Is it safe to use epinephrine (epi) in a digital block?

Using Epinephrine in Digital Blocks: Safety and Recommendations

Yes, it is safe to use epinephrine in digital blocks based on current evidence, which has debunked the historical prohibition against this practice. 1

Evidence Supporting Epinephrine Use in Digital Blocks

• Multiple systematic reviews and randomized controlled trials have demonstrated that adding epinephrine to local infiltrative anesthesia is safe for use in digits, hands, and feet 1
• No cases of digital necrosis have been reported in studies using commercially prepared epinephrine with local anesthetics 2, 3
• The use of epinephrine provides several benefits including less need for tourniquets, faster onset, and longer duration of anesthesia 1
• The American Academy of Dermatology guidelines give an "A" strength recommendation (highest level) for the addition of epinephrine to local anesthesia on digits 1

Physiological Effects and Safety Profile

• Doppler ultrasound studies show that while epinephrine does cause vasoconstriction in digital arteries, this effect is temporary and resolves within 60-90 minutes 4
• The vasoconstrictive effect is not persistent enough to cause tissue damage in healthy patients 4, 5
• At least 2,797 documented digital nerve blocks with epinephrine have been performed without complications according to literature reviews 5

Recommended Concentrations and Technique

• The most commonly used and safe concentrations of epinephrine in dermatologic surgery are 1:100,000 and 1:200,000 1
• Concentrations of 1:50,000,1:100,000, and 1:200,000 all show similar effects on vasoconstriction and can prolong anesthetic duration by approximately 200% 1
• Use the lowest effective concentration of epinephrine to minimize potential side effects such as palpitations and anxiety 1

Special Considerations and Precautions

• While generally safe, consider patient-specific factors before using epinephrine in digital blocks:
  • Patients with stable cardiovascular conditions can safely receive local anesthesia with epinephrine 1
  • Avoid in patients with severe peripheral vascular disease, Raynaud's phenomenon, or uncontrolled hypertension 2
  • Have phentolamine available as a rescue medication (0.1–0.2 mg/kg up to 10 mg diluted in 10 mL of 0.9% sodium chloride) to reverse potential epinephrine-induced vasoconstriction if needed 1, 6

Historical Context

• The prohibition against epinephrine use in digits was based on case reports from the early 20th century involving older anesthetic compounds (cocaine, procaine) and non-standardized mixing methods 2, 3
• Other contributing factors in historical cases of digital necrosis included inappropriate tourniquet use, postoperative hot soaks, infection, or excessive anesthetic volumes—not the epinephrine itself 2
• No cases of digital gangrene have been reported with modern commercial lidocaine-epinephrine preparations 2, 3

In conclusion, the historical prohibition against using epinephrine in digital blocks has been refuted by modern evidence. When used appropriately in standard concentrations (1:100,000-1:200,000), epinephrine provides significant benefits in digital anesthesia without causing tissue necrosis.