Lidocaine Pharmacology

The Effects of Lidocaine:

Lidocaine causes negative inotropic effects and antiarrhythmic actions in the heart that weaken the force of muscular contractions. Lidocaine can calm erratic and uncoordinated electro-myocardial activity.

Indications for Use of Lidocaine:

Due to lidocaine’s antiarrhythmic properties, its primary use is for:

Lidocaine is also effective in treating:

  • Stable monomorphic ventricular tachycardia with preserved ventricular function
  • Stable polymorphic ventricular tachycardia with normal baseline
  • QT interval and preserved lower ventricular function when ischemia is treated and electrolyte balance is corrected
  • Stable polymorphic ventricular tachycardia with baseline and QT interval prolongation when Torsades de pointes is suspected

Lidocaine Precautions & Contraindications:

Lidocaine should not be used as a prophylactic treatment in acute myocardial infarction.

The maintenance dose should be reduced in the presence of impaired liver function or lower ventricular dysfunction.  Infusion should be discontinued immediately if signs of toxicity develop.

Lidocaine would be contraindicated if there is a known hypersensitivity to lidocaine or derivatives like xylocaine, novocaine, etc.

Lidocaine is also contraindicated in sinus bradycardia and atrioventricular blocks.

Adult Dosage for Lidocaine:

Dosage for cardiac arrest from ventricular fibrillation or pulseless ventricular tachycardia:

  • Initial dose is 1 to 1.5 mg/kg IV or IO
  • Can also be delivered via endotracheal tube

Dosage for refractory ventricular fibrillation:

  • An additional .5 to .75 mg/kg may be given via IV push
  • This can be repeated in 5 to 10 minutes to a maximum of 3 doses or a total of 3 mg/kg

Dosage used for perfusing arrhythmias, like stable ventricular tachycardia, wide-complex tachycardia, or an uncertain type or significant ectopy:

  • Doses range from .5 to .75 mg/kg and up to 1 to 1.5 mg/kg
  • This can also be repeated at .5 to .75 mg/kg every 5 to 10 minutes to a maximum total dose of 3 mg/kg
  • For a maintenance infusion, 1 to 4 mg per minute should be given, which is equal to 30- 50 mcg/kg per minute
  • A microdrip infusion set is needed in order to deliver the appropriate dose

A common calculation for mixing a lidocaine drip is:

(IV Bag Amount in mL)  X (Dose Ordered (mg/min))  X (Drip Set (gtts/mL)
Divided by
(Drug on Hand in mg)
= Correct drops per minute