What is the first-line vasopressor in septic shock and its typical dosing consideration?

• A. Dopamine as first-line.
• B. Vasopressin as first-line.
• C. Norepinephrine; start at 0.05-0.1 mcg/kg/min to achieve MAP ≥65; monitor tachyarrhythmias; vasopressin can be added if needed.
• D. Epinephrine as first-line.

Answer: (C)

In septic shock, the goal is to restore mean arterial pressure to preserve organ perfusion after adequate fluid resuscitation. Norepinephrine is preferred as the first-line vasopressor because it provides strong alpha-adrenergic vasoconstriction to raise systemic vascular resistance and MAP, with fewer troubling heart-rate–raising side effects than dopamine. This helps improve perfusion without excessive tachycardia, which can worsen myocardial oxygen demand.

Begin norepinephrine at about 0.05–0.1 mcg/kg/min as an IV infusion and titrate up (often every few minutes) until the target MAP of 65 mmHg is reached. Monitor closely for tachyarrhythmias and signs of ischemia; adjust the dose if needed. Large or prolonged doses should prompt consideration of line placement for reliable administration and to avoid extravasation injury. If blood pressure remains borderline or the dose is high, vasopressin can be added at a fixed low dose of 0.03 units/min to help achieve the target and reduce norepinephrine requirements.