Epinephrine
Epinephrine — Potent Alpha-1, Beta-1, and Beta-2 Adrenergic Agonist
🧬 Mechanism of Action & Target Pathway
Pan-Adrenergic Receptor Agonism
- Low dose (0.01–0.05 mcg/kg/min): Predominant Beta-1 and Beta-2 agonism → Increased CO, HR, and bronchodilation.
- High dose (>0.1 mcg/kg/min): Alpha-1 agonism predominates → Potent systemic vasoconstriction and MAP rise.
- Beta-2 hepatic stimulation accelerates glycolysis, causing transient type B hyperlactatemia.
Pharmacokinetics & Pharmacodynamics (PK/PD) — Epinephrine
receptor occupancy⚖️ ICU Clinical Reasoning
Why I Choose It (Indications & Strengths)
- ✓First-line treatment for anaphylaxis; give IM epinephrine promptly in the anterolateral thigh unless IV epinephrine is specifically required in a monitored refractory setting.
- ✓First-line vasopressor/inotrope in Cardiac Arrest (ACLS 1 mg IV q3–5 min).
- ✓An additional vasoactive option in septic shock when norepinephrine-based therapy is insufficient; current sepsis guidance also allows epinephrine in selected patients with persistent hypoperfusion or escalating vasopressor needs.
Why I Don't (Limitations & Gaps)
- ✕Profound tachyarrhythmias and myocardial ischemia.
- ✕Causes non-hypoxic Type B hyperlactatemia (can obscure sepsis clearance).
- ✕Splanchnic vasoconstriction.
💉 Dosing & Administration Protocols
Septic-shock hypotension (current U.S. label): 0.05–2 mcg/kg/min IV infusion, titrated to the desired MAP and weaned gradually. Adult anaphylaxis: 0.3–0.5 mg IM in the anterolateral thigh; may repeat every 5–10 minutes as needed. Adult cardiac arrest: epinephrine 1 mg IV/IO every 3–5 minutes per AHA ALS guidance.
Renal Function Dosing
| CrCl Range | Dose Adjustment |
|---|---|
| Renal impairment | Current U.S. labeling does not provide a renal dose-adjustment table; titrate the infusion to hemodynamic response and monitor renal perfusion. |
Dialytic Clearance (HD / CRRT)
🩺 Organ Failure Considerations
Current labeling does not provide a renal dose-adjustment algorithm for shock infusion; titrate to effect and monitor perfusion, arrhythmia and ischemic complications.
Rapidly metabolized; no universal hepatic dose-adjustment algorithm is provided in current labeling, so titrate to effect.
⚠️ Toxicity & Safety Warnings
Major Warnings
- 🚨Tachyarrhythmias, myocardial ischemia, extravasation necrosis, severe hypertension.
🔄 Bedside Drug Interactions
| Interacting Drug | Mechanism | Clinical Consequence | Mandatory ICU Action |
|---|---|---|---|
| Non-selective Beta-Blockers | Unopposed alpha-1 stimulation | Severe hypertension and bradycardia | Use alternative inotrope. |
📊 Monitoring & TDM Protocols
Required Monitoring Parameters
- ▪ Continuous arterial blood pressure
- ▪ Heart rate and ECG rhythm
- ▪ Serum lactate and blood glucose
Evidence Status
CurrentLast Medically Reviewed
2026-08-28
Evidence Checked Through
2026-08-28
📚 Evidence Traceability & Guideline Citations
"Current labeling supports epinephrine infusion for septic-shock hypotension at 0.05–2 mcg/kg/min, titrated to MAP; AHA adult ALS recommends 1 mg every 3–5 minutes during cardiac arrest."
🩺 Bedside Patient Scenarios
Anaphylactic Shock with Airway Edema
Scenario: Severe bronchospasm and hypotension after penicillin administration.
Rationale: Reverses bronchospasm via beta-2 and corrects vasodilation via alpha-1.
🎯 Exam Traps & Board Misconceptions
Interpret lactate in the full clinical context; epinephrine can increase lactate through beta-adrenergic metabolic effects, so a rise is not by itself proof of worsening tissue hypoperfusion.
🫀 Physiology & Hemodynamics
Epinephrine
drugMechanism
Potent β1 + β2 + α1 agonism. Dose-dependent: lower doses β-dominant (inotropy/chronotropy), higher doses α-dominant (vasoconstriction).
Continue Learning
Shock: Foundational Critical Care Framework
Cellular dysoxia, DO2/VO2 physiology, the 4 shock phenotypes, dynamic fluid responsiveness (PLR/PPV) vs fluid tolerance (VExUS), and vasoactive pharmacology.
Septic Shock
The subset of sepsis with profound circulatory and cellular/metabolic abnormality — clinically identified by a vasopressor requirement to maintain MAP ≥ 65 mmHg plus lactate > 2 mmol/L despite adequate fluid resuscitation.
Septic Shock Resuscitation
2026 SSC-aligned fluids, early norepinephrine, dynamic reassessment, and perfusion endpoints
Status Asthmaticus in the ICU
Refractory bronchospasm, impending ventilatory failure, and prevention of dynamic hyperinflation
Acute Hypotension & Undifferentiated Shock
Rapid bedside hemodynamic categorization: confirming MAP < 65 mmHg, assessing peripheral perfusion, POCUS cardiac/IVC profiling, and differentiating hypovolemic, distributive, cardiogenic, and obstructive etiologies.
Refractory Shock Despite High-Dose Vasopressors
Advanced multimodal hemodynamic rescue: second-line vasopressors (vasopressin, angiotensin II), inotropic augmentation, stress-dose steroids, metabolic correction, and mechanical circulatory support evaluation.