Safety of Lidocaine with Epinephrine in Toe Injections
Yes, you can safely inject lidocaine with epinephrine into toes for local anesthesia. The historical concern about using epinephrine in digits has been refuted by extensive research and clinical evidence 1.
Evidence Supporting Safety in Digits
- Multiple systematic reviews and randomized controlled trials have conclusively demonstrated that adding epinephrine to local infiltrative anesthesia is safe for use in digits, including toes 1.
- No cases of necrosis were reported in these studies, and the use of epinephrine resulted in less need for tourniquet plus faster onset and longer duration of anesthesia 1.
- The American Academy of Dermatology guidelines give a strong recommendation (Level A) for the addition of epinephrine to local anesthesia on digits 1.
Benefits of Using Epinephrine with Lidocaine
- Prolongs the duration of anesthesia by approximately 200% when used in concentrations of 1:50,000,1:100,000, or 1:200,000 1.
- Provides hemostasis, creating a relatively bloodless operating field 2.
- Reduces the need for tourniquet use during procedures 1.
- Slows mobilization of the anesthetic, reducing peak blood levels and potential systemic toxicity 1.
Recommended Technique
- Use the lowest effective concentration of epinephrine (typically 1:100,000 or 1:200,000) to provide adequate pain control and vasoconstriction 1.
- Direct infiltration into the surgical site is preferred over digital blocks when using epinephrine 3.
- Buffering the lidocaine with sodium bicarbonate can decrease the pain of injection 1.
Special Considerations and Precautions
While generally safe, be cautious in patients with:
The FDA warns against injecting epinephrine into digits when used in high concentrations as found in emergency epinephrine auto-injectors, but this does not apply to the dilute concentrations used in local anesthetics 5.
Management of Rare Complications
- In the extremely rare event of epinephrine-induced vasospasm, phentolamine can be used as a rescue medication 6.
- Have phentolamine available when performing procedures with epinephrine in digits, especially in patients with multiple risk factors for vasospasm 6.
Conclusion
The historical prohibition against using epinephrine in digits was based on outdated concerns and case reports from the early 1900s that did not involve modern anesthetic agents like lidocaine 4. Current evidence strongly supports the safety of lidocaine with epinephrine for toe injections, with significant clinical benefits including prolonged anesthesia and improved surgical field visualization 1.