Lidocaine Bufus

General characteristics. Structure:

Active ingredient: 20 mg or 100 mg of lidocaine of a hydrochloride (in terms of anhydrous substance).

Excipients: sodium of chloride, hydroxide sodium (0,1 M solution of natron caustic), waters for injections.

Pharmacological properties:

Pharmacodynamics. Lidocaine on chemical structure belongs to acetanilide derivatives. Possesses the expressed mestnoanesteziruyushchy action and antiarrhytmic (Ib a class) action. Mestnoanesteziruyushchy action is caused by oppression of nerve conduction due to blockade of natrium channels in nerve terminations and nerve fibrils. Lidocaine considerably (by 2-6 times) surpasses Procainum in the anesthetic effect; effect of lidocaine develops quicker and longer – up to 75 min., and at simultaneous use with Epinephrinum – more than 2 hours. At topical administration expands vessels, has no local irritative effect.

Antiarrhytmic properties of lidocaine are caused by its ability to stabilize a cellular membrane, to block natrium channels, to increase permeability of membranes for potassium ions. Practically without influencing an electrophysiologic condition of auricles, lidocaine accelerates repolarization in ventricles, oppresses the IV phase of depolarization in Purkinye's fibers (a phase of diastolic depolarization), reducing their automatism and duration of action potential, increases the minimum potential difference at which myofibrils react to premature stimulation.

(Phase 0) does not influence the speed of bystry depolarization or slightly reduces. Has no significant effect on conductivity and contractility of a myocardium (conductivity only in big, close to toxic doses oppresses). Intervals of PQ, QRS and QT under its influence on an ECG do not change. The negative inotropic effect is also expressed slightly and is shown quickly only at bystry administration of drug in high doses.

Pharmacokinetics. Time of achievement of the maximum concentration in a blood plasma after intramuscular introduction – 5-15 minutes, at slow intravenous infusion without the initial sating dose – in 5-6 hours (patients with an acute myocardial infarction have 10 h). Communication with proteins of plasma – 50-80%. It is quickly distributed (distribution phase T1/2 – 6-9 minutes) in bodies and fabrics with good perfusion, including in heart, lungs, a liver, kidneys, then in muscular and fatty tissue.

Gets through a blood-brain and placental barrier, cosecretes with maternal milk (40% of concentration in mother's plasma). It is metabolized mainly in a liver (for 90-95% of a dose) with the participation of microsomal enzymes with formation of active metabolites – a monoetilglitsinksilidida and the glitsinksilidida having an elimination half-life of 2 h and 10 h respectively. Intensity of metabolism decreases at liver diseases (can make from 50 to 10% of a normal amount); at disturbance of perfusion of a liver at patients after a myocardial infarction and/or with congestive heart failure.

Elimination half-life at continuous infusion within 24-48 hours – about Z h; at a renal failure – can increase in 2 and more times. It is removed with bile and urine (to 10% of a dose in not changed look). Acidulation of urine promotes increase in removal of lidocaine.

Indications to use:

- Infiltration, conduction, spinal and epidural anesthesia.
- Terminal anesthesia in ophthalmology.
- Prevention of repeated fibrillation of ventricles at an acute coronary syndrome and repeated paroxysms of ventricular tachycardia (usually within 12-24 hour).
- The ventricular arrhythmias caused by glikozidny intoxication.

Route of administration and doses:

- For an infiltration anesthesia: vnutrikozhno, subcutaneously, intramusculary apply solution of lidocaine of 5 mg/ml (the maximum dose of 400 mg).
- For blockade of peripheral nerves and neuroplexes: perinevralno, 10-20 ml of solution of 10 mg/ml or 5-10 ml of solution of 20 mg/ml (no more than 400 mg).
- For conduction anesthesia: perinevralno apply solutions of 10 mg/ml and 20 mg/ml (no more than 400 mg).
- For epidural anesthesia: epiduralno, solutions of 10 mg/ml or 20 mg/ml (no more than 300 mg).
- For spinal anesthesia: subarakhnoidalno, Z-4 of ml of solution of 20 mg/ml (60-80 mg).
- In ophthalmology: solution of 20 mg/ml is dug in in a conjunctival sac on 2 drops by 2-Z times with an interval of 30-60 seconds just before surgical intervention or a research.

For lengthening of effect of lidocaine addition of ex tempore of 0,1% of solution of Epinephrinum (adrenaline) is possible (on 1 drop on 5-10 ml of solution of lidocaine, but no more than 5 drops on all volume of solution).

The lidocaine dose decline at elderly patients and patients with liver diseases (cirrhosis, hepatitis) or with a reduced hepatic blood-groove (chronic heart failure) for 25-50% is recommended.

As antiarrhytmic means: intravenously. Solution of lidocaine of 20 mg/ml is used for introduction of a load dose. Introduction begins with a load dose 1 mg/kg (within 2-4 minutes with a speed of 25-50 mg/min.) with immediate connection of continuous infusion with a speed of 1-4 mg/min. Owing to bystry distribution (an elimination half-life about 8 min.), in 10-20 min. after introduction of the first dose there is a decrease in concentration of drug in a blood plasma that can demand repeated bolyusny introduction (against the background of continuous infusion) in a dose equal 1/2-1/3 load doses, with an interval of 8-10 min. The maximum dose at 1 o'clock – 300 mg, in days – 2000 mg.

Intravenous infusion is carried usually out within 12-24 hours with continuous ECG monitoring then infusion is stopped to estimate need of change of antiarrhytmic therapy at the patient. Speed of removal of drug is reduced at heart failure and an abnormal liver function (cirrhosis, hepatitis) and at elderly patients that demands a dose decline and rate of administering of drug for 25-50%. At a chronic renal failure of dose adjustment it is not required.

Features of use:

It is necessary to cancel monoaminooxidase inhibitors not less than in 10 days, in case of the planned lidocaine use.

It is necessary to show care when carrying out local anesthesia of fabrics with high vascularization, in order to avoid an intravascular injection it is recommended to carry out aspiration test.

During treatment it is necessary to be careful during the driving of motor transport and occupation other potentially dangerous types of activity demanding the increased concentration of attention and speed of psychomotor reactions

Side effects:

From a nervous system, sense bodys and mentality: euphoria, headache, dizziness, drowsiness, general weakness, neurotic reactions, confusion or loss of consciousness, disorientation, spasms, sonitus, paresthesias, diplopia, nystagmus, photophobia, tremor, lockjaw of mimic muscles, alarm.

From cardiovascular system: a lowering of arterial pressure, bradycardia, a peripheral vazodilatation, a collapse, a stethalgia, a cardiac standstill, tachycardia – at introduction with a vasoconstrictor, arrhythmia.

Allergic reactions: skin rash, small tortoiseshell, itch, Quincke's disease, acute anaphylaxis.

From the alimentary system: nausea, vomiting.

Others: feeling of "heat" or "cold", resistant anesthesia, erectile dysfunction, a hypothermia, a methemoglobinemia, flashing of "front sights" before eyes.

Interaction with other medicines:

Beta adrenoblockers and Cimetidinum increase risk of development of toxic effects. Strengthens a muscular relaxation of kurarepodobny drugs. Joint appointment with beta adrenoblockers increases risk of development of bradycardia. Ajmalinum, Amiodaronum, verapamil and quinidine strengthen a negative inotropic effect.

Inductors of microsomal enzymes of a liver (barbiturates, Phenytoinum, rifampicin) reduce efficiency of lidocaine.

Vasoconstrictors (Epinephrinum, метоксамин, Phenylephrinum) extend mestnoanesteziruyushchy effect of lidocaine and can cause increase in arterial pressure and tachycardia.

Lidocaine reduces effect of anti-myasthenic means.

Combined use with procaineamide can cause excitement of the central nervous system, a hallucination.

Guanadrel, гуанетидин, мекамиламин, a trimetafana камзилат increase risk of the expressed lowering of arterial pressure and bradycardia.

Strengthens and extends action of muscle relaxants.

The combined use of lidocaine and Phenytoinum should be used with care as reduction of resorptive effect of lidocaine, and also development of undesirable cardiodepressive effect is possible.

Under the influence of inhibitors of a monoaminooxidase strengthening of mestnoanesteziruyushchy effect of lidocaine and a lowering of arterial pressure is probable. The patients accepting monoaminooxidase inhibitors should not appoint lidocaine parenterally.

At co-administration of lidocaine and polymyxin B it is necessary to monitor function of breath of the patient.

At the combined use of lidocaine with hypnotic drugs or sedatives, narcotic analgetics, hexenal or thiopental sodium strengthening of the oppressing action on the central nervous system and breath is possible.

At intravenous administration of lidocaine by the patient accepting Cimetidinum such undesirable effects as a condition of an oglushennost, drowsiness, bradycardia, paresthesias are possible. It is connected with increase in level of lidocaine in a blood plasma that is explained by release of lidocaine from communication with blood proteins, and also delay of its inactivation in a liver. In case of need carrying out a combination therapy these drugs it is necessary to reduce a lidocaine dose.

When processing the place of an injection the disinfecting solutions containing heavy metals the risk of development of local reaction in the form of morbidity and hypostasis increases.

Contraindications:

- sick sinus syndrome; the expressed bradycardia; an atrioventricular block of II and III degrees (except for cases when the probe for stimulation of ventricles is entered); sinuatrial blockade, WPW syndrome, acute and chronic heart failure (III-IV F. K.); cardiogenic shock; Adams-Stokes's syndrome; disturbance of intra ventricular conductivity;
- hypersensitivity to any of drug components;
- retrobulbar introduction by the patient with glaucoma;
- pregnancy, breastfeeding (gets through a placental barrier, it is allocated with breast milk).

With care – chronic heart failure of the II-III degree, arterial hypotension, a hypovolemia, an atrioventricular block of the I degree, a sinus bradycardia, a heavy liver and/or renal failure, a heavy myasthenia, epileptiform spasms (including in the anamnesis), a reduced hepatic blood stream, the weakened or elderly patients (65 years are more senior), children up to 18 years (owing to the slowed-down metabolism drug accumulation is possible), hypersensitivity to other amide mestnoanesteziruyushchy means in the anamnesis.

It is also necessary to consider the general contraindications to carrying out this or that type of anesthesia.

Overdose:

Symptoms: the first signs intoxicationsof - dizziness, nausea, vomiting, euphoria; lowering of arterial pressure, adynamy; then – spasms of mimic muscles with transition to toniko-clonic spasms of skeletal muscles, psychomotor excitement, bradycardia, an asystolia, a collapse; when using at childbirth, the newborn has a bradycardia, oppression of a respiratory center, an apnoea.

Treatment: termination of administration of drug, inhalation by oxygen. Symptomatic therapy. At spasms intravenously enter 10 mg of diazepam. At bradycardia – m-holinoblokatory (atropine), vasoconstrictors (Norepinephrinum, Phenylephrinum). Dialysis is inefficient.

Storage conditions:

List B. In the place protected from light at a temperature not above 25 °C. To store in the place, unavailable to children. A period of validity - 2 years. Not to use after the period of validity specified on packaging.

Issue conditions:

According to the recipe

Packaging:

Solution for injections of 20 mg/ml and 100 mg/ml. On 2 ml in ampoules of neutral glass or in ampoules polymeric of polyethylene of high pressure, or from polyethylene of low pressure, or from polyethylene for the medical purposes, or from polyethylene or polypropylene for infusion solutions and injection drugs. On 10 ampoules of neutral glass with the application instruction place in a box from a cardboard with a corrugated insert. Put a knife in each box ampoule or the scarificator.

When packaging ampoules with notches rings and points ampoule or scarificators do not put knives. On 10 ampoules polymeric with the application instruction place in a pack from a cardboard.