Lidocaine

See critical care quick reference for drug doses by weight.

General

• Also known internationally as lignocaine
• Type: Local anesthetics; Antiarrhythmics
• Dosage Forms: Local injection, transdermal, intravenous, inhaled, viscous
• Common Trade Names: Xylocaine, P-Care, ReadySharp Lidocaine, Xylocard

Adult Dosing

Local Anesthetic

• Maximum without epinepherine: 5mg/kg (max 300mg)
• Maximum with epinepherine: 7mg/kg (max 500mg)

Antiarrhythmic

• Loading dose = 1-1.5mg/kg
  • Additional boluses of 0.5-0.75mg/kg q5-10min up to max of 3mg/kg
  • If effective start infusion of 2mg/min
• Indications
  • Treatment of ventricular arrhythmias and ectopy
    • Considered 2nd-line to amiodarone for treatment of V-fib and pulseless v-tach

Pediatric Dosing

Local Anesthetic

• Without epinepherine: 5mg/kg (max 300mg)
• With epinepherine: 7mg/kg (max 500mg)

Antiarrhythmic

See critical care quick reference for drug doses by weight.

Special Populations

• Pregnancy Rating: American B, Australia A
• Lactation: Not expected to cause any adverse effect
• Renal Dosing
  • Adult: No adjustment provided in manufacturer's labelling but accumulation of metabolites may be increased in renal dysfunction
  • Pediatric: No adjustment provided in manufacturer's labelling
• Hepatic Dosing
  • Adult: Reduce maintenance infusion when used IV (0.75 mg/minute). Monitor concentration.
  • Pediatric: Use with caution. Reduce dose.

Contraindications

• Allergy to class/drug or agents with same chemical classification (amide/ester)
• High SA or AV block

Adverse Reactions

Serious

• Local Anesthetic Systemic Toxicity (LAST)
  • Rare during infiltration of local anesthetic
  • CNS toxicity
    • Metallic taste, tinnitus, tingling of lips, dizziness, anxiety, confusion, lethargy, loss of consciousness, seizures
  • Cardiovascular toxicity
    • Bradycardia, decreased myocardial contractility, atrioventricular block, vasodilation, ventricular arrhythmias, cardiac arrest

Pharmacology

• Half-life:
  • Onset of action = 45-90s
  • Duration of action = 10-20min (antiarrythmic IV); 30-90 min (subcutaneous)
• Metabolism:
• Excretion:
• Mechanism of Action:
  • Class Ib antiarrythmic
    • Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization
    • Acts preferentially on ischemic tissue
      • Elevates V-fib threshold
      • Suppresses ventricular ectopy
  • Little effect on vascular tone, contractility or cardiac output

Comments

• For wounds, may use HCO3 (1cc to 10cc Lido) to decrease pain
• Inject through wound edges NOT intact skin

See Also

• Local anesthetic systemic toxicity
• Critical care quick reference