Lidocaine

The toxicity of lidocaine increases when it is used simultaneously with cimetidine and propranolol due to an increase in the concentration of lidocaine; this requires a reduction in the dose of lidocaine. Both drugs reduce hepatic blood flow. In addition, cimetidine inhibits the microsomal activity of liver enzymes.

Ranitidine, Diltiazem, verapamil, propranolol and other β-blockers reduce the clearance of lidocaine, which leads to an increase in its concentration in the blood plasma.

Antiviral agents (eg, amprenavir, atazanavir, darunavir, lopinavir) can also cause increased serum concentrations of lidocaine.

Hypokalemia caused by diuretics may reduce the effect of lidocaine when used simultaneously (see section "Special Instructions"). Lidocaine should be used with caution in patients receiving other local anesthetics or agents structurally similar to amide-type local anesthetics (eg, antiarrhythmic agents such as mexiletine, tocainide) because systemic toxic effects are additive.

When lidocaine is used in combination with narcotic analgesics, hexenal or sodium thiopental, the inhibitory effect on the central nervous system and respiration may be enhanced.

Separate drug interaction studies have not been conducted between lidocaine and class III antiarrhythmic drugs (eg, amiodarone), but caution is recommended when using them together.

In patients concomitantly receiving antipsychotics that prolong or have the potential to prolong the QT interval (e.g., pimozide, sertindole, olanzapine, quetiapine, zotepine), prenylamine, epinephrine (with occasional intravenous administration), or 5-HT3-serotonin receptor antagonists (e.g., tropisetron, dolasetron), the risk of developing ventricular arrhythmias may increase.

Concomitant use of quinupristin/dalfopristin may increase lidocaine concentrations and thus increase the risk of developing ventricular arrhythmias; their simultaneous use should be avoided.

Patients receiving muscle relaxants (eg, suxamethonium) may have an increased risk of enhanced and prolonged neuromuscular blockade.

Cardiovascular insufficiency has been reported following the use of bupivacaine in patients receiving verapamil and timolol; lidocaine is similar in structure to bupivacaine.

Dopamine and 5-hydroxytryptamine lower the seizure threshold in patients receiving lidocaine.

Opioids appear to have anticonvulsant effects, supported by evidence that lidocaine lowers the seizure threshold to fentanyl in humans.

Combinations of opioids and antiemetics, sometimes used for sedation in children, may lower the seizure threshold to lidocaine and increase its CNS depressant effects.

The use of epinephrine with lidocaine may reduce systemic absorption, but with accidental intravenous administration the risk of ventricular tachycardia and ventricular fibrillation increases sharply.

Concomitant use of other antiarrhythmic drugs, beta-blockers and slow calcium channel blockers may further reduce AV conduction, ventricular conduction and myocardial contractility.

The simultaneous use of vasoconstrictors increases the duration of action of lidocaine.

Concomitant use of lidocaine and ergot alkaloids (eg, ergotamine) can cause severe hypotension.

Caution must be exercised when using sedatives as they may interfere with the action of local anesthetics on the central nervous system. Caution should be exercised when using antiepileptic drugs (phenytoin), barbiturates and other inhibitors of liver microsomal enzymes, as this may lead to decreased effectiveness and, as a result, an increased need for lidocaine. On the other hand, intravenous administration of phenytoin may enhance the depressant effect of lidocaine on the heart.

The analgesic effect of local anesthetics can be enhanced by opioids and clonidine.

The combined use of lidocaine with procainamide can cause central nervous system stimulation and hallucinations.

When using lidocaine and polymyxin-B simultaneously, it is necessary to monitor the patient's respiratory function. Ethyl alcohol, especially with prolonged abuse, can reduce the effect of local anesthetics. Lidocaine is not compatible with amphotericin B, methohexitone, nitroglycerin.

With the simultaneous use of lidocaine with narcotic analgesics, an additive effect develops, which is used during epidural anesthesia, but increases the depression of the central nervous system and respiration.

Vasoconstrictors (epinephrine, methoxamine, phenylephrine) prolong the local anesthetic effect of lidocaine and can cause increased blood pressure and tachycardia.

Use with monoamine oxidase inhibitors (furazolidone, procarbazine, selegipine) probably enhances the local anesthetic effect of lidocaine and increases the risk of lowering blood pressure. Guanadrel, guanethidine, mecamylamine, grimstaphane camsylate increase the risk of a pronounced decrease in blood pressure and bradycardia. Anticoagulants (including ardeparin sodium, dalteparin sodium, danaparoid sodium, enoxaparin sodium, heparin, warfarin, etc.), nonsteroidal anti-inflammatory drugs (NSAIDs) or plasma expanders increase the risk of bleeding.

Lidocaine reduces the cardiotonic effect of digitoxin.

Lidocaine reduces the effect of antimyasthenic drugs (prozerin, oxazil, etc.), enhances and prolongs the effect of muscle relaxant drugs.

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.

Mixing lidocaine with other medications is not recommended.

When is lidocaine indicated?

The range of indications for Lidocaine solution includes the following conditions:

Local anesthesia required for manipulations in ophthalmology, ENT practice, dentistry, and surgery.
The use of cephalosporin group of antibacterial drugs as a solvent, the administration of which is characterized by a pronounced pain effect.

Lidocaine for injection allows you to anesthetize the desired area of skin or mucous membrane for several hours, which will be enough for medical manipulation accompanied by increased sensitivity.

Contraindications to the use of Lidocaine (spray, injection) during pregnancy

Before using any drug, the doctor should check with the woman for possible contraindications. For Lidocaine, this list is as follows:

Individual hypersensitivity reaction.
Low blood pressure.
Pathologies of the liver and/or kidneys.
Disturbances in the functioning of the cardiovascular system.

Lidocaine during pregnancy - reviews of the drug

Despite the restrictions on the use of Lidocaine during pregnancy, many doctors still use this drug for anesthesia during various medical procedures. The experience of most women who have already given birth is based on a single administration of the drug. No negative phenomena were noted, the children were born on time and without developmental deviations. A number of women noted that the drug was prescribed as part of an antibacterial “cocktail” in the second half of pregnancy. There were also no significant negative consequences noted.

To summarize, it is worth noting that despite the warnings of the drug manufacturers, the drug still finds use in such a category of patients as pregnant women. It is difficult to answer for sure whether Lidocaine is harmful during pregnancy. While there are potential risks from exposure of the drug to the baby in the womb, there is no statistical data regarding a higher number of complicated pregnancies after a single use of Lidocaine. The drug is a drug of last resort, so you should not use it unless absolutely necessary, especially since the modern pharmaceutical market can offer safer alternatives (for example, Ultracaine).

How does lidocaine affect pregnancy and the fetus?

Lidocaine cannot be considered an absolutely safe drug, but panic after a single use of the drug (not earlier than the second trimester) should not be caused either. The main concerns associated with the use of Lidocaine are based on its ability to easily penetrate the placental barrier, and therefore into the baby’s body.

The use of anesthesia in the first weeks of pregnancy can cause congenital deformities. The use of lidocaine even externally during early pregnancy is strictly not recommended.
At later stages, it is necessary to be extremely careful if there is a tendency to arterial hypotension. A dangerous decrease in a woman’s blood pressure can lead to oxygen starvation of the baby.
Exceeding the permissible dosage can lead to the development of bradycardia in a child.
Using the product after 28 weeks of gestation may cause premature birth. In the last months of pregnancy, a woman’s abdominal organs experience maximum pressure from the uterus, and blood flow may be disrupted. Pressure in the epigastric area often provokes tightness of the thoracic region, and the pregnant woman may experience shortness of breath. The use of Lidocaine can cause difficulty breathing, decreased blood pressure, and muscle spasms. The listed phenomena can seriously disrupt the course of pregnancy and lead to its completion ahead of schedule.

Description of the drug LIDOCAINE HYDROCHLORIDE

When used simultaneously with barbiturates (including phenobarbital), it is possible to increase the metabolism of lidocaine in the liver, reduce the concentration in the blood plasma and, as a result, reduce its therapeutic effectiveness.

When used simultaneously with beta-blockers (including propranolol, nadolol), the effects of lidocaine (including toxic ones) may be enhanced, apparently due to a slowdown in its metabolism in the liver.

When used simultaneously with MAO inhibitors, the local anesthetic effect of lidocaine may be enhanced.

When used simultaneously with drugs that block neuromuscular transmission (including suxamethonium chloride), the effect of drugs that block neuromuscular transmission may be enhanced.

When used simultaneously with hypnotics and sedatives, the inhibitory effect on the central nervous system may be enhanced; with ajmaline, quinidine - possible increased cardiodepressive effect; with amiodarone - cases of seizures and SSSS have been described.

When used simultaneously with hexenal, sodium thiopental (iv), respiratory depression is possible.

When used simultaneously with mexiletine, the toxicity of lidocaine increases; with midazolam - a moderate decrease in the concentration of lidocaine in the blood plasma; with morphine - enhances the analgesic effect of morphine.

When used simultaneously with prenylamine, there is a risk of developing ventricular arrhythmias.

Cases of agitation and hallucinations have been described when used simultaneously with procainamide.

When used simultaneously with propafenone, the duration and severity of side effects from the central nervous system may increase.

It is believed that under the influence of rifampicin, a decrease in the concentration of lidocaine in the blood plasma is possible.

With simultaneous intravenous infusion of lidocaine and phenytoin, side effects of central origin may increase; a case of sinoatrial block due to the additive cardiodepressive effect of lidocaine and phenytoin is described.

In patients receiving phenytoin as an anticonvulsant, a decrease in the concentration of lidocaine in the blood plasma is possible, which is due to the induction of microsomal liver enzymes under the influence of phenytoin.

When used simultaneously with cimetidine, the clearance of lidocaine moderately decreases and its concentration in the blood plasma increases, and there is a risk of increased side effects of lidocaine.

How is lidocaine solution used?

The local anesthetic solution is pre-tested on a separate area of the skin, which makes it possible to assess the presence or absence of an individual negative reaction to the drug.

The dosage of lidocaine solution depends on the type of anesthesia:

Terminal type of anesthesia involves local application of a solution (2 mg per kg of body weight), maximum 20 ml for an adult patient. The effect lasts no more than 30 minutes.
Conduction type of anesthesia. The dosage depends on the size of the area that needs to be anesthetized. Maximum dose 20 ml.
In ophthalmology, the solution is instilled into the conjunctival sac.
Epidural anesthesia – 22-30 ml of solution.
Pain relief in obstetrics and gynecology – 20-30 ml of solution.
In childhood, the dosage is determined individually (on average 3.5-4 mg per kg of weight).

To prevent the development of side effects, the solution must be administered strictly in recommended dosages. The medication Lidocaine, the instructions for use of which contains all the necessary dosages, must be prescribed after a detailed study of the anamnesis.