Lidocaine hydrochloride

General characteristics. Structure:

Active ingredient: lidocaine a hydrochloride - 40 mg in 2 ml or 50 mg in 5 ml of solution; excipients: sodium hydroxide, sodium chloride, water for injections.

Description: transparent colourless or slightly yellowish color liquid.

Pharmacological properties:

Pharmacodynamics. Has mestnoanesteziruyushchy effect, stabilizing membranes of neurons, reducing their permeability for sodium ions that interferes with generation and carrying out nervous impulses. Suppresses carrying out not only painful impulses, but also impulses of other modality.

The anesthetic effect of lidocaine is 2 - 6 times stronger, than Procainum (works quicker and longer - up to 75 min., and after addition of Epinephrinum - more than 2 h). At topical administration expands vessels, has no local irritative effect on fabrics.

Has antiarrhytmic (Ib a class) properties. Shortens duration of action potential and the effective refractory period. Practically without influencing auricles, accelerates repolarization in ventricles. In therapeutic doses improves conductivity in Purkinye's fibers, preventing formation of a phenomenon of "a repeated entrance" (re-entry), especially in the conditions of ischemic injury of a muscle of heart, for example, at a myocardial infarction.

Practically does not influence conductivity and contractility of a myocardium (oppression of conductivity is noted at appointment only in big, close to toxic doses) - duration of intervals of PQ, QT and width of the QRS complex on the electrocardiogram does not change. The negative inotropic effect is expressed slightly and is shown quickly at bystry administration of drug in high doses.

Pharmacokinetics. At parenteral administration extent of absorption depends on an injection site and a dose. At intravenous jet administration the maximum concentration of lidocaine in a blood plasma is created in 3-5 min., at intramuscular – in 5-15 min. Communication with proteins of plasma – 50 - 80%. It is distributed quickly (distribution phase T1/2 – 6-9 min.). At first comes to well krovo-supplied fabrics (heart, lungs, a brain, a liver, a spleen), then to fatty and muscular fabrics. Gets through a blood-brain barrier, a placental barrier and into breast milk (40% of concentration in mother's plasma).

Is metabolized in a liver (for 90 - 95%) with participation of microsomal enzymes by deamination with formation of active metabolites (моноэтилглицинксилидин and глицинксилидин) which T1/2 makes 2 h and 10 h respectively. At liver diseases intensity of metabolism decreases and makes from 50% to 10% of a normal amount.

The elimination half-life after intravenous bolyusny administration - 1,5-2 h, at newborns is 3 h, at long intravenous infusions — to 3 h and more. At an abnormal liver function the elimination half-life can increase twice and more.

It is removed with bile and kidneys (to 10% in not changed look). At a chronic renal failure cumulation of metabolites is possible. Acidulation of urine promotes increase in removal of lidocaine.

Indications to use:

- infiltration, terminal, spinal and conduction anesthesia;

- treatment and prevention mono - and polytopic ventricular premature ventricular contraction and tachycardia of various genesis, especially in an acute phase of a myocardial infarction;

- stopping of fibrillation of ventricles;

- supportive application at cardiac defibrillation;

- as solvent (solution of lidocaine of 10 mg/ml) for preparation of solutions for intramuscular introduction - laktamny antibiotics of group of cephalosporins.

Route of administration and doses:

For carrying out anesthesia the amount of medicine and the general dose depends on a type of anesthesia and the nature of surgery.

At an infiltration anesthesia about 30 ml of solution with concentration of 10 mg/ml (1%) are used.

At conduction anesthesia apply solutions with concentration of 10 mg/ml (1%) and 20 mg/ml (2%); the maximum general dose - to 400 mg (40 ml of 1% of solution and 20 ml of 2% of solution of lidocaine). In dental practice use 1 - 5 ml (20 - 100 mg) of 2% of solution; at blockade of intercostal nerves – 3-5 ml (30-50 mg) of 1% of solution; at paracervical anesthesia - 10 ml (100 mg) of 1% of solution in each party (perhaps repeated introduction not less than in 1,5 h); at blockade according to Oberst-Lukashevich – 2 - 3 ml of 2% of solution.

Vagosympathetic blockade: cervical department - 5 ml (50 mg) of 1% of solution, lumbar – 5 - 10 ml (50 - 100 mg) of 1% of solution.

Epidural anesthesia - is used by 200 - 300 mg (10-15 ml) of 2% of solution of lidocaine. It is not recommended to use continuous administration of anesthetic by means of a catheter; introduction of the maximum dose should not repeat more often than in 90 min.

(At an intubation of a trachea, a bronkhoezofagoskopiya, a fibrogastroduodenoskopiya, removal of polyps, punctures of a Highmore's bosom, etc.) apply 2% to anesthesia of mucous membranes solution of no more than 20 ml.

In ophthalmology: 2 drops of 2% of solution dig in in a conjunctival sac 2 - 3 times with an interval of 30 - 60 seconds just before surgical intervention or a research.

The maximum dose for adults - no more than 4,5 mg/kg or 300 mg.

To children against the background of muscle relaxation introduction of 5 mg/kg of 1% of solution is possible.

For lengthening of effect of lidocaine addition of ex tempore of 0,1% of solution of adrenaline is possible (1 drop on 5 - 10 ml of solution of lidocaine, but no more than 5 drops). At the same time the most admissible dose of lidocaine increases to 500 mg.

As antiarrhytmic means: at ventricular arrhythmias, especially after a myocardial infarction: intravenously, patients without explicit disturbances have blood circulations of 100 mg in the form of a bolus within several minutes (not heavy patients have 50 mg or with heavy circulator disturbances), right after bolyusny introduction: infusions of 4 mg/min. within 30 min., 2 mg/min. within 2 hours, then 1 mg/min.; further to continue to reduce concentration if injection continuation more than 24 hours (monitoring of an ECG and consultation of specialists is necessary for continuation of infusions).

To children intravenously struyno 1 mg/kg (usually 50-100 mg) as a load dose at rate of administering of 25-50 mg/min. (i.e. within 3 - 4 min.); if necessary introduction of a dose is repeated in 5 min. then appoint continuous intravenous infusion. Intravenously, in the form of continuous infusion (usually after a load dose): the maximum dose for children - 30 mkg/kg/min. (20 - 50 mkg/kg/min.).

Note: after intravenous administration lidocaine has the short duration of action (lasting 15-20 min.). If intravenous injection by drop infusion is not available, after immediate initial intravenous administration it is possible to repeat 50-100 mg if necessary one or two times with an interval not less than 10 min.

For preparation of infusion solution of 1 g or 2 g of lidocaine add to 1 l 5% of solution of a dextrose for injections and receive lidocaine solution in concentration of 1 mg/ml or 2 mg/ml.

At elderly patients reduction of a dose is recommended, especially at long intravenous infusion. At a chronic renal failure of dose adjustment it is not required. At liver diseases (cirrhosis, hepatitis) and at patients with a reduced hepatic blood-groove (for example, against the background of chronic heart failure) the dose has to be lowered by 40-50%.

Attention!

At bystry intravenous administration there can be a sharp lowering of arterial pressure and develop a collapse. In these cases apply Phenylephrinum, ephedrine and other vasoconstrictors.

1% apply solution of lidocaine as solvent to preparation of injection solutions for intramuscular introduction of m-laktamnykh of antibiotics of group of cephalosporins at the rate of 3 ml of lidocaine on the bottle containing 1,0 g of an antibiotic.

Features of use:

Pregnancy and lactation. Pregnant women and the feeding women should appoint medicine according to strict indications, having weighed the expected advantage of therapy for mother and potential risk for a fruit.

Use in pediatrics. At children dose adjustment according to age and the physical status is necessary.

Extra care. Preventive appointment as everything without exception is not recommended to patients with an acute myocardial infarction (routine preventive purpose of lidocaine can increase risk of death due to increase in frequency of emergence of asystolias).

At inefficiency of lidocaine it is necessary to exclude first of all a hypopotassemia, in urgent situations there are several options of further actions: careful increase in a dose up to emergence of side effects from the central nervous system (block, the complicated speech); appointment, sometimes joint, class drugs IA (procaineamide), transition to class drugs III (Amiodaronum, bretylium tosylate).

It is forbidden to enter lidocaine solutions retrobulbarno the patient with glaucoma.

It is necessary to enter carefully lidocaine into strongly vaskulyarizovanny fabrics in order to avoid intravazalny hit of drug. At introduction to vaskulya-rizirovanny fabrics it is recommended to carry out aspiration test.

Influence on ability to driving of motor transport and control of mechanisms. 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 and sense bodys: euphoria, dizziness, flashing of "front sights" before eyes, a photophobia, neurotic reactions, a headache, uneasiness, a sonitus, a diplopia, spasms, a tremor, drowsiness, paresthesias, a disorientation, confusion of consciousness.

From cardiovascular system: a lowering of arterial pressure, a collapse, bradycardia (up to a cardiac standstill).

From the alimentary system: numbness of language and mucous membrane of an oral cavity, nausea, vomiting.

Allergic reactions: urticaria, itch, acute anaphylaxis.

Others: heat, cryesthesia.

Interaction with other medicines:

Joint appointment with beta adrenoblockers increases risk of development of bradycardia and toxic effects of lidocaine.

Cimetidinum and propranolol reduce hepatic clearance of lidocaine (decrease in metabolism owing to inhibition of a microsomal oxidation and decrease in a hepatic blood-groove) and increase risk of development of toxic effects.

Barbiturates, Phenytoinum, rifampicin (inductors of microsomal enzymes of a liver) reduce efficiency (increase in a dose can be required).

At appointment with Ajmalinum, Phenytoinum, verapamil, quinidine, Amiodaronum strengthening of a negative inotropic effect is possible.

Cardiac glycosides weaken cardiotonic effect, kurarepodobny medicines strengthen a muscular relaxation.

Procaineamide increases risk of development of excitement of the central nervous system, hallucinations.

At co-administration of lidocaine, barbiturates, other hypnotic drugs and sedative medicines strengthening of their oppressing action on the central nervous system is possible.

Under the influence of monoamine oxidase inhibitors strengthening of mestnoanesteziruyushchy effect of lidocaine is possible. The patients accepting monoamine oxidase inhibitors should not appoint lidocaine parenterally.

At simultaneous use of lidocaine and polymyxin B strengthening of the oppressing influence on neuromuscular transmission is possible (monitoring of respiratory functions is necessary).

Contraindications:

• hypersensitivity;

• a sick sinus syndrome (especially at patients of advanced age);

• WPW-syndrome;

• heart blocks: atrioventricular the III degrees (except for cases when the probe for stimulation of ventricles is entered), intra ventricular; sinus and atrial);

• disturbances of intra ventricular conductivity;

• cardiogenic shock;

• for anesthesia in obstetric practice – disturbances of pre-natal fetation, fetoplacental insufficiency, prematurity, postmaturity, a gestosis.

• for epidural anesthesia – heavy hypotension, cardiogenic shock and hypovolemic shock, neurologic diseases, a septicaemia, impossibility of carrying out a puncture because of deformation of a backbone;

• for subarachnoidal anesthesia – a dorsodynia, brain infections, high-quality and malignant new growths of a brain, a coagulopathy of various genesis, migraine, subarachnoidal hemorrhage, arterial hypertension and hypotension, paresthesias, psychosis, hysteria, not contact patients, impossibility of carrying out a puncture because of deformation of a backbone.

Cautions at use

With care apply at the chronic heart failure of the II-III degree, a heavy liver and/or renal failure, a hypovolemia, an atrioventricular block of the I-II degree, a sinus bradycardia, arterial hypotension, a heavy myasthenia, epileptiform spasms caused by lidocaine (including in the anamnesis), genetic predisposition to a malignant hyperthermia, pregnancy, in the period of a lactation, acute diseases, the weakened patient, at younger children's age, at advanced age.

Overdose:

Symptoms: initial signs intoxicationsof - dizziness, nausea, vomiting, euphoria, an adynamy, a lowering of arterial pressure; then - spasms of mimic muscles of the person, toniko-clonic spasms of skeletal muscles, psychomotor excitement, bradycardia, a collapse; when using in labor at the newborn - bradycardia, oppression of a respiratory center, an apnoea.

Treatment: at emergence of the first symptoms of intoxication introduction is stopped, the patient is transferred to horizontal position; appoint oxygen inhalations. At spasms - intravenously 10 mg of diazepam. At bradycardia - m-holinoblokatory (atropine), vasoconstrictors (Norepinephrinum, Phenylephrinum). Carrying out an intubation, artificial ventilation of the lungs, resuscitation actions is possible. Dialysis is inefficient.

Storage conditions:

In the place protected from light, at a temperature not over 25 ºС.

To store in the place, unavailable to children.

Period of validity 2 years. Not to use after expiry date.

Issue conditions:

According to the recipe

Packaging:

Solution for injections of 10 mg/ml: in ampoules on 5 ml, in packaging No. 5№2; No. 10.

Solution for injections of 20 mg/ml: in ampoules on 2 ml, in packaging No. 10:1; No. 10.