Mepifrine

Mepifrin contains the component mepivacaine hydrochloride, a local amide anesthetic with a rapid onset of anesthetic action. This effect is associated with short-term suppression of cardiac conduction and neuronal conduction within motor, autonomic, and sensory fibers.

Used in dental surgeries. The analgesic effect develops very quickly – after 1-3 minutes – and is very pronounced. Good local tolerance is also noted. [ 1 ]

Indications Mepifrine

It is used for conduction or infiltration dental anesthesia.

It is used in case of simple operations to remove teeth, during preparation of the oral cavity and treatment of the dental stump for restoration and installation of orthopedic systems.

It is especially recommended for people who cannot use vasoconstrictor substances.

Release form

The release of the therapeutic element is realized in the form of injection liquid, inside carpules or ampoules, having a volume of 1.7 ml - 10 carpules or 5 ampoules inside a cellular pack. Inside the box there are 5 packs with carpules or 2 packs with ampoules.

Pharmacodynamics

The drug works by blocking stress-dependent Na channels in the neural fiber wall. The substance initially passes through the nerve wall as a base, but is only activated as the mepivacaine cation after re-protonation.

In cases of low pH (for example, within inflamed areas), only a small particle is present in the base form, which may weaken the analgesic effect. [ 2 ]

The duration of the effect in the case of pulpal anesthesia is at least 20-40 minutes, and in the case of soft tissue anesthesia - in the range of 45-90 minutes.

Pharmacokinetics

Mepivacaine is absorbed in large volumes and at high speed. The protein binding index is in the range of 60-78%. The half-life is about 2 hours.

The distribution volume of the administered substance is 84 ml, and the clearance rate is 0.78 l/minute.

Metabolic processes of mepivacaine are carried out inside the liver; excretion of metabolic components is carried out by the kidneys.

Dosing and administration

It is prescribed exclusively for anesthesia during dental procedures.

To achieve the necessary pain-relieving effect, it is necessary to use the minimum amount of the substance capable of providing such an effect. For an adult, such a dosage is usually within 1-4 ml.

For a child over 4 years of age weighing 20-30 kg, portions are prescribed within the range of 0.25-1 ml; for a child weighing 30-45 kg – within the range of 0.5-2 ml.

Elderly people may have an increased plasma level of Mepifrin due to poor distribution and weak metabolic processes. The probability of accumulation of the substance increases especially in the case of repeated/additional injections. A similar effect may be observed in the case of systemic weakening of the patient and exacerbation of liver/renal dysfunction. In this case, it is necessary to reduce the dosage (use the minimum volume that provides the required anesthesia). The portion sizes of the drug for people with certain pathologies (angina or arteriosclerosis) are reduced according to the same scheme.

For an adult, the maximum permissible dose is 4 mg/kg. In this case, a person weighing 70 kg can be administered no more than 0.3 g of mepivacaine (10 ml of medicinal solution).

For a child over 4 years old, the dose is selected taking into account his weight and age, as well as the duration of the procedure. It is forbidden to administer more than 4 mg/kg of the drug.

Usage diagram.

Special reusable syringe cartridges are used for the procedure. Before administering the medicine, the carpule plug, which is pierced with an injection needle, must be wiped with alcohol for disinfection.

It is prohibited to treat ampoules or carpules with any solutions. Also, it is prohibited to mix the injection liquid with other drugs inside the same syringe.

To prevent the introduction of a substance into a vessel, a thorough aspiration test must be performed; however, it must be taken into account that a negative result of such a test does not guarantee the absence of the possibility of accidental entry into the vessel.

The medicine is administered at a rate of no more than 0.5 ml per 15-second interval (corresponding to 1 ampoule/carpule per minute).

Many common manifestations associated with accidental intravascular injection of drugs can be prevented by performing the injection correctly: after aspiration, 0.1-0.2 ml of Mepifrin is injected at low speed, and then (after at least 20-30 seconds) the remainder of the substance is slowly applied.

If there is any solution left inside the ampoule/carpule after the procedure, it should be disposed of. It is prohibited to use the remains of the medicinal liquid for other patients.

• Application for children

Should not be administered to persons under 4 years of age.

Use Mepifrine during pregnancy

Clinical testing of mepivacaine during pregnancy has not been conducted. Animal testing does not allow us to determine the effect of the substance on the course of pregnancy, fetal development, the process of birth, and postnatal development.

Mepivacaine can cross the placenta. There is a possibility that when mepivacaine is administered in the first trimester, the risk of fetal malformations may increase, so it is used in the early stages of pregnancy only when other local anesthetics cannot be used.

There is no information regarding the volumes of the drug excreted in breast milk. If it is necessary to use Mepifrin during lactation, breastfeeding can be resumed approximately 24 hours after its use.

Contraindications

Among the contraindications:

• the presence of severe intolerance to local amide anesthetics;
• history of malignant hyperthermia;
• severe AV conduction disorders in which a pacemaker is not used;
• epilepsy that cannot be controlled by medication;
• having a decompensated form of acute respiratory distress syndrome;
• intermittent porphyria in the active phase;
• very low blood pressure readings.

Side effects Mepifrine

Negative symptoms developing in the central nervous system.

Manifestations include headaches, tremors, CNS depression or stimulation, speech or swallowing disorder, euphoria, metallic taste, anxiety and nervousness. In addition, yawning, tinnitus, decreased consciousness, anxiety, dizziness and tremor are observed, as well as logorrhea, drowsiness, decreased vision, nystagmus and diplopia. Feelings of cold/heat/numbness, convulsions, seizures and disturbances of consciousness are possible, as well as decreased and cessation of the respiratory process, loss of consciousness and a comatose state.

In the event of such disorders, the patient is placed horizontally, oxygen ventilation is performed, and in addition, his condition is constantly monitored to prevent deterioration of the situation (the appearance of convulsions with further suppression of the central nervous system). Symptoms of agitation may be short-term or not appear at all; in this case, the first manifestation may be drowsiness, turning into fainting and cessation of the respiratory process. Often, the development of drowsiness after the use of mepivacaine is considered an early symptom of an increase in the blood index of the drug, which develops due to too rapid absorption.

Disorders of the cardiovascular system.

Often, there is suppression of the cardiovascular system, which causes bradycardia, a decrease in blood pressure, which can provoke collapse, as well as insufficiency of the cardiovascular system, which can cause cardiac arrest. In addition, the following clinical symptoms are possible: cardiac conduction disorder (AV block), tachycardia and cardiac arrhythmia (ventricular extrasystole or fibrillation). Such signs can provoke cardiac arrest.

Such manifestations of suppression of the cardiovascular system are often associated with vasovagal action, especially when the patient is in a standing position. But sometimes such disorders arise due to the effect exerted by the drug. If prodromal symptoms (dizziness, changes in pulse readings, sweating and weakness) are not recognized immediately, a seizure, progressive cerebral hypoxia or severe dysfunction of the cardiovascular system may develop.

If blood flow is insufficient or ancillary procedures may require IV infusion and (in the absence of contraindications) the use of vasoconstrictor agents (eg, ephedrine), if needed.

Respiratory disorders.

Tachypnea, and also bradypnea, which can cause apnea.

Manifestations of allergies.

Allergy symptoms with mepivacaine are usually rare and associated with severe intolerance. These include urticaria, anaphylactoid reactions, rash, swelling, fever, Quincke's edema, and anaphylaxis. As with other local anesthetics, anaphylactic symptoms are rare. Symptoms may occur suddenly and in an active form; they are often not related to the dosage. Local swelling or edema may occur.

Problems with the gastrointestinal tract.

Vomiting or nausea develops.

If side effects occur, the use of local anesthetic should be discontinued.

Overdose

Intoxication due to overdose of local anesthetic can develop in two cases: immediately, if there was an accidental intravascular injection, or later, if an excessively large dose of the drug was administered. Such negative manifestations take the form of dysfunction of the cardiovascular system or central nervous system.

Among the signs associated with the influence of the active ingredient mepivacaine:

• CNS lesions: mild disturbances – tachypnea, restlessness, metallic taste, anxiety, dizziness and tinnitus. More severe disturbances – muscle cramps or convulsions, respiratory paralysis, drowsiness, tremors and coma;
• active cardiovascular lesions: bradycardia, decreased blood pressure, cardiac arrest and cardiac conduction disorders;
• active disorders associated with the gastrointestinal tract: vomiting or nausea.

If negative symptoms occur, the administration of local anesthetic should be discontinued.

Respiratory, intravenous, and oxygen access, as well as blood flow, must be monitored and maintained. If the patient develops myoclonus, oxygenation and injection of a benzodiazepine should be performed.

If blood pressure increases, the patient's upper body should be raised vertically and, if necessary, nifedipine should be administered sublingually.

If convulsions occur, the patient must be monitored to ensure that he does not get injured, and, if necessary, diazepam must be administered intravenously.

When the blood pressure level decreases, the patient is placed horizontally, and, if necessary, an intravascular infusion of saline solution is performed and vasoconstrictor agents are administered (intravenous cortisone or epinephrine).

In case of bradycardia, atropine is used intravenously.

If the patient develops anaphylaxis, medical assistance should be called, and until it arrives, intravenous saline solutions should be administered. If necessary, cortisone and epinephrine should be administered intravenously.

In case of cardiac shock, it is necessary to raise the upper part of the patient's body to a vertical position and call for medical help.

If the cardiovascular system stops functioning, indirect cardiac massage, artificial ventilation, and resuscitation actions are performed. In addition, an ambulance must be called.

Interactions with other drugs

Agents that block the activity of Ca channels and β-adrenoblockers potentiate the suppression of myocardial contraction and conduction. When using sedatives to reduce the feeling of fear, it is necessary to reduce the dosage of Mepifrin, since it, like sedative drugs, has a suppressive effect on the central nervous system.

The use of anticoagulants may increase the risk of bleeding.

People taking antiarrhythmic drugs may experience an increase in adverse reaction symptoms when using mepivacaine.

Toxic synergism may occur when the drug is used with sedatives, ether, central anesthetics, thiopental and chloroform.

Storage conditions

Mepifrin should be stored in a place closed to children. Do not freeze the medicine. Temperature indicators - no more than 25 ° C.

Shelf life

Mepifrin is allowed to be used within a 3-year period from the date of sale of the medicinal product.

Analogues

Analogues of the drug are the substances Mepivastezin, Ultracaine with Bucaine hyperbar, Emla and Articaine, as well as Omnicaine with Brilocaine-adrenaline, Lidocaine hydrochloride and Versatis.