriction) + some beta1 (inotropy). Dose range: 0.01-3 mcg/kg/min. Epinephrine: beta1 > alpha1 at lower doses; preferred in cardiac arrest and anaphylaxis. Vasopressin: non-catecholamine; used as adjunct to NE to reduce NE dose; direct V1 receptor agonist. Dopamine: dose-dependent (low = dopaminergic, medium = beta1, high = alpha1) — largely replaced by NE in evidence-based guidelines. Dobutamine: beta1 agonist, increases contractility and cardiac output; causes vasodilation → may worsen hypotension; used for cardiogenic shock with low output. Milrinone: phosphodiesterase inhibitor, increases contractility and causes vasodilation; no increased arrhythmia risk vs dobutamine.