What are the guidelines for administering Intravenous (IV) lidocaine (lidocaine)?

Intravenous Lidocaine Administration Guidelines

Dosing Protocol

For IV lidocaine administration, give a loading dose of 1.5 mg/kg over 10 minutes, followed by a continuous infusion at 1.5 mg/kg/hour, with duration not exceeding 24 hours in most cases. 1

Loading Dose

• Maximum loading dose: 1.5 mg/kg infused over 10 minutes 1
• Calculate using ideal body weight (IBW): Men = height in cm - 100; Women = height in cm - 105 2
• Do not use in patients weighing less than 40 kg 2
• Too rapid infusion increases toxicity risk 1
• Complete the initial infusion before skin incision when possible 1

Maintenance Infusion

• Standard rate: 1.5 mg/kg/hour 1
• Maximum hourly dose: 120 mg/hour regardless of weight 2
• This dosing typically maintains plasma concentrations below 5 μg/mL 1
• Only consultant anaesthetists or intensivists should alter infusion rates 1
• Frequent rate changes should be discouraged 1

Duration

• Do not exceed 24 hours in most patients 1
• If extension beyond 24 hours is necessary, reduce infusion rate to 50% 1
• Decision to extend must be made by consultant anaesthetist/intensivist or acute pain team 1
• Note that lidocaine exhibits time-dependent pharmacokinetics, with half-life prolonging from 100 minutes to 3.22 hours after 24 hours of infusion 3

Administration Technique

Equipment Requirements

• Use dedicated, labelled, lockable, tamperproof infusion pumps with fixed rate and upper rate limits 1
• Pumps must have anti-siphon and anti-reflux mechanisms 1
• Use commercially prepared syringes/bags when available to reduce concentration errors 1
• Maintain standard concentration throughout the hospital per protocol 1

IV Access and Line Management

• Deliver through a separate, dedicated cannula 1, 2
• Co-infuse minimum 10 mL/hour sodium chloride 0.9% from dedicated bag to flush lidocaine and reduce vein tracking 1
• Line must have one-way valve to prevent retrograde tracking into other infusions 1
• Label infusion line with ISO-standard grey 'lidocaine' label 1
• Maintain separate lidocaine monitoring chart 1

Monitoring Requirements

Initial Monitoring (Operating Theatre/Recovery)

• Anaesthetist must be present during initial dose 1
• Continuous ECG and pulse oximetry throughout 1
• Blood pressure every 5 minutes during initial infusion and first 15 minutes thereafter 1, 2

Post-Operative Monitoring

• Ideally manage in high dependency unit (level 2 care) 1
• Observations every 15 minutes for first hour, then hourly minimum 1
• Continue ECG monitoring (though cardiovascular changes are late signs) 1
• Nurses must be trained in toxicity recognition 1
• Acute pain team should be involved in monitoring and follow-up 1

Toxicity Recognition and Management

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

• Neurological symptoms appear first: peri-oral tingling, tinnitus, light-headedness, restlessness 1
• Circumoral numbness, facial tingling, slurred speech 4, 2
• Tingling of tongue/lips 4, 2

Severe Toxicity Signs (Plasma >10 μg/mL)

• Muscle twitching, loss of consciousness 1, 4
• Respiratory arrest 1, 4
• Cardiac arrhythmias, myocardial depression 1, 4
• Ventricular arrest 4, 2

Emergency Preparedness

• Lipid emulsion 20% must be readily available wherever IV lidocaine is used 1
• Staff must know storage location 1
• Follow Association of Anaesthetists' management guideline for treatment 1
• Discontinue all lidocaine immediately if toxicity signs appear 4, 2

Drug Interactions and Contraindications

Local Anesthetic Interactions

• Remove topical 5% lidocaine plasters before starting IV infusion 1, 2
• No nerve or fascial plane blocks until 4 hours after completing IV lidocaine 1, 2
• No boluses into wound/epidural catheters until 4 hours after completion 1
• Infusions (without boluses) through wound/epidural catheters may start 30 minutes after stopping IV lidocaine 1
• Single-shot spinal blockade is acceptable due to small local anesthetic dose 1, 2
• Intrathecal opioids can be used concurrently 1

Concurrent Medications

• Concurrent ketamine administration is acceptable 1
• Ketamine is often tried before lidocaine in difficult-to-manage pain 1

High-Risk Populations (Use with Caution)

• Cardiac disease, electrolyte disorders 4, 2
• Seizure disorders 4, 2
• Renal or hepatic impairment 4, 2
• Pregnancy/breastfeeding 4, 2
• Neurological disorders 4, 2
• Advanced liver failure (contraindicated due to decreased clearance) 4

Critical Safety Considerations

Common Pitfalls to Avoid

• Never calculate dose using actual body weight in obese patients—use ideal body weight 2
• Never combine with other local anesthetics without appropriate waiting periods 1, 2
• Never assume cardiovascular signs will appear before neurological signs—they are late manifestations 1
• Never extend infusion beyond 24 hours without consultant approval and rate reduction 1
• Particular vigilance needed in patients with existing comorbidity 1

Incident Management

• Preserve pump with settings and memory intact if adverse incident occurs 1
• Consider toxicity possibility even when other explanations exist for clinical presentation 1