Lidocaine - instructions for use, dose, side effects, contraindications

Reducing the permeability of cell membranes of neurons for Na + ions, probably by attachment to sodium channels, and an increase in permeability for K +, which reversibly stabilizes the cell membrane and depresses its depolarization, disrupts the propagation of the action potential and leads to blockade of conductivity. For blockade of large nerve trunks, a higher concentration of the drug is required than for small peripheral nerves.

Pharmacokinetics:

Rapidly absorbed from the mucous membranes, especially from the mucous membrane of the airways; is fully subjected to systemic absorption, the speed of which depends on the site and route of administration, on the degree of blood supply to the injection site and blood flow velocity therein, on the administered dose (volume and concentration), duration of application in topical application, and combination with vasoconstrictors; after application to the mucous membrane of the upper respiratory tract is partially swallowed and inactivated in the digestive tract.Distributed quickly, first enters the well-blood-supplying tissues (heart, lungs, brain, liver, spleen), then into adipose and muscle tissue; penetrates the blood-brain barrier, the placental barrier and into breast milk (40% concentration in the mother plasma). The connection with plasma proteins is moderate or high (60-80% depending on the concentration). Biotransformation in the liver - 90-95%, involving microsomal enzymes by dealkylation of the amino group and breaking of the amide bond with the formation of active metabolites (monoethylglycinexylidine and glycinexylidin), and also in smaller quantities, active and toxic metabolites (the half-life of metabolites is 2 and 10 hours respectively); with liver diseases, the intensity of metabolism is reduced to 10-50% of the normal value. The half-life period is dose-dependent and is 1.5-2 hours in adults after an intravenous bolus injection (on average 100 minutes), in newborns - 3.2 hours; with the infusion of lidocaine within 24-48 hours, the half-life increases to 3 hours; if the liver functions are disturbed, the half-life can be increased 2 times. TCmax - usually 10-30 minutes when applied to the mucosa of the oral cavity and upper respiratory tract; 1-3 minutes after intravascular or trans-tracheal administration.TCss (after a long intravenous infusion) - 3-4 hours (8-10 hours for acute myocardial infarction). The therapeutic concentration in the plasma is 1.5-5 μg / ml (concentrations above 5 μg / ml are considered toxic). Elimination - kidney 10% in unchanged form, but mainly in the form of metabolites; Renal excretion may be preceded by excretion of bile with subsequent reabsorption from the digestive tract. With chronic renal failure, cumulation of metabolites is possible; Acidification increases the excretion of lidocaine. Relative toxicity compared with procaine - 2.

Indications:

Epidural anesthesia, caudal and lumbar, including in combination with epinephrine.

ICD-10

XX.Y40-Y59.Y48.4 Painkillers, unspecified

XXI.Z40-Z54.Z48.8 Other specified types of subsequent surgical care

Contraindications:

Hypersensitivity, including to other amide local anesthetics.

With subarachnoidal anesthesia: complete atrioventricular block, profuse bleeding, severe hypotension and shock (possibly aggravated by cardiodegression and vasodilation, while the metabolism of amides is also slowed),local infections in the area of presumed puncture (possible spread of infection in the subarachnoid space, changes in local pH reduce the effectiveness of anesthesia), sepsis (high risk of CNS stimulation).

For use as an antiarrhythmic drug: hypersensitivity, Morgagni-Adams-Stokes syndrome, atrioventricular, intraventricular and sinoatrial blockades (possibly exacerbated), syndrome Wolff-Parkinson-White, cardiogenic shock.

Carefully:No data.

Pregnancy and lactation:

Penetrates through the placenta by diffusion. Controlled studies in humans have not been conducted. In retrospective studies on the use of local anesthetics in emergency surgical interventions in pregnant women, a negative effect on the fetus was not revealed. In rats and rabbits, in doses up to 6.6 times the maximum recommended for humans, there is no adverse effect on the fetus, but with intravenous administration lidocaine can reduce uterine arteries of sheep in the experiment and significantly increase blood pressure and reduce or increase the heart rate of the fetus, depending on the speed of infusion.Excreted by breast milk, but the negative impact on the child is not described.

FDA recommendation category B, regardless of the route of administration.

Dosing and Administration:

Anesthesia for surgical interventions: 225-300 mg (15-20 ml) of 1.5% solution.

Anesthesia in obstetrics: 100-300 mg of a 0.5-1% solution.

Lumbar epidural anesthesia: 250-300 mg (25-30 ml) of 1% solution of 225-300 mg (15-20 ml) or a 1.5% solution of 200-300 mg (10-15 ml) of 2% solution.

Epidural thoracic anesthesia: 200-300 mg (20-30 ml) of 1% solution.

Side effects:

Systemic adverse reactions develop immediately or within 30 minutes after administration.

Hematological: anemia (Skin pallor, dyspnea on exertion, weakness, fatigue) methemoglobinemia (cyanosis lip and nail beds, shortness of breath, dizziness, weakness, headache, tachycardia).

The cardiovascular system: bradycardia (dizziness, possible heart failure), arrhythmia, chest pain (a consequence of the sympathomimetic effect of adding vasoconstrictors result of low perfusion with blood pressure lowering), hypertension (a consequence of the sympathomimetic effect of adding vasoconstrictors), hypotension, dizziness, tachycardia (triggered by adding vasoconstrictor), peripheral vasodilation.

GIT: constipation, fecal incontinence (one of the manifestations of the "ponytail" syndrome), nausea and / or vomiting.

Respiratory system: self-breathing (rarely).

Overdose:

Clinical manifestations when used as a local anesthetic: apnea, collapse (lowering blood pressure, rare or arrhythmic pulse, pallor, sweating, cardiac arrest possible), methaemoglobinaemia (dyspnea with exertion, dizziness, headache, weakness or fatigue), central neurotoxicity double vision, confusion, convulsions, dizziness, ringing or buzzing in the ears, trembling, irritability, excitement, nervousness, stimulation and then depression of the central nervous system, as well as loss of consciousness respiratory arrest).

Clinical manifestations when used as antiarrhythmics. When the concentration of lidocaine in the blood plasma is 6-8 mcg / ml: blurred vision or double vision, nausea or vomiting, ringing in the ears, tremor or muscle twitching, dizziness, euphoria, lowering blood pressure; when the concentration of lidocaine in the blood plasma is more than 8 μg / ml: difficulty breathing, severe dizziness or fainting, convulsions, bradycardia.

Treatment: in case of severe reactions, stop the drug administration, provide monitoring of the main indicators, airway patency and oxygen supply; at a collapse - infusion therapy and application of vasopressors. In case of hypotension, the woman in labor should be placed on her left side in order to eliminate the pressure of the pregnant uterus on the aorta and inferior vena cava; Delivery can improve the response to ongoing activities. With convulsions ensure patient safety and oxygen supply; in the absence of the effect of respiratory support - intravenous administration of benzodiazepines (diazepam with an increment of 2.5 mg) or barbiturates of ultrashort action (thiopental sodium, thiamylal with an increment of 50-100 mg; with intravenous administration of barbiturates, inhibition of hemocirculation is possible) with an interval of 2-3 minutes; with nekupiruemyh convulsions and the presence of artificial ventilation of the lungs are shown muscle relaxants; for a short time after the onset of seizures, rapid development of hypoxia, hypercapnia, and acidosis is possible; monitoring of blood pressure, heart rate, neurological status and respiratory function continuously.Supportive therapy: maintenance and maintenance of airway patency, if necessary - endotracheal intubation, artificial ventilation. With methemoglobinemia: in the absence of response to oxygen it is recommended to inject methylene blue (intravenously, for 1-2 minutes / 1-2 mg / kg as a 1% solution).

Interaction:

β-Adrenoblockers, including topical preparations in the presence of systemic absorption - may slow the metabolism and increase the risk of lidocaine toxicity due to decreased hepatic blood flow. Possible increased risk of bradycardia, including when used as antiarrhythmics and topical application in large quantities.

Aymalin, amiodarone, verapamil, phenytoin, quinidine - when combined with lidocaine, an increase in the negative inotropic effect is possible.

With the combined use of antiarrhythmics and other derivatives of local anesthetics-amides (mexiletine, tokainide) with lidocaine in high doses (as antiarrhythmics and with topical application) the higher the risk of cardiotoxicity due to the summation of effects and a more likely overdose.

In patients receiving anticoagulants (warfarin, heparin sodium, dalteparin sodium, danaparoid, adenoparin calcium, sodium enoxaparin), the trauma of blood vessels during epidural or subarachnoid administration of local anesthetics can lead to hemorrhage in the central nervous system or soft tissues.

Antimiasthenic drugs - local anesthetics, especially with rapid absorption in large quantities, inhibit the transmission of the nerve impulse, acting as antagonists of the action of antimiasthenic drugs on skeletal muscles. An adequate control of myasthenia gravis may require a temporary correction of the dose of antimiasthenic drugs.

Neuromuscular blockers - local anesthetics, especially with rapid absorption in large quantities, inhibit the transmission of a nerve impulse, which lengthens the action of neuro-muscular blockers.

Vasoconstrictors (methoxamine, phenylephrine, epinephrine) - it is not recommended to combine methoxamine and local anesthetics, since the effect of both drugs is prolonged, and prolonged exposure to methoxamine is accompanied by inhibition of circulation and skin debridement.When combining lidocaine with other vasoconstrictors, it is necessary to carefully observe the proportions, especially when anesthetizing areas of peripheral arteries (fingers, nose, penis), where blood supply to the gangrene is more likely.

Special instructions:

Local anesthetics are commonly used for local or regional anesthesia, analgesia, and motor blockage of varying degrees before surgery, dental procedures, or in the management of anesthesia, and are also used for other diagnostic and therapeutic purposes, provided that the dosages and routes of administration are met.

The effectiveness and safety of local anesthetics depends on the accuracy of their dosage and compliance with the technique of administration. Local anesthetics should be introduced by specialists with experience in the diagnosis and treatment of adverse reactions, cardiac rhythm and conduction disorders and other acute conditions. It is necessary to have equipment and medicines to stop severe toxic reactions.

Techniques for the introduction of local anesthetics are described in the literature.

Doses of local anesthetics depend on the type of anesthesia, the degree of vascularization of tissues in the injection zone,blocking nerve or plexus, type of surgical intervention (the number of blocked neuronal segments, the depth of anesthesia, the degree of muscle relaxation, the necessary duration of anesthesia), the age and body weight of the patient.

When describing the techniques of administration, average doses are usually given; the true dose is calculated individually, taking into account the age, anthropometric parameters and physical condition of the patient, as well as the expected rate of systemic absorption at the injection site and corrected depending on the response (when used as antiarrhythmics). Use the minimum dose (volume and concentration) sufficient to achieve the desired result.

Mixing or combining local anesthetics is used to accelerate the onset and lengthening of the action, while taking into account the summation of total toxicity.

Instructions

Lidocaine (Lidocainum)