Yes, Lidocaine with Epinephrine is Safe for Great Toe Ring Blocks
You can and should use lidocaine with epinephrine for ring blocks of the great toe—the historical prohibition against epinephrine in digits has been thoroughly refuted by extensive research and current guidelines explicitly recommend this practice. 1, 2
Guideline-Based Recommendations
The American Academy of Dermatology provides an "A" strength recommendation supporting the addition of epinephrine to local anesthesia for digits, hands, and feet, based on multiple systematic reviews and randomized controlled trials demonstrating safety with no cases of necrosis reported. 1, 2
Key benefits of using epinephrine in digital blocks include: 1, 2
- Faster onset of anesthesia (2-5 minutes)
- Prolonged duration of action (90-200 minutes, approximately 200% longer than plain lidocaine)
- Superior hemostasis during the procedure
- Reduced need for tourniquets
- Lower systemic absorption and reduced toxicity risk
Recommended Technique and Dosing
Use commercially prepared lidocaine with epinephrine at concentrations of 1:100,000 or 1:200,000—these are the safest and most commonly used concentrations. 1, 2
For a great toe ring block, the maximum safe dose is 7.0 mg/kg of lidocaine with epinephrine in adults (up to 490 mg or 49 mL of 1% solution for a 70 kg adult). 2 A typical ring block requires only 3-5 mL, well below toxic thresholds. 2
To minimize injection pain, buffer the lidocaine with sodium bicarbonate in a 1:9 or 1:10 ratio (bicarbonate to lidocaine). 3
The Evidence Debunking the Historical Myth
The prohibition against epinephrine in digits stems from outdated case reports, but careful analysis reveals critical flaws: 4, 5
- Of 48 reported cases of digital gangrene after anesthetic blocks (1880-2000), only 21 involved epinephrine, and 17 of these used unknown concentrations based on manual dilution 5
- Zero cases of digital necrosis have been reported with commercial lidocaine-epinephrine preparations 4, 5
- Historical cases involved older compounds (cocaine, procaine, eukaine), non-standardized mixing methods, concurrent use of tourniquets, hot soaks, or infection—not epinephrine itself 4, 5
- Over 250,000 procedures on digits have been reported using lidocaine with epinephrine without resulting necrosis 6
A Cochrane systematic review found that epinephrine with lidocaine prolonged anesthesia duration by 3.20 hours (95% CI 2.48-3.92) and significantly reduced bleeding during surgery (risk ratio 0.35,95% CI 0.19-0.65). 7
Patient Selection and Safety Precautions
Patients with stable cardiovascular conditions can safely receive lidocaine with epinephrine. 1, 3
Exercise caution in these specific situations: 3, 6
- Active infection in the digit
- Severe peripheral vascular disease or uncontrolled vasospastic conditions (Raynaud's syndrome)
- Uncontrolled hypertension
- Pregnancy (postpone elective procedures or delay until second trimester)
Have phentolamine available as a rescue medication to reverse potential epinephrine-induced vasoconstriction if needed. 1
Critical Safety Measures
Do not use lidocaine with epinephrine within 4 hours of other local anesthetic interventions to prevent cumulative toxicity. 8, 2, 3
Monitor for early signs of local anesthetic toxicity: 2
- Circumoral numbness
- Facial tingling or flushing
- Metallic taste
- Tinnitus or auditory changes
- Slurred speech
Aspirate before injection and use incremental injections while continuously assessing the patient. 3