ADRENALINE (EPINEPHRINE) 

 1. BASIC PHARMACOLOGY

• Endogenous catecholamine
• Secreted from adrenal medulla
• Acts on:
• α1 → vasoconstriction
• β1 → ↑ HR, ↑ contractility
• β2 → bronchodilation, vasodilation

Dose-dependent receptor activity

 2. MECHANISM OF ACTION 

Cardiovascular

• ↑ cAMP → ↑ Ca²⁺ influx → ↑ contractility (positive inotropy)
• ↑ HR (chronotropy)
• Peripheral vasoconstriction (↑ SVR)

Respiratory

• β2 → bronchodilation (key in anaphylaxis)

Metabolic

• ↑ lactate ( important ICU pitfall)

3. HEMODYNAMIC EFFECTS

4. PREPARATIONS & DILUTION

5. INDICATIONS 

A. CARDIAC ARREST (ACLS – Class I)

• Dose: 1 mg IV every 3–5 min

B. ANAPHYLACTIC SHOCK (FIRST-LINE)

• IM route preferred
• Dose: 0.3–0.5 mg IM (1:1000)

Why best drug?

• α1 → vasoconstriction (reverses shock)
• β1 → improves CO
• β2 → bronchodilation + ↓ mediator release

ONLY drug that reduces mortality in anaphylaxis

 C. SEPTIC SHOCK (SSC GUIDELINES)

• First-line: Noradrenaline
• Add adrenaline if:
• Persistent hypotension OR
• Need additional inotropy

Alternative to:

• Noradrenaline + dobutamine combination

D. CARDIOGENIC SHOCK

• Used when:
• Severe LV dysfunction + hypotension
• But:
• ↑ arrhythmias + ↑ lactate → not preferred over dobutamine/noradrenaline

E. SEVERE BRONCHOSPASM

• Life-threatening asthma (rare ICU use)

6. DOSE (ICU INFUSION)

• Start: 0.01–0.05 µg/kg/min
• Titrate up to:
• 0.5 µg/kg/min

7. SIDE EFFECTS 

Cardiovascular

• Tachycardia
• Arrhythmias (AF, VT)
• Myocardial ischemia

Metabolic

• Lactic acidosis 
• Hyperglycemia
• Hypokalemia

Peripheral

• Extravasation → tissue necrosis

8. SPECIAL ICU CONCEPTS 

 1. Lactate Paradox-type B lactic acidosis

• Mechanism:
• β2 stimulation → ↑ glycolysis → ↑ pyruvate → ↑ lactate
• Interpretation:
• Not always hypoxia
• Seen in septic shock on adrenaline

 2. Splanchnic Circulation

• ↓ gut perfusion → risk of ischemia

 3. Arrhythmogenic Potential

• More arrhythmias vs noradrenaline
   Important in cardiogenic shock

9. ADRENALINE vs NORADRENALINE