What are the contraindications for using Lidocaine (local anesthetic) for Ventricular Tachycardia (VT)?

Contraindications for Lidocaine in Ventricular Tachycardia

The only absolute contraindication to lidocaine for VT is a known hypersensitivity to amide-type local anesthetics. 1

Absolute Contraindication

• Hypersensitivity to amide-type local anesthetics is the sole FDA-listed absolute contraindication for intravenous lidocaine 1

Relative Contraindications and High-Risk Situations Requiring Caution

While not absolute contraindications, the following conditions warrant significant dose reduction or avoidance due to substantially increased toxicity risk:

Advanced Age

• Patients >70 years old have markedly increased risk of lidocaine toxicity and should receive reduced infusion rates 2, 3
• Elderly patients were specifically excluded from prophylactic lidocaine recommendations due to toxicity concerns 2

Cardiac Conditions Requiring Dose Reduction

• Congestive heart failure: Lidocaine half-life increases to >4 hours (versus 1-2 hours normally), requiring significant dose reduction 2, 3
• Cardiogenic shock: Half-life can exceed 20 hours, necessitating major dose reduction; lidocaine is generally poorly tolerated in shock states 2, 3
• Complete heart block: Lidocaine is contraindicated in this setting 4

Hepatic and Renal Dysfunction

• Hepatic dysfunction: Lidocaine is primarily metabolized by the liver, requiring reduced dosing 2, 3
• Severe renal dysfunction: Warrants caution and dose reduction 2

Neurologic Conditions

• Preexisting neurologic dysfunction: Requires caution and reduced infusion rates due to increased risk of CNS toxicity 2

Clinical Context: When Lidocaine Should NOT Be Used

Hemodynamically Stable Monomorphic VT

• Procainamide is superior to lidocaine for stable monomorphic VT, with termination rates of 80% versus 21% 5
• Lidocaine demonstrates poor efficacy (only 8% termination rate) in stable VT not associated with acute MI 6
• Amiodarone is also more effective than lidocaine, with 78% versus 27% immediate termination rates for shock-resistant VT 7

Prophylactic Use

• Prophylactic lidocaine in uncomplicated acute MI is NOT recommended by the American College of Cardiology, as it provides no mortality benefit and may increase risk of asystole 2, 3

Appropriate Use According to Guidelines

Lidocaine should be reserved for:

• Recurrent sustained VT/VF not responding to beta-blockers or amiodarone 3
• VT/VF associated with acute myocardial ischemia or infarction 3
• As an alternative when amiodarone is contraindicated 2, 3

Toxicity Recognition

Monitor closely for CNS and cardiovascular toxicity manifestations 2:

• CNS effects: Nausea, drowsiness, perioral numbness, dizziness, confusion, slurred speech, muscle twitching, respiratory depression, tremor, altered consciousness
• Cardiovascular effects: Bradycardia, sinus arrest, hypotension
• Consider measuring serum levels with prolonged infusions (therapeutic target ≤5 μg/mL) 3