What is the appropriate evaluation and management for a patient who unintentionally self‑administers an epinephrine auto‑injector (EpiPen)?

Evaluation and Management of Accidental EpiPen Injection

For patients with accidental epinephrine auto-injector injection, immediately assess the injection site (most commonly digits), apply topical nitroglycerin cream for digital vasoconstriction, and consider local phentolamine injection if symptoms persist beyond 1-2 hours or worsen. 1

Immediate Assessment

Determine Injection Site

• Digital injections (fingers/thumbs) occur in 58-91% of accidental EpiPen cases, making this the most critical site to evaluate 2, 3
• Leg injections are more common with newer auto-injector designs (78% with Auvi-Q) 2
• Assess for signs of vasoconstriction: pallor, coldness, pain, and decreased capillary refill in the affected digit 1

Evaluate for Systemic Effects

• Monitor vital signs including continuous blood pressure and heart rate 4
• Assess for hypertension, tachycardia, tremor, anxiety, and palpitations—these are expected pharmacologic effects but can progress to serious complications 5, 6
• Obtain ECG monitoring if systemic absorption is suspected, particularly if inadvertent intravascular injection occurred 4, 7

Treatment Algorithm by Injection Site

For Digital (Finger/Thumb) Injections

First-line treatment:

• Apply topical nitroglycerin cream to the affected digit immediately to counteract epinephrine-induced vasoconstriction 5, 1
• Warm the affected area 5, 3

Second-line treatment (if symptoms persist >1-2 hours or worsen):

• Administer phentolamine 0.15-0.5 mg diluted in normal saline via local subcutaneous injection around the injection site 5, 1
• This alpha-adrenergic blockade directly reverses epinephrine's vasoconstrictive effects 1

For Non-Digital Injections

• Most non-digital accidental injections require only observation 3, 8
• Monitor for local tissue effects and systemic symptoms 3

Management of Systemic Complications

If Severe Hypertension or Cardiovascular Effects Develop

• Phentolamine is the drug of choice: administer 0.5-1 mg/kg IV bolus or 50-300 mcg/kg/min continuous infusion 4
• Alternative: rapidly acting vasodilators such as IV nicardipine (5 mg/hr initial infusion, titrate by 2.5 mg/hr every 15 minutes to maximum 15 mg/hr) if phentolamine unavailable 4
• Target gradual 20-25% reduction in mean arterial pressure within first hour, avoiding drops exceeding 70 mmHg systolic to prevent end-organ ischemia 4

Cardiac Monitoring

• Maintain continuous ECG monitoring and measure blood pressure every minute until stabilization 4
• Have atropine 0.5-1 mg IV immediately available for symptomatic bradycardia 4
• Prepare for temporary pacing if severe conduction abnormalities develop 4
• Beta-blockers (such as propranolol) may be needed for ventricular arrhythmias, though use caution as this can unmask alpha-adrenergic effects 6

Observation Period and Disposition

Emergency Department Evaluation

• Approximately 65% of patients with accidental injections are evaluated in emergency departments 3
• 53% of managed cases require only observation without intervention 8
• Continue monitoring for at least 4-6 hours after stabilization, as delayed cardiovascular effects including myocardial ischemia, infarction, cardiomyopathy, and arrhythmias can occur 4, 6

Discharge Criteria

• Resolution of local vasoconstriction (normal color, warmth, capillary refill in affected digit) 1
• Stable vital signs without ongoing cardiovascular effects 4
• Instruct patients to return if they develop persistent redness, warmth, swelling, or tenderness at the injection site 1

Critical Pitfalls to Avoid

Do Not Use Beta-Blockers as First-Line for Hypertension

• Beta-blockade without alpha-blockade can worsen hypertension by allowing unopposed alpha-adrenergic vasoconstriction 7
• One case report documented cardiac arrest after esmolol administration for epinephrine-induced hypertension 7
• Always use alpha-blockers (phentolamine) first for epinephrine-induced hypertension 4

Recognize That Permanent Sequelae Are Rare

• No permanent sequelae were reported in systematic reviews of 69 cases over 20 years 3
• This favorable prognosis should guide conservative management in most cases 3, 8

Document and Educate

• Use this event as an opportunity to review proper auto-injector technique 1
• Proper technique: remove safety cap, place orange/black tip against outer thigh, press firmly for 10 seconds 1
• Never place thumb or fingers over either end of the autoinjector during use—this is the most common cause of digital injection 1, 2