Lidocaine, Xylocaine

Question 1

Lidocaine Class

Answer 1

Antidysrhythmic (Class I-B)

Question 2

Lidocaine Action

Answer 2

• Decreases ventricular automaticity (reduces the slope of
phase 4 diastolic depolarization)
• Decreases excitability, and raises fibrillation threshold
• Decreases conduction in ischemic cardiac tissue without
adversely affecting normal conduction
• Does not affect contractility

Question 3

Lidocaine Indications

Answer 3

• Pulseless VT/VF
• VT w/ pulse
• Malignant PVCs
• Wide complex tachycardias of unknown origin
• Pre-Intubation in the setting of closed head injuries and
strokes

Question 4

Lidocaine Contraindications

Answer 4

• Advanced AV block (2nd degree Type II (Mobitz II) and 3rd degree blocks) in the absence of a functioning pacemaker
• Adams-Stokes syndrome

Question 5

Lidocaine Precautions

Answer 5

• Hypotension

* Torsades de Pointes (if known torsade’s, magnesium is the agent of choice)

Question 6

Lidocaine Dosage

Answer 6

Adults:
• Pulseless VT/VF: IV/IO: 1-1.5 mg/kg IV, can repeat in 3-5 min not to exceed 3 mg/kg or 300 mg in 30 minutes.
• Stable VT: 1-1.5 mg/kg slow IV bolus followed by additional doses of 0.5-0.75 mg/kg q 5 min not to exceed 3 mg/kg or 300 mg in 30 minutes.
• Infusion: 1-4 mg/minute titrated for effect.
Pediatrics:
• All Ventricular dysrhythmias: IV/IO: 1 mg/kg bolus, not to exceed 3 mg/kg
• Continuous Infusion: IV/IO: 20-50 µg/kg/min infusion. 120 mg in 100 ml NS yielding 1.2 mg/ml.

Question 7

Lidocaine Onst/ Duration

Answer 7

• Onset: IV—30-90 sec

* Duration: IV—10-20 min for bolus

Question 8

Lidocaine Side Effects

Answer 8

• Drowsiness
• Dizziness
• Confusion
• Slurred speech
• Seizures
• Respiratory depression/arrest
• Hypotension
• Dysrhythmias
• Bradycardia
• Cardiac arrest
• N/V

Question 9

Lidocaine Interactions

Answer 9

Additive cardiac depression and toxicity when used
concomitantly with: 
• Amiodarone
•Procainamide
• Phenytoin,
• Quinidine
• BB