Superficial, or terminal, anesthesia is a type of local anesthesia. To eliminate sensitivity, the patient only needs to lubricate the necessary area of the skin or mucous membranes with a special solution or inject. This method of anesthesia is widely used in dental practice, as well as in obstetrics and otolaryngology. In addition, it is used for bronchoscopy, cystoscopy, gastroscopy and laryngoscopy.
Aerosol "Lidocaine" is the most popular and inexpensive local anesthetic, which is intended for surface anesthesia. The composition of this tool, how and in what dosage it should be used and whether it has side effects, is described below.
Composition and packaging of anesthetic
What is the lidocaine analgesic spray? This product is intended for topical use. A 10% dosed preparation is available in the form of an alcoholic solution without any color, but with a characteristic menthol odor.
The active substance of the drug is lidocaine. The following auxiliary ingredients are also included in the solution: propylene glycol, peppermint leaf oil and 96% ethanol.
Aerosol "Lidocaine" goes on sale in dark glass bottles equipped with a metering pump. Also included is a spray nozzle.
Anesthetic effect
According to the attached instructions, Lidocaine Aerosol is a local anesthetic intended for terminal or surface anesthesia. The principle of operation of this tool is associated with the blockade of sodium voltage-dependent channels. Lidocaine prevents the generation of impulses in the nerve sensory endings and does not allow pain impulses to be carried along nerve fibers.
Local use of such a drug causes an analgesic effect and promotes the expansion of blood vessels, but does not have an irritating effect.
How quickly does Lidocaine Aerosol begin to work? The effect after the application of such an anesthetic develops after 1-5 minutes and lasts about an hour.
Pharmacokinetic features
What pharmacokinetic properties are inherent in the Lidocaine aerosol (10%)? According to the instructions, such a drug is quickly absorbed from the mucous membranes, especially from the respiratory tract and pharynx. The degree of absorption of lidocaine depends on several factors: the total dose of the drug, the degree of blood supply to the mucosa, the site of application and the duration of application.
When applying the drug to the mucosa of the upper respiratory tract, the solution is partially swallowed and broken down in the digestive tract. The time to reach the maximum concentration of lidocaine is 10-20 minutes (when applied to the ENT organs).
The connection of the anesthetic with plasma proteins depends on its concentration and is approximately 60-80%. The active substance of the drug is distributed quite quickly (in 6-9 minutes). First, lidocaine enters the bloodstream tissues (lungs, heart, liver, brain, spleen), and then into muscle and fat.
The medication penetrates the placental barrier and the BBB. It is also secreted with breast milk (approximately 40% of the concentration in the blood of a nursing mother).
Lidocaine metabolism occurs in the liver (about 90-95%). In this case, microsomal enzymes are involved. Metabolization is carried out by breaking the amide bond and dealkylation of the amino group, which causes the formation of less active metabolites (glycinexilidine and monoethylglycinexilidine). The half-life of the latter is 10 and 2 hours, respectively.
The excretion of lidocaine from the human body occurs along with bile and urine (unchanged up to 10%).
Pharmacokinetic features in special groups of people
What you need to know before using Lidocaine Aerosol? Patients should be aware that in the presence of any liver pathologies, the metabolic rate of the active substance of the drug is significantly reduced and is about 10-50%.
With a diagnosis of chronic renal failure, there is a likelihood of cumulation of metabolites.
Prescription of a local drug
What is the use of Lidocaine spray? The use of this tool is indicated for superficial or terminal anesthesia of the mucous membranes.
In dental practice, a medication is used in the following cases:
- when suturing mucous membranes;
- when removing tartar;
- for the purpose of anesthetizing the injection area before conducting local anesthesia;
- to remove moving teeth in children (primary teeth);
- to anesthetize the gums before fixing the bridge or crown;
- in babies, dissection of the salivary gland cyst or excision of the frenum of the tongue.
In gynecology and obstetrics, a local anesthetic is used:
- when processing the incision and episiotomy;
- when removing postpartum sutures;
- with intervention on the vagina or cervix.
For the throat, an aerosol with lidocaine (in the otorhinolaryngological practice) is prescribed for severe perspiration and pain. Also, the drug can be used in the following cases:
- during surgery on the nasal septum;
- for electrocoagulation.
With endoscopic and instrumental studies, lidocaine helps to cope with pain with:
- introduction of a probe, intubation, rectoscopy, etc .;
- X-ray examination (to eliminate pharyngeal reflex and nausea).
In surgical practice and dermatology, the drug is used:
- for superficial anesthesia of the skin with small surgeries;
- as an analgesic for small wounds (for example, with scratches) and burns (including sunburn).
Contraindications to the use of local anesthetic
Due to the fact that the drug in question is a vasodilator, for men, the Lidocaine spray is a good solution to extend the sexual intercourse. For this, representatives of the stronger sex spray the solution directly onto the mucous membrane of the genitals (in particular, on the glans penis). However, experts argue that such use of the drug can be dangerous to the health of men.
Also, lidocaine can not be used in the following cases:
- for adenotomy and tonsillectomy in children under eight years of age;
- with increased sensitivity to the active and other components of the drug.
With extreme caution, the drug is used for rectoscopy with hemorrhoidal bleeding, as well as for local infections at the site of application, trauma to the mucous membrane or skin, severe somatic pathologies, impaired cardiac conduction, epilepsy, impaired liver function, bradycardia, breastfeeding, severe shock, pregnancy, young children and elderly patients.
Aerosol "Lidocaine": instructions for use
The medication in question is used only topically and externally. The dosage of anesthetic depends on the indications and the vastness of the anesthetized area.
One dose of the spray that is released after pressing the metering valve includes 4.8 mg of the active substance.
To avoid a high concentration of lidocaine in the blood, it is necessary to use the lowest dosage that provides a positive effect. Typically, 1 or 2 sprays are sufficient for loss of sensitivity. However, in obstetrics and gynecology, 15-20 sprays (or even more) are often used. It must be remembered that the maximum dose of the drug per 70 kg of patient body weight is 40 sprays.
Recommended dosage of anesthetic for various indications:
- in gynecology - 4-5 sprays;
- during surgical interventions in the oral cavity - 1-4;
- in dentistry - 1-3;
- in obstetrics - 15-20;
- in ENT practice - 1-4;
- with endoscopy - 2-3;
- in dermatology - 1-3.
The instructions say that lidocaine can be applied to the mucous membrane and skin using a cotton swab. This application is especially effective in dental procedures and operations in children (avoids fear when spraying anesthetic).
Side effects
What negative effects can the lidocaine spray cause? For men, women and children, this drug is contraindicated if it provoked at least one of the following effects:
- urticaria, nervous agitation, transient erythema, bronchospasm, systemic dizziness, angioedema;
- insomnia, anaphylactic shock, impaired sensitivity, loss of consciousness, decreased blood pressure, respiratory paralysis, edema, inhibition of myocardial function, cardiac arrest, bradycardia.
It should also be said that after the use of lidocaine, most patients observe such a local reaction as a sensation of slight tingling. Typically, this phenomenon disappears with the onset of the anesthetic effect (lasts about 1 minute).
Overdose cases
An overdose of lidocaine causes the following symptoms: headache, increased sweating, diplopia, pallor of the skin, anxiety, dizziness, numbness, blurred vision, tremors, tinnitus, convulsions, decreased blood pressure, cardiac arrest, bradycardia, drowsiness, arrhythmia, chills, methemoglobinemia, agitation.
Therapy: with the development of intoxication (for example, with dizziness, nausea, vomiting, euphoria), further use of the drug is stopped. In this case, the patient is transferred to a horizontal position and is prescribed oxygen inhalation. Dialysis with an overdose of lidocaine is ineffective.
It's important to know!
It is extremely important not to allow the drug to enter the respiratory system, as there is a high risk of aspiration. Therefore, spraying anesthetic into the throat requires special attention.
The drug is well absorbed through the mucous membranes and damaged skin. This fact should be taken into account when treating large areas of the body in children.
Application of the drug to the mucous membrane of the cheeks carries a risk of dysphagia, as well as subsequent aspiration. In addition, with a violation of the sensitivity of the oral mucosa, the risk of biting the cheeks and tongue increases.
When using the spray during operations in the nasopharynx or pharynx, it must be taken into account that lidocaine suppresses pharyngeal and cough reflexes, therefore, falling into the larynx and trachea, it can cause bronchopneumonia.
With extreme caution, the drug in question should be applied to infected areas and damaged mucous membranes.
In children under two years of age, the medication should be used only after applying it to a cotton swab.
How should lidocaine spray be kept during local anesthesia? Reviews of experts report that for the safe and effective use of the drug in the process of spraying it, the bottle must be given a strictly vertical position. In this case, the solution should not enter the visual organs.
Precautionary measures
Aerosol must not be heated. In addition, the solution bottle should not be opened and subjected to strong shock.
In the period after the use of lidocaine, special care must be taken when driving vehicles and engaging in other potentially dangerous types of work that require quick reactions and an increased concentration of attention.