Description

Lidocaine can be used for surface anesthesia in concentrations up to 10% because it is efficiently absorbed from mucous membranes. Solutions should typically not have a strength greater than 1%, except for surface anesthesia and dental anesthesia. The duration of the block with adrenaline is about 90 minutes.

Lidocaine hydrochloride injection 2% must be shielded from light and kept at a temperature below 25°C. The injection formulation has a 36-month shelf life. It is kept in a flip-top vial and intended for single use.

Therapeutic Indications

Lidocaine Hydrochloride injection USP is indicated for use as infiltration anesthesia, according to the patient’s weight and nature of the procedure. It is widely used in dental procedures; it is most often used in combination with adrenaline (epinephrine).

It is also indicated for use in surface anesthesia, regional anesthesia, and nerve blocks.

Other lidocaine non-injectable formulations may also be used for other purposes. It is also prescribed as an antiarrhythmic drug in dose ventricular arrhythmia. It stabilizes the membrane.

Lidocaine is also used for tonometry in eye drops. Various lidocaine injections with adrenaline are available for dental cartridges. The lidocaine injection is available for use in 5mg (0.5%), 10mg (1%), and 20mg (2%) dosage strength, however, this dose may not be true for certain cases so expert advice should be sought. To avoid excessive dosage in obese patients, the dose may not be calculated based on ideal body weight.

Contraindications

Lidocaine injection is particularly contraindicated in known allergy or hypersensitivity to it or other amide-type anesthetics. When used for atrioventricular arrhythmia it is contraindicated in sino-atrial disorders, myocardial depression, and all grades of atrioventricular block.

When used as local anesthesia it is contraindicated in case of complete heart block and hypovolaemia. Lidocaine Hydrochloride injection 2% is contraindicated for intraocular use. It should also not be injected into infected tissues, or in tissues with inflammation. It is also contraindicated for use on damaged skin.

In such cases, it can have increased absorption into the blood thus leading to systemic side effects with reduced local anesthetic effects. Lidocaine is also contraindicated for use in hepatic impairment, renal impairment, pregnancy, and breastfeeding.

Other Pharmacokinetic properties

The concentration involves lidocaine hydrochloride 2%, or 20 mg/ml in 1ml water for injection. The excipients are water for injection, 1N hydrochloric acid in an adequate quantity and 1N sodium hydroxide with a maximum permissible concentration of 1%.

Lidocaine absorbs directly from the injection site. Following the absorption, it binds to plasma proteins; alpha-1-acid glycoprotein. Through N-dealkylation, the drug is metabolized in the liver to create monoethylglycinexylidide.

Less than 10% of the drug is excreted unchanged in the urine, while more than 90% is metabolized in the liver. Site of administration and tissue vascularity are the two factors that determine the rate of absorption.

The medication is not advised during pregnancy because it can cross the placental and blood-brain barriers. The elimination half-life following IV bolus dose is about 1-2 hours for lidocaine.

Cautions

When administering to young children and the elderly, special precautions must be taken. The plastic cuffs of endotracheal tubes can become damaged by topical preparations of lidocaine.

Patients who have impaired cardiac conduction, impaired cardiovascular disease, hypovolemia, shock, epilepsy, impaired respiratory function, or myasthenia gravis should use lidocaine hydrochloride injection with caution.

Additional Information