What are the uses and dosages of lidocaine (local anesthetic/antiarrhythmic agent)?

Uses and Dosages of Lidocaine

Lidocaine is a versatile local anesthetic and class Ib antiarrhythmic agent with specific dosing requirements that vary by indication, with maximum doses determined by administration route and patient factors to minimize toxicity risk.

Primary Uses

Local Anesthesia

• Lidocaine is widely used as a local anesthetic for various procedures including nerve blocks, infiltration anesthesia, and topical applications 1
• For peripheral nerve blocks, the maximum dose is 7.0 mg/kg when used with epinephrine 1
• For retrobulbar injection, the suggested dose is 3-5 mL (120-200 mg) for a 70 kg person 2
• For transtracheal injection, 2-3 mL should be injected, rarely exceeding 5 mL (200 mg) 2
• For topical application in laryngoscopy, bronchoscopy, and endotracheal intubation, the pharynx may be sprayed with 1-5 mL (40-200 mg) 2

Antiarrhythmic Use

• Lidocaine is used for treatment of ventricular arrhythmias, particularly in the setting of acute myocardial infarction 3, 4
• For cardiac arrest patients with persistent ventricular tachycardia/fibrillation despite defibrillation and epinephrine, lidocaine is recommended as the first antiarrhythmic agent 3
• Initial bolus of 1.0-1.5 mg/kg (75-100 mg), with additional boluses of 0.5-0.75 mg/kg (25-50 mg) every 5-10 minutes if needed, up to a total of 3 mg/kg 3

Postoperative Pain Management

• Intravenous lidocaine infusions are used for postoperative pain management and enhanced recovery 3
• Loading dose should not exceed 1.5 mg/kg, given as an infusion over 10 minutes 3
• Maintenance infusion should not exceed 1.5 mg/kg/h for no longer than 24 hours 3

Dosing Considerations

Weight-Based Dosing

• Ideal body weight should be used for dose calculation, especially for IV administration 3, 1
• For men: ideal body weight = (height in cm - 100) 3
• For women: ideal body weight = (height in cm - 105) 3
• Intravenous lidocaine should not be used in patients weighing less than 40 kg 3
• For any patient, no more than 120 mg/h should be infused when used for postoperative pain 3

Maximum Recommended Doses

• For healthy adults, the maximum dose of lidocaine HCl should be kept below 300 mg and should not exceed 4.5 mg/kg body weight 2
• For children under ten years, the maximum dose may be determined using standard pediatric drug formulas (e.g., Clark's rule) 2
• Doses should be reduced for elderly, debilitated patients, and those with hepatic or cardiovascular disease 2

Safety Considerations

Contraindications and Precautions

• Relative contraindications include: cardiac disease, electrolyte disorders, seizure disorders, renal or hepatic impairment, pregnancy/breastfeeding, and neurological disorders 3
• Lidocaine should be used with caution in patients with impaired cardiovascular function 2
• Since amide-type local anesthetics are metabolized by the liver, lidocaine should be used with caution in patients with hepatic disease 2

Toxicity Prevention

• Careful monitoring is essential when administering lidocaine, particularly during IV infusion 3
• Continuous ECG and pulse oximetry with regular blood pressure monitoring is recommended during initial infusion and for the first 15 minutes thereafter 3
• Early signs of toxicity include: restlessness, anxiety, tinnitus, dizziness, blurred vision, tremors, depression, or drowsiness 2
• Plasma lidocaine concentration correlates with toxic effects, with serious cardiac arrhythmias occurring at higher concentrations 3

Drug Interactions

• Intravenous lidocaine should not be used at the same time as, or within the period of action of, other local anesthetic interventions 3
• No nerve or fascial plane blocks should be performed until 4 hours after completion of an IV lidocaine infusion 3
• Topical 5% lidocaine medicated plasters should be removed before starting an IV lidocaine infusion 3

Administration Guidelines

IV Administration for Pain Management

• A loading dose of no more than 1.5 mg/kg, given as an infusion over 10 minutes is recommended 3
• After the initial loading dose, an infusion of 1.5 mg/kg/h is recommended, subject to review and reassessment 3
• The lidocaine infusion should be delivered through a separate, dedicated cannula 3
• A minimum flow of sodium chloride 0.9% at 10 ml/h should be used to flush in the lidocaine and help reduce tracking up the vein 3

Special Populations

• Doses should be reduced for elderly and debilitated patients, acutely ill patients, and children 2
• For children, the maximum dose of lidocaine hydrochloride should not exceed 7 mg/kg 2
• Patients with severe hepatic disease are at greater risk of developing toxic plasma concentrations due to impaired metabolism 2