Basics

Lidocaine is a drug belonging to the class of local anesthetics. In addition to its use as a local anesthetic, lidocaine is used in some cases as a class Ib antiarrhythmic agent. Since its development in the 1940s, it has been one of the most widely used drugs in the world. For example, it is used for anesthesia during minor surgical procedures. Lidocaine is also on the WHO's list of essential medicines.

Lidocaine is usually administered in the form of injections (infiltration anaesthesia) or as a spray or ointment (surface anaesthesia). When used as an antiarrhythmic agent, it is administered exclusively intravenously.

Pharmacology

Pharmacodynamics

The effect of the substance is based on the blockade of voltage-dependent sodium channels located in the membranes of nerve cells. Sodium channels are significantly involved in the transmission of stimuli in the human body. If they are blocked at certain points in the body, no stimuli (e.g. pain) are transmitted from there to the brain. This is the reason for the local anaesthesia of Lidocaine. The antiarrhythmic effect is based on the same principle. Here, however, sodium channels in the heart muscle cells are blocked. This results in a prolongation of the action potential, whereby certain arrhythmias can be remedied. However, lidocaine itself can also cause arrhythmias, which is why it is now rarely considered for this application.

Pharmacokinetics

Lidocaine is well absorbed in the GI tract, but a large portion of the given dose is immediately cleared due to the significant "first pass effect," which is why oral bioavailability is only 35%. Therefore, lidocaine for systemic use (antiarrhythmic) is administered intravenously only. This circumvents the "first pass effect". Lidocaine is 60-80% bound to plasma proteins and is relatively rapidly cleared by the liver. The elimination half-life is 1.5-2 hours. The majority of the given dose is excreted via the kidneys.

Drug Interactions

Drug interactions are not expected when used as a topical anesthetic. When used as an antiarrhythmic agent, class III antiarrhythmic agents should not be given concomitantly under any circumstances.

Toxicity

Typical side effects (common and very common)

Hypotension
Nausea
Paresthesia
Dizziness
Bradycardia
Hypertension
Vomiting

Toxicological data

LD50 (rat, oral): 317 mg-kg-1

Author

Markus Falkenstätter, BSc

Pharmacy student

Markus Falkenstätter is a writer on pharmaceutical topics in Medikamio's medical editorial team. He is in the last semester of his pharmacy studies at the University of Vienna and loves scientific work in the field of natural sciences.

Reviewer

Mag. pharm. Stefanie Brandauer

Pharmacist

Stefanie Lehenauer has been a freelance writer for Medikamio since 2020 and studied pharmacy at the University of Vienna. She works as a pharmacist in Vienna and her passion is herbal medicines and their effects.

Editorial principles

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