Phenylephrine
A pure alpha-1 agonist causing veno-arterial constriction. First-line for neuraxial-induced hypotension (especially obstetrics). Rapid onset (30–60 sec), short duration. Key risk: reflex bradycardia and reduced cardiac output, particularly if hypovolemic. Use boluses (40–100 mcg) or infusion (0.5–1 mcg/kg/min). Avoid as monotherapy in cardiogenic shock.
