Systemic Monograph Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type.

Longer-acting substances such as bupivacaine are sometimes given preference for spinal and epidural anaesthesias; lidocaine, though, has the advantage of a rapid onset of action.

It can be administered in multiple ways, most often as a nerve block or infiltration, depending on the type of treatment carried out and the area of the mouth worked on.

[19] An adhesive transdermal patch containing a 5% concentration of lidocaine in a hydrogel bandage, is approved by the US FDA for reducing nerve pain caused by shingles.

Lidocaine is a common class-1b antiarrhythmic drug; it is used intravenously for the treatment of ventricular arrhythmias (for acute myocardial infarction, digoxin poisoning, cardioversion, or cardiac catheterization) if amiodarone is not available or contraindicated.

This application can be implemented as a safety and comfort measure for people needing intubation, as it reduces the incidence of coughing and any tracheal damage it might cause when emerging from anaesthesia.

[24] A 2019 systematic review of the literature found that intraurethral lidocaine reduces pain in men who undergo cystoscopic procedures.

[25] Lidocaine, along with ethanol, ammonia, and acetic acid, may also help in treating jellyfish stings, both numbing the affected area and preventing further nematocyst discharge.

[28] A 2021 study found that lidocaine 5% spray on glans penis 10-20 minutes prior to sexual intercourse significantly improves premature ejaculation.

[29] Another study found that lidocaine-prilocaine cream 5% is effective in premature ejaculation and 20 minutes of application time before sexual intercourse.

Common ADRs include headache, dizziness, drowsiness, confusion, visual disturbances, tinnitus, tremor, and/or paraesthesia.

Infrequent ADRs associated with the use of lidocaine include: hypotension, bradycardia, arrhythmias, cardiac arrest, muscle twitching, seizures, coma, and/or respiratory depression.

[33] The use of lidocaine for spinal anesthesia may lead to an increased risk of transient neurological symptoms, a painful condition that is sometimes experienced immediately after surgery.

[34] There is some weak evidence to suggest that the use of alternative anesthetic medications such as prilocaine, procaine, bupivacaine, ropivacaine, or levobupivacaine may decrease the risk of a person developing transient neurological symptoms.

[34] Low-quality evidence suggests that 2‐chloroprocaine and mepivacaine when used for spinal anesthetic have a similar risk of the person developing transient neurological symptoms as lidocaine.

Dronedarone and liposomal morphine are both absolutely a contraindication, as they may increase the serum levels, but hundreds of other drugs require monitoring for interaction.

[35] Absolute contraindications for the use of lidocaine include: Exercise caution in people with any of these: Overdoses of lidocaine may result from excessive administration by topical or parenteral routes, accidental oral ingestion of topical preparations by children (who are more susceptible to overdose), accidental intravenous (rather than subcutaneous, intrathecal, or paracervical) injection, or from prolonged use of subcutaneous infiltration anesthesia during cosmetic surgery.

[43] Lidocaine and its two major metabolites may be quantified in blood, plasma, or serum to confirm the diagnosis in potential poisoning victims or to assist forensic investigation in a case of fatal overdose.

[44] Treatment with intravenous lipid emulsions (used for parenteral feeding) to reverse the effects of local anaesthetic toxicity is becoming more common.

[9][10] Lidocaine is about 95% metabolized (dealkylated) in the liver mainly by CYP3A4 to the pharmacologically active metabolites monoethylglycinexylidide (MEGX) and then subsequently to the inactive glycine xylidide.

In addition to this aromatic unit, lidocaine has an aliphatic section comprising amide, carbonyl, and enyl groups.

The dynamic transformation of lidocaine conformers in supercritical carbon dioxide (scCO2) highly depends on external factors such as pressure[53] and temperature.

Changes in the position of the amide group within the molecule can trigger a redistribution of intra- and intermolecular hydrogen bonds, affecting the outcome of the micronization process and the resultant particle size.