What is the recommended dose of lidocaine (local anesthetic) for a 65-pound patient?

Lidocaine Dosing for a 65-Pound Patient

For a 65-pound (29.5 kg) patient, the recommended lidocaine dose without epinephrine should not exceed 132.75 mg (4.5 mg/kg), and with epinephrine should not exceed 206.5 mg (7 mg/kg). 1, 2

Dosing Calculations

• Calculate the maximum safe dose based on the patient's weight:
  • Without epinephrine: 4.5 mg/kg × 29.5 kg = 132.75 mg maximum 1
  • With epinephrine: 7 mg/kg × 29.5 kg = 206.5 mg maximum 2
• For pediatric patients, dosing should be calculated based on weight, with the maximum dose for a child weighing 50 lbs (similar to our 65 lb patient) not exceeding 75-100 mg (1.5-2 mg/kg) 1
• Ideal body weight should be used for dose calculations rather than actual body weight 3, 4

Administration Guidelines

• For intravenous administration, use a loading dose of no more than 1.5 mg/kg (44.25 mg for this patient), given as an infusion over 10 minutes 3, 4
• For maintenance infusion, do not exceed 1.5 mg/kg/h and limit to no more than 24 hours 3
• Regardless of weight, do not exceed 120 mg/hour for any patient 4
• For local anesthetic injection, the lowest effective concentration and dose should be used to guard against systemic toxicity 1

Safety Considerations

• Monitor for signs of local anesthetic toxicity, including:
  • Early signs: tingling of tongue/lips, light-headedness, tinnitus, slurred speech 4, 2
  • Progressive signs: muscle twitching, loss of consciousness, respiratory arrest 4, 2
• Do not use lidocaine within 4 hours of other local anesthetic interventions 3, 4, 2
• Remove any topical lidocaine preparations before starting intravenous lidocaine 4, 2
• Be especially cautious with lidocaine in patients with electrolyte disorders, seizure disorders, renal or hepatic impairment, or neurological disorders 4, 2

Important Cautions

• Lidocaine should not be used in patients weighing less than 40 kg for intravenous infusion, but can be used for local anesthesia with appropriate weight-based dosing 3, 4
• Significant interindividual differences in lidocaine absorption and metabolism can occur, leading to unpredictably high absorption levels in some individuals 5
• Deaths from lidocaine-induced local anesthetic systemic toxicity remain a concern, highlighting the importance of careful dosing and monitoring 6

Remember that the formulation and concentration of lidocaine, as well as individual patient factors, can significantly affect serum levels and efficacy 5.