What is the recommended initial dose of intravenous (IV) epinephrine in anaphylactic shock?

IV Epinephrine Dosing in Anaphylactic Shock

The recommended initial dose of intravenous (IV) epinephrine in anaphylactic shock is 0.05 to 0.1 mg (0.1 mg/mL or 1:10,000 concentration). 1

Initial Management and Route Selection

• Intramuscular (IM) epinephrine (0.3-0.5 mg of 1:1000 concentration) is the preferred first-line treatment for anaphylaxis due to ease of administration, effectiveness, and safety profile 1
• IV epinephrine should only be considered when an IV line is already in place and in specific circumstances: 2
  • Cardiac arrest from anaphylaxis
  • Profound hypotension unresponsive to IV fluids and IM epinephrine
  • Failure to respond to several injected doses of epinephrine

IV Epinephrine Administration

Bolus Dosing

• When using IV bolus, administer 0.05 to 0.1 mg (5-10% of the cardiac arrest dose) 1
• This dose has been successfully used for anaphylactic shock according to the American Heart Association (AHA) guidelines 1
• The medication should be given slowly over several minutes to minimize adverse effects 1

Continuous Infusion

• IV infusion is a reasonable alternative to repeated IV boluses 1
• Continuous infusion allows for careful titration and avoidance of epinephrine overdose 1
• Two recommended preparation methods: 1, 2
  1. Add 1 mg (1 mL) of 1:1000 epinephrine to 250 mL of D5W (concentration: 4 μg/mL)
     • Initial infusion rate: 1-4 μg/min (15-60 drops/min with microdrop apparatus)
     • Maximum rate: 10 μg/min
  2. Add 1 mg (1 mL) of 1:1000 epinephrine to 100 mL of saline (concentration: 10 μg/mL)
     • Initial infusion rate: 30-100 mL/hr (5-15 μg/min)
     • Titrate based on clinical response and side effects

Safety Considerations and Monitoring

• Continuous hemodynamic monitoring is essential when administering IV epinephrine 1, 2
• In settings without advanced monitoring, use: 2
  • Every-minute blood pressure measurements
  • Continuous pulse monitoring
  • ECG monitoring if available
• Potential adverse effects include: 2
  • Tachyarrhythmias/ectopic beats
  • Hypertension
  • Risk of potentially lethal arrhythmias
  • Extravasation causing severe skin injury

Special Considerations

• For patients with concomitant β-blocker therapy, consider glucagon (1-5 mg IV over 5 minutes followed by infusion) 1
• For refractory hypotension despite epinephrine, consider alternative vasopressors such as dopamine (2-20 μg/kg/min) 1
• In experimental models, epinephrine has shown superior outcomes compared to other vasopressors in anaphylactic shock 3
• Multiple doses may be required; studies show 8-28% of anaphylaxis patients need a second dose of epinephrine 4

Common Pitfalls to Avoid

• Using IV epinephrine as first-line treatment when IM is safer and equally effective for most patients 5
• Administering IV epinephrine too rapidly, which increases risk of adverse cardiovascular effects 1
• Delaying epinephrine administration while focusing on second-line treatments (antihistamines, steroids) 1
• Using incorrect concentration (1:1000 vs. 1:10,000) for IV administration 1
• Failing to provide continuous hemodynamic monitoring during IV epinephrine administration 2

Remember that while IV epinephrine is appropriate in severe anaphylactic shock with an established IV line, it carries greater risks than IM administration and requires careful monitoring and dosing.