What is the proper technique for administering a lidocaine (local anesthetic) injection?

From the Guidelines

To administer a lidocaine injection, first verify the correct concentration (typically 1% or 2%) and calculate the appropriate dose based on patient weight (maximum 4.5 mg/kg without epinephrine or 7 mg/kg with epinephrine) as recommended by the guidelines for the use of local anesthesia in office-based dermatologic surgery 1.

Key Considerations

• Prepare the injection site by cleaning with an alcohol swab using circular motions from center outward.
• Draw up the calculated amount of lidocaine into a syringe with an appropriately sized needle (typically 25-30 gauge).
• Before injecting, aspirate by pulling back slightly on the plunger to ensure you're not in a blood vessel.
• Inject the lidocaine slowly at a rate of approximately 1 mL per 10 seconds to minimize pain.

Mechanism of Action and Monitoring

• Lidocaine works by blocking sodium channels in nerve membranes, preventing the generation and conduction of nerve impulses.
• The onset of action is typically within 2-5 minutes, and the duration is about 1-2 hours.
• Always monitor the patient for signs of lidocaine toxicity including dizziness, tinnitus, metallic taste, seizures, or cardiovascular effects.

Additional Recommendations

• For adults, no more than 4.5 mg/kg of lidocaine and 7.0 mg/kg of lidocaine with epinephrine should be administered in a single treatment 1.
• For children, no more than 1.5-2.0 mg/kg of lidocaine and 3.0-4.5 mg/kg of lidocaine with epinephrine should be administered in a single treatment 1.
• Consider alternative forms of local infiltration anesthesia, such as ester-type local anesthetics, bacteriostatic normal saline, or 1% diphenhydramine, for patients with true allergy to lidocaine 1.

From the FDA Drug Label

The safety and effectiveness of lidocaine HCl depend on proper dosage, correct technique, adequate precautions, and readiness for emergencies. Standard textbooks should be consulted for specific techniques and precautions for various regional anesthetic procedures Syringe aspirations should also be performed before and during each supplemental injection when using indwelling catheter techniques An intravascular injection is still possible even if aspirations for blood are negative.

The proper technique for administering a lidocaine injection includes:

• Consulting standard textbooks for specific techniques and precautions for various regional anesthetic procedures 2
• Performing syringe aspirations before and during each supplemental injection when using indwelling catheter techniques 2
• Being aware that an intravascular injection is still possible even if aspirations for blood are negative 2 Correct technique is crucial for the safe and effective use of lidocaine HCl 2. Proper dosage and adequate precautions are also essential 2. Additionally, lidocaine HCl injections are indicated for production of local anesthesia by infiltration techniques and peripheral nerve block techniques when accepted procedures are observed 3.

From the Research

Administration Techniques

• The proper technique for administering a lidocaine (local anesthetic) injection involves using lidocaine 1% with epinephrine 1:200,000, with a maximum dose of 40mL 4.
• Epinephrine should be avoided in certain areas, such as the fingers, toes, and penis 4.
• Injection pain can be reduced by buffering the solution using sodium bicarbonate or by diluting the anesthetic with normal saline in a 1:10 ratio 4, 5.
• Diluting lidocaine with water in a 1:3 ratio has also been shown to have less injection pain and be more effective than unaltered 1% lidocaine 6.

Concentrations and Dilutions

• A concentration of 0.2% to 0.25% lidocaine in water is considered to be the most effective for trigger-point injection in chronic myofascial pain syndrome 6.
• Diluting lidocaine with normal saline in a 1:10 ratio has been shown to be superior to buffered lidocaine for subcutaneous infiltration 5.
• The use of 0.5% lidocaine solutions has been found to have the least injection pain 4.

Special Considerations

• Patients with certain medical conditions, such as those taking tricyclic antidepressants or nonselective beta-blockers, may be at risk for drug interactions with epinephrine 4.
• Aspirin-induced inhibition of platelet adhesion can result in bleeding complications in approximately 15% of skin surgery patients receiving aspirin, and should be stopped at least 7 days prior to surgery in high-risk patients 4.