Vasopressors and Inotropes: Receptor and Selection Guide

Seven agents. Each one has its own page with the full detail. Doses are IV unless stated. Weight-based doses use the stated dosing weight.

1. Classify the shock first. Check the MAP, then the perfusion picture: lactate, mental status, urine output and skin. Add cardiac output or ECG and echo findings. Fluids go in before pressors when volume is not adequate.
2. Start norepinephrine for MAP below target. Titrate to MAP 65 mmHg. Without central access yet, start it peripherally (see Field & Transport).
3. Add the second agent by the physiology. Escalating norepinephrine means adding vasopressin. Still low MAP means epinephrine. Low output with cardiac dysfunction and persistent hypoperfusion: add dobutamine to norepinephrine, or use epinephrine alone.
4. Re-check perfusion after each change. Lactate, mental status, urine output and the arterial waveform tell you whether the agent helped. Reduce or stop an agent that causes tachyarrhythmia, ischemia or falling output.
5. Monitor the pressure directly when needed. SSC 2026 suggests invasive or noninvasive monitoring (conditional). Invasive arterial monitoring is advised when the patient is on intermediate-to-high vasopressor doses, escalating or multiple vasopressors, frequent arterial sampling, or inconsistent cuff readings.
6. Consider corticosteroids in septic shock. SSC 2026 suggests IV corticosteroids. That is conditional, with low certainty. Shock reversal at 7 days is high certainty. Panel practice: hydrocortisone 200 mg per 24 hours, mostly as intermittent doses.

Check these labs with it: Lactate for perfusion. Potassium for arrhythmia risk with catecholamines and inotropes.

Shock Pattern to First Step

Receptor Activity and Main Effect

• Example: dobutamine 5 mcg/kg/min in an 80-kg adult from a 1,000 mcg/mL bag: 5 × 80 × 60 ÷ 1,000 = 24 mL/hr.
• Units check: Read the unit before you trust the number. 0.1 mcg/kg/min in an 80-kg adult is 8 mcg/min. Vasopressin runs in units/min, not units/hr: 0.03 units/min is 1.8 units/hr.
• Dosing weight: Write actual, ideal or lean weight on the order. The label formula uses the dosing weight in kg. The epinephrine premix label specifies ideal body weight for dosing. Other agents follow their label and local protocol.
• Epinephrine premix titration (label): 0.05–2 mcg/kg/min range; step 0.05–0.2 mcg/kg/min every 10–15 minutes; after stabilization, wean every 30 minutes over 12–24 hours.

The formula comes from the dobutamine in dextrose label (DailyMed). Premixed products come in fixed concentrations, so read the bag and not your memory.

• Pediatrics: SSC Pediatric 2026 suggests epinephrine or norepinephrine over dopamine in septic shock. These are weak recommendations. It does not prefer one of the two as first-line. Dopamine may stand in only if neither is readily available. Peripheral start is suggested while central access is pending. The dopamine label gives 2–5 mcg/kg/min as the starting dose in adults and pediatric patients. For high-dose catecholamine needs, SSC Pediatric 2026 suggests adding vasopressin or titrating catecholamines further (weak). Vasopressin use in children is PICU-specialist, per protocol. For peri-arrest and arrest, follow PALS 2025 (AHA Part 8). For other agents, follow the PICU protocol and see Weight-Based Dosing.
• Older adults: For adults aged 65 or older, SSC 2026 suggests an initial MAP of 60–65 mmHg. Not the 65 mmHg target. That is a conditional recommendation with low certainty.
• Renal impairment: Milrinone is renally cleared, so it builds up. Reduce the rate per the label. Watch for prolonged hypotension and arrhythmia after stopping.
• Pregnancy: Vasopressor use in pregnancy is specialist and obstetric-guided. Don't withhold or delay life-sustaining treatment over fetal concern (dopamine and epinephrine labels). Address hypovolemia first (dopamine label). Vasostrict may cause tonic uterine contractions. Vasopressin clearance rises in the second and third trimesters, so the dose may need to increase (label). In arrest, AHA 2025 Part 10 calls for left lateral uterine displacement and a resuscitation team.

• Error: Mixing up dopamine and dobutamine. Both run in mcg/kg/min. Dopamine is a pressor. Dobutamine is an inotrope. Read the drug name on the bag and on the pump.
• Error: Units. Norepinephrine labeling runs in mcg/min. Vasopressin runs in units/min. Weight-based pressors run in mcg/kg/min. Entering a mcg/kg/min order as mcg/min is a large error.
• Error: Using an inotrope alone for hypotension. SSC 2026 says inotropes go on top of vasopressors, not in place of them.
• Error: Stopping dopamine or norepinephrine abruptly. Wean gradually, with volume support. That's how you avoid rebound hypotension.
• Error: Chasing the label target. The norepinephrine label describes a usual systolic pressure of 80–100 mmHg. SSC 2026 uses MAP 65 mmHg. The protocol that governs the patient is the one you follow.
• Error: Stopping vasopressin too fast. The label says taper by 0.005 units/min per hour after 8 hours off catecholamines.
• Superseded: The 2021 Surviving Sepsis Campaign guideline is replaced by the 2026 edition. SSC 2026 does not use angiotensin II or terlipressin first-line in septic shock. Norepinephrine is suggested over angiotensin II. Terlipressin is suggested against.
• Error: Treating IV vasoactive infusions as routine. IV adrenergic agonists (for example epinephrine, norepinephrine, phenylephrine) and IV vasopressin sit on the ISMP high-alert medication list for acute care. Run an independent double-check of drug, concentration and rate at each change.

• Peripheral start: SSC 2026 suggests starting vasopressors peripherally to restore MAP, not waiting for central access. That is conditional, with very low certainty. The data are insufficient to recommend a line size, site or duration. Midline catheters were not considered. Avoid leg veins in elderly patients or in occlusive vascular disease (epinephrine label).
• Extravasation: Stop the infusion. Aspirate what remains in the catheter if feasible. Elevate the limb and treat per protocol. Phentolamine infiltration within 12 hours is the usual antidote. Dose varies by protocol. The labels give 5–10 mg phentolamine in 10–15 mL saline for adults. The dopamine label gives 0.1–0.2 mg/kg, max 10 mg, for pediatric patients. Follow local protocol and medical direction.
• Transport: Hand off the agent, the concentration, the current rate in mcg/kg/min and mL/hr, the MAP goal, the last dose change and the access site. Carry the pump settings and the concentration sheet.
• Scope: Which agents and infusions EMS or transport teams may start, titrate or continue varies by state and agency protocol. Check yours. Push-dose pressors are not covered here. AHA 2025 Part 9 says push-dose vasopressors need careful dosing. It also notes that medication errors and adverse hemodynamic effects have been reported.