Lidocaine

Lidocaine
Drug form and composition
Solution for injection. One ampoule of 2 ml (2%) contains 40 mg (20 mg/ml) Lidocaine hydrochloride. One ampoule of 10 ml (0.5%, 1% or 2%) contains 50 mg (5 mg/ml), 100 mg (10 mg/ml), 200 mg (20 mg/ml) Lidocaine hydrochloride respectively.
Indications
Lidocaine hydrochloride is used in different types local anesthesia in surgery, stomatology, urology, cardiology, ophthalmology, otorhinolaryngology, as well as in different invasive diagnostic manipulations. Preventively Lidocain is used in conditions predisposing to cardiac rhythm disorders; in patients with ventricular arrhythmias, particularly those accompanying a myocardial infarction, digitalis intoxication, and cardiac surgery.
Dosage and administration
In patients with cardiac rhythm disorders Lidocain is applied jet intravenously in initial loading dose 1-1.5 mg per kg body weight (mean dose 75-100 mg in adults) injected within 2 minutes. The same dose could be repeated in 10-minutes interval or 50 mg are injected jet intravenously within a minute. The latter dose is repeated 4 times in 5-10-minutes intervals. In order to maintain a therapeutic plasma concentration, the preparation is applied as a continuous infusion with rate 1-4 mg per kg body weight - up to total 24 hours dose 1.5-3 g within 2-3 days. In infiltration anesthesia total solution volume should not exceed 50-100 ml, 0.5% solution, depending on the type of surgery; in conduction and epidural anesthesia - 20-30 ml. Maximal volume should not exceed 500 ml, 0.5% solution or 250 ml, 1% solution.
Contraindications
Hypersensitivity to Lidocain; Adams-Stock’s syndrome; high degree AV - or SA - block.
Special warnings and precautions
Lidocain should not be used in severe heart failure; hepatal function disorders and severe liver diseases, particularly in cases with disturbed liver blood circulation; severe renal diseases and renal function disorders; shock and hypovolemia; incomplete heart block or sinus node bradycardia; WPW-syndrome; in newborns, as a danger of life-threatening side effects exists, including protracted convulsion. Cross-sensitivity reactions with other amide anesthetics were described. Lidocain should not be used in pregnant women, as it and its metabolites pass the placenta, which may lead to newborn's central nervous system depression, bradycardia etc. As the preparation may lead to blood pressure reduction and somnolence, it should be avoided in drivers and machinery-operating persons until the preparation effect disappears.
Drug interactions
In concomitant application of other antiarrhythmic medicines the Lidocain effect is enhanced. In concomitant application of anticonvulsuve preparations and hydantoin a depression of cardiac function is possibly to appear. In combined treatment with β-adrenoreceptor blockers (propranolol, atenolol, etc.) Lidocain plasma concentration is increased and a risk of intoxication exists. In high dosage and particularly in intravenous application of Lidocain together with neuro-muscular blockers the effect of both medicines is potentiated. Adrenalin, applied together with Lidocain, leads to prolongation of the local anesthesia. Adverse reactions
In patients with ventricular dysfunction rarely conduction disorders were seen. Administration of high dose Lidocain leads to the blood pressure decrease, rhythm disorders, heart block or heart arrest, and respiratory insufficiency. In therapeutic plasma concentrations or plasma levels slightly exceeding the therapeutic (1.5 - 6 mg/ml) insomnia, anxiety, dizziness, somnolence, emotional disorders, and visual disorders may appear.
Pharmacological mechanisms
Lidocain is a local anesthetic, belonging to the group of amides, possessing fast analgesic and antiarrhythmic effects. The effects of the preparation are due to a decrease of sensitivity of the pain receptors, retardation of the peripheral nerve conduction, and a prominent membrane-stabilization effect. In the place of application Lidocain inhibits the calcium ion influx, as well as (in lower degree) potassium ion reflux trough the neuron membrane, inhibiting depolarization and permeability of the latter. In the cardiac muscle the preparation exerts a selective antiarrhythmic activity, particularly in ventricular arrhythmias. It slightly depresses myocardial contractility, which make possibly to use the preparation in patients with heart failure. As Lidocain is fast metabolized by the liver microsomes its effect is of short duration. For this reason an intravenous application is recommended.
Supplied
50 ampoules of 10ml (0.5%, 1%, and 2%). 10 or 100 ampoules of 2 ml (40 mg).
Expiry
5 years