G-Lidocaine

Lidocaine Injection is indicated-

• As a local anaesthetic for use in infiltration blockade and intravenous regional analgesia.
• For the prevention and treatment of ventricular tachyarrhythmias

Lidocaine acts mainly by inhibiting sodium influx through sodium specific ion channels in the neuronal cell membrane, in particular the so called voltage-gated sodium channels. When the influx of sodium is interrupted, an action potential cannot arise and signal conduction is inhibited. The receptor site is thought to be located at the cytoplasmic (inner) portion of the sodium channel. Lidocaine binds more readily to sodium channels in activated state, thus onset of neuronal blockade is faster in neurons that are rapidly firing. This is referred to as state dependent blockade.

Cimetidine can impair the metabolism of lidocaine absorbed into the circulation. Elimination will be delayed and the risk of adverse reactions increased. Significant increases in plasma lidocaine concentrations have occurred during concomitant therapy with beta blockers such as propranolol, metoprolol or nadolol. It prolongs the duration of action of suxamethonium.

In common with other local anaesthetics, adverse reactions to lidocaine are rare and are usually the result of excessively high blood concentrations due to inadvertent intravascular injection, excessive dosage, rapid absorption or occasionally to hypersensitivity, idiosyncracy or diminished tolerance on the part of the patient. In such circumstances systemic effects occur involving the central nervous system and/or the cardiovascular system. CNS reactions are excitatory and/or depressant and may be characterized by nervousness, dizziness, blurred vision and tremors, followed by drowsiness, convulsions, unconsciousness and possibly respiratory arrest. Cardiovascular reactions are hypotension, myocardial depression, bradycardia and possibly cardiac arrest. Allergic reactions are extremely rare. They may be characterized by cutaneous lesions, urticaria, oedema or anaphylactoid reactions.

Although there is no evidence from animal studies of harm to the foetus, as with all drugs, it should not be given during early pregnancy unless the benefits are considered to outweigh the risks. Caution should be exercised when it is administered to a nursing woman.

Lidocaine for infiltration and nerve block should be employed only by clinicians who are well versed in diagnosis and management of dose-related toxicity. The safety and effectiveness of lidocaine depend on proper dosage, correct technique, adequate precautions, and readiness for emergencies. Standard text books should be consulted for specific techniques and precautions for various regional anaesthetic procedures. Resuscitative equipment, oxygen and other resuscitative drugs should be available for immediate use.

It should be used cautiously in patients with epilepsy, impaired cardiac conduction, bradycardia, impaired respiratory function and in patients with impaired hepatic function, if the dose or site of administration is likely to result in high blood levels. The effect of local anaesthetics may be reduced if an injection is made into an inflamed or infected area. Repeated doses of lidocaine may cause significant increases in blood levels with each repeated dose because of slow accumulation of the drug or its metabolites. Tolerance to elevated blood levels varies with the status of the patient. Careful and constant monitoring of cardiovascular and respiratory vital signs and the patient’s state of consciousness should be accomplished after each local anaesthetic injection.

Dosages in children should be reduced, commensurate with age, body-weight and physical condition. Elderly patients may be more sensitive to systemic effects and may require dose reductions.

Local & Surface anesthesia

Keep below 25°C temperature, away from light & moisture. Keep out of the reach of children.