What is the initial dosage of epinephrine (adrenaline) for refractory shock?

Initial Epinephrine Dosage for Refractory Shock

For refractory shock, the initial epinephrine dosage should be 0.1 mcg/kg/min intravenously, titrated to desired clinical effect with a range of 0.1-1.0 mcg/kg/min. 1

Pharmacological Considerations

Epinephrine is a potent vasopressor with both alpha and beta adrenergic effects that can be life-saving in refractory shock when first-line agents have failed. When administering epinephrine:

• Start at the lowest effective dose (0.1 mcg/kg/min) to minimize adverse effects 1
• Titrate carefully in increments of 0.05-0.2 mcg/kg/min every 10-15 minutes 2
• Maximum doses as high as 5 mcg/kg/min may occasionally be necessary in severe cases 1
• FDA-approved dosing range for septic shock is 0.05-2 mcg/kg/min 3

Administration Guidelines

Preparation and Delivery

• Dilute 1 mg (1 mL) of epinephrine in 100 mL of normal saline to create a 10 mcg/mL solution 2
• Administer through a central venous line whenever possible to reduce risk of extravasation 1
• If central access is unavailable, peripheral administration can be used temporarily while obtaining central access 2
• Avoid using veins of the leg in elderly patients or those with occlusive vascular diseases 3

Monitoring Requirements

• Continuous cardiac monitoring is essential
• Frequent blood pressure measurements (every minute if continuous monitoring unavailable)
• Regular assessment of tissue perfusion (capillary refill, urine output, mental status)
• Monitor for signs of digital ischemia due to peripheral vasoconstriction 2

Clinical Considerations

When to Use Epinephrine for Refractory Shock

• After failure of initial fluid resuscitation
• When first-line vasopressors (typically norepinephrine) have failed to restore adequate perfusion
• As a second-line agent in septic shock 1
• As a first-line agent in cardiogenic shock with low cardiac output 1

Potential Adverse Effects

• Tachyarrhythmias and ectopic beats
• Increased myocardial oxygen consumption
• Lactic acidosis (independent of tissue perfusion due to metabolic effects) 1
• Hyperglycemia due to inhibition of insulin and stimulation of gluconeogenesis 1
• Tissue necrosis if extravasation occurs 1

Special Situations

Extravasation Management

• If extravasation occurs, immediately infiltrate the area with phentolamine (0.1-0.2 mg/kg up to 10 mg diluted in 10 mL of 0.9% sodium chloride) 1
• This counteracts dermal vasoconstriction and may prevent tissue necrosis

Beta-Blocker Overdose

• Higher doses of epinephrine may be considered in beta-blocker overdose (Class IIb, LOE C) 1
• IV glucagon (1-2 mg) may also be required in these cases 2

Weaning Considerations

• After hemodynamic stabilization, wean incrementally over time
• Consider decreasing doses every 30 minutes over a 12-24 hour period 3
• Monitor closely for recurrence of hypotension during weaning

Cautions and Contraindications

• Use with caution in patients with coronary artery disease due to increased myocardial oxygen demand 2
• Avoid in uncorrected hypovolemia - ensure adequate fluid resuscitation first 2
• Epinephrine may be less preferable than norepinephrine in cardiogenic shock after myocardial infarction due to higher incidence of refractory shock 4
• High-dose epinephrine may be harmful in asphyxia-related shock (Class III, LOE B) 1

Epinephrine remains a critical agent in the management of refractory shock, but careful dosing, monitoring, and awareness of its metabolic effects are essential for safe and effective use.