Lidocaine hydrochloride

Pharmacological properties

local anesthetic used for all types of local anesthesia: terminal, infiltration, conductor. the relative toxicity of lidocaine hydrochloride depends on the concentration of the solution. in a low concentration (0.5%), the drug does not significantly differ in toxicity from procaine, with an increase in concentration (1 and 2%), toxicity increases (by 40-50%).

Pharmacokinetics When applied topically on the mucous membranes, lidocaine is absorbed to varying degrees, depending on the dose and place of application (C_max achieved in 10–20 minutes); absorption is affected by the rate of perfusion through the mucous membrane. With a / m introduction C_max reached in 5-15 minutes. Binding to plasma proteins - 60–80% (depending on the dose). It easily penetrates the histohematological barriers, including the BBB. First it enters the tissues with good blood supply (heart, lungs, brain, liver, spleen), then into the adipose and muscle tissues. Penetrates through the placenta, in the body of a newborn, 40–55% of the concentration of the drug in the mother is determined.

It is metabolized to 90% in the liver by oxidative N-dealkylation with the formation of active metabolites: monoethyl glycinexilidine and glycinexilidine, T_½ which is 2 and 10 hours, respectively. The effect of the first passage is characteristic.

With impaired liver function T_½ can increase more than 2 times. In unchanged form, 5–20% is excreted in the urine.

Indications

Local anesthesia (terminal, infiltrative, conductive) in surgery, ophthalmology, dentistry, otolaryngology; blockade of peripheral nerves and plexuses in various pain syndromes.

Application

Before applying lidocaine hydrochloride, it is imperative to conduct a skin test for increased individual sensitivity to the drug, as evidenced by edema and redness of the injection site.

For local anesthesia, they are injected (s / c, i / m) and locally on the mucous membranes. Intravascular administration of the drug should be avoided.

For conduction anesthesia (including anesthesia of the brachial and sacral plexuses), the usual dose for adults is 5–10 ml of solution (100–200 mg of lidocaine).

To anesthetize fingers, nose, ears, 2-3 ml of r-ra (40-60 mg of lidocaine hydrochloride) are administered. The maximum dose of lidocaine hydrochloride solution for adults when used for conduction anesthesia is 10 ml (200 mg of lidocaine hydrochloride).

For all types of injectable pain relief, a combination of lidocaine with epinephrine (1:50 000–1: 100 000) is possible, except when the systemic effect of epinephrine is undesirable - increased sensitivity to epinephrine, hypertension, diabetes mellitus, glaucoma, or short-term anesthetic effect. Epinephrine slows down the absorption of lidocaine and prolongs its effect.

For anesthesia in ophthalmology, 2 drops of the solution are instilled into the conjunctival sac 2-3 times with an interval of 30-60 s immediately before the study or surgical intervention.

For terminal anesthesia, the mucous membranes are lubricated with lidocaine solution in a volume of not more than 20 ml for adults at a dose of up to 2 mg / kg body weight, the duration of anesthesia is 15-30 minutes. The maximum dose of solution for adults makes 20 ml.

In children with all types of peripheral anesthesia, the total dose of lidocaine hydrochloride should not exceed 3 mg / kg body weight.

Contraindications

Individual hypersensitivity to the components of the drug, as well as to other amide local anesthetics; history of epileptiform seizures associated with the introduction of lidocaine hydrochloride, av blockade of the II and III degrees, sinus node weakness syndrome, wpw syndrome, Adams-Stokes syndrome, severe heart failure (II – III degrees), severe arterial hypotension, bradycardia, cardiogenic shock; complete transverse heart block; myasthenia gravis; hypovolemia; porphyria; severe renal and / or liver failure; retrobulbar administration to patients with glaucoma; During pregnancy and breastfeeding; children under 12 years old.

Side effects

From the central and peripheral nervous system: dizziness, headache, weakness, motor anxiety, euphoria, nystagmus, loss of consciousness, drowsiness, sleep disturbances, visual (diplopia, photophobia) and auditory disturbances, tremor, trismus, convulsions (the risk of their development increases with hypercapnia and acidosis), paresthesia, paralysis of the respiratory muscles, motor blockade, impaired sensitivity, respiratory paralysis (most often develops with subarachnoid anesthesia), numbness of the tongue and lips (when used in dentistry).

On the part of the cardiovascular system: when used in high doses - lowering blood pressure, bradycardia, when administered with a vasoconstrictor - tachycardia, slowing heart conduction, transverse heart block, collapse, hypertension, peripheral vasodilation, chest pain, arrhythmia, heart block, cardiac arrest.

From the respiratory system: respiratory depression, respiratory arrest, shortness of breath.

From the digestive tract: nausea, vomiting.

Allergic reactions: skin rashes, urticaria, pruritus, angioedema, generalized exfoliative dermatitis, anaphylactoid reactions, conjunctivitis, rhinitis.

Local reactions: a burning sensation that disappears with the development of an anesthetic effect.

Others: hypothermia, sensation of heat, cold, or numbness of limbs. When used in high doses - tinnitus, a state of excitement.

special instructions

Before applying lidocaine, a skin test is mandatory for an individual sensitivity to the drug, as evidenced by edema and redness of the injection site. when introduced into vascularized tissues, an aspiration test is recommended and administered carefully to prevent lidocaine from entering the bloodstream. before the introduction of lidocaine hydrochloride in high doses, the appointment of barbiturates is recommended.

When treating the injection site with disinfectant solutions containing heavy metals, the risk of developing a local reaction in the form of pain and swelling increases.

During the use of lidocaine, ECG monitoring is mandatory. In case of disturbance of the sinus node activity, change in the duration of the P – Q interval, expansion of the QRS, or with the development of arrhythmia, the dose should be reduced or the drug should be discontinued.

It is used with caution and at lower doses in patients with heart failure, AH, incomplete AV blockade, impaired intraventricular conduction, impaired liver and kidney function, epilepsy, after heart surgery, with a genetic tendency to hyperthermia, in debilitated patients. Caution should be used in elderly patients, as well as with a history of arrhythmias.

When conducting planned subarachnoid anesthesia, MAO inhibitors must be canceled at least 10 days before anesthesia.

During pregnancy and breastfeeding. The use of the drug during pregnancy is contraindicated. If it is necessary to use the drug, breast-feeding should be discontinued.

Children. Do not use in children under the age of 12 years.

The ability to influence the reaction rate when driving vehicles and working with other mechanisms. After the use of lidocaine hydrochloride is not recommended to engage in activities that require the speed of psychomotor reactions.

Interactions

Lidocaine enhances the inhibitory effect on the respiratory center of anesthesia drugs (hexobarbital, thiopental sodium iv), sleeping pills and sedatives.

With simultaneous use with hypnotics and sedatives, it is possible to increase the inhibitory effect on the central nervous system. Ethanol enhances the inhibitory effect of lidocaine on respiratory function.

With simultaneous use with β-adrenoreceptor blockers, a dose reduction of lidocaine is necessary.With simultaneous use with polymyxin B, monitoring of respiratory function is necessary. During treatment with MAO inhibitors, lidocaine should not be used parenterally, as this increases the risk of developing arterial hypotension. With simultaneous use with procainamide, hallucinations are possible. Lidocaine can enhance the effect of drugs that cause blockade of neuromuscular transmission, since the latter reduce the conductivity of nerve impulses. With cardiac glycoside intoxication, lidocaine may increase the severity of AV block. Lidocaine weakens the cardiotonic effect of cardiac glycosides.

Caution is prescribed simultaneously with:

• β-adrenoreceptor blockers - the metabolism of lidocaine in the liver slows down, the effects of lidocaine (including toxic) are enhanced and the risk of developing bradycardia and arterial hypotension is increased;
• curare-like drugs - it is possible to deepen muscle relaxation (up to paralysis of the respiratory muscles);
• norepinephrine, mexiletine - lidocaine toxicity increases (lidocaine clearance decreases);
• isadrine, glucagon - increased lidocaine clearance;
• midazolam - increases the concentration of lidocaine in blood plasma;
• anticonvulsants, barbiturates (including phenobarbital) - it is possible to accelerate the metabolism of lidocaine in the liver, a decrease in blood concentration;
• antiarrhythmic drugs (amiodarone, verapamil, quinidine, aymalin, disopyramide, propafenone), anticonvulsants (hydantoin derivatives) - cardiodepressive effect is enhanced; simultaneous use with amiodarone can lead to the development of seizures;
• procaine, procainamide - possibly an exciting effect on the central nervous system and the occurrence of hallucinations;
• morphine - the analgesic effect of morphine is enhanced;
• prenylamine - increases the risk of developing ventricular arrhythmias like pirouette;
• rifampicin - a decrease in the concentration of lidocaine in the blood is possible;
• phenytoin - enhances the cardiodepressive effect of lidocaine;
• vasoconstrictors (epinephrine, methoxamine, phenylephrine) - help slow down the absorption of lidocaine and prolong its action.

Incompatibility. The drug should not be mixed with other drugs in the same container. Lidocaine precipitates when mixed with amphotericin B, methohexital or sulfathiazole. Depending on the pH of the solution, lidocaine may not be compatible with ampicillin.

Overdose

The main symptoms are associated with inhibition of the function of the central nervous system and the cardiovascular system: general weakness, dizziness, disorientation, tonic-clonic convulsions, coma, tremor, visual impairment, av blockade, asphyxia, nausea, vomiting, euphoria, psychomotor agitation, asthenia, apnea , bradycardia, decreased hell, collapse. the first symptoms of an overdose in healthy people occur when the concentration of lidocaine hydrochloride in the blood is 0.006 mg / kg; convulsions - at 0.01 mg / kg.

Treatment: cessation of drug administration, oxygen therapy, vasoconstrictors (norepinephrine, phenylephrine), anticonvulsants, anticholinergics. The patient should be in a horizontal position; it is necessary to provide access to fresh air, oxygen supply and / or artificial respiration. Symptoms of the central nervous system are corrected by the use of benzodiazepines or short-acting barbiturates. If an overdose occurs during anesthesia, a short-acting muscle relaxant should be used. Atropine (0.5–1.0 mg IM) is used for the correction of bradycardia and conduction disturbance, with arterial hypotension sympathomimetics in combination with β-adrenergic agonists. When cardiac arrest is shown emergency resuscitation. Intubation, mechanical ventilation is possible. In the acute phase of an overdose of lidocaine, dialysis is ineffective. There is no specific antidote.

Storage conditions

In the dark place at a temperature of no higher than 25 ° C.

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