What is the administration time for the initial 100mg bolus of lidocaine and its repeat protocol in cardiac arrest, and when is it preferred over amiodarone and dose reduced?

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Last updated: June 14, 2025View editorial policy

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From the Guidelines

Lidocaine in cardiac arrest is administered as an initial 1.0 to 1.5 mg/kg IV bolus over 1-2 minutes, with a repeat dose of 0.5 to 0.75 mg/kg IV push allowed after 5-10 minutes if needed, not exceeding a total dose of 3 mg/kg.

Administration and Dosage

  • The initial dose of lidocaine is 1.0 to 1.5 mg/kg IV, which can be approximated to a 100mg bolus for a typical adult patient [ 1 ].
  • The repeat dose is 0.5 to 0.75 mg/kg IV push, administered at 5- to 10-minute intervals [ 1 ].
  • The maximum total dose should not exceed 3 mg/kg.

Preference Over Amiodarone

  • Lidocaine is preferred over amiodarone in situations where amiodarone is contraindicated or unavailable [ 1 ].
  • Additionally, lidocaine may be considered in patients with liver failure or hypotension, as it has fewer immediate side effects compared to amiodarone.

Dose Reduction

  • The dose of lidocaine should be reduced in patients with hepatic impairment, heart failure, shock, or those over 70 years old [ 1 ].
  • A 50% reduction in dose is recommended for these patients, with a maximum total dose of 200-300mg.

Monitoring and Side Effects

  • Patients receiving lidocaine should be monitored for CNS toxicity (confusion, seizures) and cardiovascular side effects (hypotension, bradycardia), especially in those with reduced clearance [ 1 ].
  • Lidocaine works by stabilizing cardiac cell membranes through sodium channel blockade, which suppresses ventricular arrhythmias, making it particularly useful for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia after defibrillation attempts.

From the Research

Administration Time and Repeat Protocol for Lidocaine in Cardiac Arrest

  • The administration time for the initial 100mg bolus of lidocaine is not explicitly stated in the provided studies, but it is generally administered over 1-2 minutes 2, 3.
  • If there is a return of spontaneous circulation, the infusion can be set up, but the specific details of the infusion protocol are not provided in the studies.
  • The bolus can be repeated after 10-15 minutes if necessary, but again, the exact repeat protocol is not specified in the studies.

Preference of Lidocaine over Amiodarone in Cardiac Arrest

  • Lidocaine may be preferred over amiodarone in certain situations, such as in patients with witnessed cardiac arrest or in those with a higher likelihood of return of spontaneous circulation 4, 5.
  • Lidocaine has been shown to be associated with higher rates of return of spontaneous circulation, 24-hour survival, survival to hospital discharge, and favorable neurologic outcome compared to amiodarone in some studies 4.

Dose Reduction for Lidocaine

  • The dose of lidocaine may need to be reduced in certain situations, such as in patients with impaired liver function or in those with a history of seizures 3.
  • However, the specific guidelines for dose reduction are not provided in the studies, and the initial dose of 100mg is generally recommended for most patients.

Situations Where Lidocaine is Preferred

  • Lidocaine may be preferred in situations where the cardiac arrest is caused by ventricular fibrillation or pulseless ventricular tachycardia, and the patient has a higher likelihood of return of spontaneous circulation 5, 6.
  • Early administration of lidocaine, particularly prior to the second defibrillator shock, may be associated with an increased odds of survival outcomes in in-hospital cardiac arrest with shockable rhythms 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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