What is the recommended pre‑operative dose of Loxicard 2% (lidocaine) for an adult patient, including maximum single‑dose limits with and without epinephrine and any adjustments for hepatic dysfunction or lidocaine sensitivity?

Loxicard 2% Pre-operative Dosing

For pre-operative local infiltration in adults, administer no more than 4.5 mg/kg of lidocaine 2% (Loxicard) without epinephrine, or up to 7.0 mg/kg when combined with epinephrine, using ideal body weight for calculations in patients with BMI >30 kg/m². 1, 2

Maximum Dose Calculations

Standard Adult Dosing

• Without epinephrine: Maximum 4.5 mg/kg (typically 300-315 mg for a 70 kg patient) 1, 2
• With epinephrine: Maximum 7.0 mg/kg (typically 490 mg for a 70 kg patient) 1, 2
• For Loxicard 2% solution: Each mL contains 20 mg of lidocaine 1
  • Without epinephrine: Maximum ~15-16 mL for 70 kg patient
  • With epinephrine: Maximum ~24-25 mL for 70 kg patient

Special Populations Requiring Dose Reduction

Hepatic Dysfunction: Use extreme caution and reduce doses significantly, as lidocaine is contraindicated in advanced liver failure due to decreased hepatic clearance and prolonged elimination 2, 3, 4

Body Weight Considerations:

• Use ideal body weight (not actual weight) for dose calculations in obese patients (BMI >30 kg/m²) 2, 5
• Avoid or use extreme caution in patients weighing <40 kg 2, 6

Elderly Patients (>70 years): Reduce doses due to increased risk of toxicity from altered pharmacokinetics 2, 3

Cardiac Disease: Use with extreme caution and consider dose reduction, as cardiac failure decreases lidocaine clearance and increases risk of accumulation 6, 3, 4

Critical Safety Precautions

Cumulative Dosing

• Never administer lidocaine within 4 hours of any other local anesthetic intervention to prevent cumulative toxicity 2, 7, 6
• Calculate the total dose of ALL local anesthetics administered (topical, infiltrative, regional blocks) when determining maximum safe dosage 2
• Remove any topical 5% lidocaine patches before administering injectable lidocaine 2

Administration Technique to Minimize Toxicity Risk

• Always aspirate before each injection to avoid intravascular administration 1
• Use incremental injections rather than bolus administration 1
• Inject slowly with small-caliber needles 7
• Consider buffering with bicarbonate and warming to body temperature to reduce injection pain 7

Monitoring for Toxicity

Early Warning Signs (Plasma levels 5-10 μg/mL)

Monitor continuously during and after injection for: 2, 6

• Circumoral numbness
• Facial or tongue tingling
• Tinnitus (ringing in ears)
• Light-headedness or dizziness
• Slurred speech

Severe Toxicity Signs (Plasma levels >10 μg/mL)

2, 6

• Muscle twitching or tremor
• Seizures or convulsions
• Loss of consciousness
• Respiratory arrest
• Cardiac arrhythmias or cardiovascular collapse

If any signs of toxicity appear, discontinue lidocaine immediately and initiate emergency protocols with 20% lipid emulsion available for treatment. 2, 6

Alternative Dosing for Specific Surgical Contexts

Intravenous Lidocaine for Major Surgery

For adults undergoing major abdominal, pelvic, or spinal surgery without regional analgesia: 1

• Bolus: 1-2 mg/kg IV over 20 minutes at induction
• Infusion: 1-2 mg/kg/hour continuous infusion
• This provides analgesic, anti-hyperalgesic, and anti-inflammatory effects

Multi-stage Procedures (e.g., Mohs Surgery)

For procedures requiring multiple injections over several hours, a maximum cumulative dose of 500 mg of 1% lidocaine solution (50 mL) delivered incrementally is recommended 1

Absolute Contraindications

2, 7

• Known allergy to amide-type local anesthetics
• Advanced liver failure
• Grossly contaminated wounds (for topical applications)
• Recent administration (<4 hours) of other local anesthetics