ACLS/BLS Tips: Lidocaine

Quick Info 

Indications: 

• Alternative to amiodarone in cardiac arrest from VF/pVT

• Stable monomorphic VT with preserved ventricular function

• Stable polymorphic VT with normal baseline QT interval and preserved LV function when ischemia is treated and electrolyte balance is corrected

Dose: 

• Initial dose: 1 - 1.5 mg/kg IV/IO

• For refractory VF, may give additional dose(s) of 0.5 - 0.75 mg/kg IV/IO every 5-10 min until maximum dose for 3 mg/kg

Contraindications/Cautions: 

• Contraindication: Prophylactic use in AMI

• Reduce maintenance dose (not loading dose) in presence of impaired liver function or LV dysfunction

• Discontinue infusion immediately if signs of toxicity develop

Overview

Lidocaine is a common drug used within ACLS in the management of cardiac arrest. It’s a class Ib antiarrhythmic that blocks fast sodium channels, preferentially in ischemic or depolarized ventricular tissue. It works by reducing automaticity and shortening the action potential duration, helping terminate ventricular fibrillation/pulseless VT (VF/pVT). In ACLS, lidocaine is an alternative to amiodarone for shock-refractory VF/pVT (Class 2b: may be considered). Typical dosing: 1–1.5 mg/kg IV/IO, then 0.5–0.75 mg/kg every 5–10 min (max 3 mg/kg); consider an infusion (e.g., 1–4 mg/min) within ROSC for ongoing ectopy.    

The ALPS RCT (NEJM 2016) found neither amiodarone nor lidocaine improved survival to discharge or favorable neurologic outcome versus placebo overall; however, a prespecified subgroup with witnessed out-of-hospital arrests showed higher survival with either drug versus placebo. Subsequent guidance from ILCOR/AHA reflects this nuance—antiarrhythmics may improve short-term outcomes (e.g., ROSC) and possibly benefit witnessed arrests, but do not clearly improve ultimate survival or neurologic recovery. Recent consensus updates (2023–2024) maintain a cautious, optional role for lidocaine or amiodarone in shock-refractory VF/pVT.     

Lidocaine should be avoided in severe SA/AV block without pacing. Dosing should also be reduced in hepatic impairment, low body weight, or older adults. Be cautious during its administration and watch for hypotension, bradycardia, and CNS toxicity (paresthesias, confusion, seizures). Post-ROSC infusions should be individualized and reassessed as acidosis, temperature, and hemodynamics evolve. As always, prioritize early high-quality CPR, defibrillation for shockable rhythms, and timely epinephrine; antiarrhythmics are adjuncts and not substitutes for these fundamentals. 

ACLS Tips: 

• During the cardiac arrest algorithm be cognizant of what arm of the algorithm you’re on. It’s easy to forget Amio or Lido if you’ve been managing PEA/Asystole for some time and then find your patient is now in a VF/pVT. 

• An easy way to remember the repeat dose of the lidocaine is that it’s half of what you initially gave. 

References:

Dorian, P., Cass, D., Schwartz, B., Cooper, R., Gelaznikas, R., & Barr, A. (2002). Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. New England Journal of Medicine, 346(12), 884–890. https://doi.org/10.1056/NEJMoa013029

Heart & Stroke Foundation of Canada. (2020). Advanced Cardiac Life Support. Canada.

Kudenchuk, P. J., Brown, S. P., Daya, M., Rea, T., Nichol, G., Morrison, L. J., … Dorian, P., & the Resuscitation Outcomes Consortium Investigators. (2016). Amiodarone, lidocaine, or placebo in out-of-hospital cardiac arrest. New England Journal of Medicine, 375(8), 802–813. https://doi.org/10.1056/NEJMoa1514204

Kudenchuk, P. J. (2017). Antiarrhythmic drugs for nonshockable-turned-shockable out-of-hospital cardiac arrest. Circulation, 135(4), e433–e434. https://doi.org/10.1161/CIRCULATIONAHA.117.028624