Description of the active substance:
This information is a reference and it is not enough that the drug has been prescribed by a doctor ..
PHARMACHOLOGIC EFFECT
Means for inhalation anesthesia. Inhaled sevoflurane for introductory anesthesia causes rapid loss of consciousness, which is quickly restored after anesthesia ceases.
Introductory anesthesia is accompanied by minimal excitation and signs of irritation of the upper respiratory tract and does not cause excessive secretion in the tracheobronchial tree and stimulation of the central nervous system. Sevoflurane (as well as other powerful agents for inhalation anesthesia) causes a dose-dependent suppression of respiratory function and a decrease in blood pressure. In humans, the threshold level of sevoflurane, which determines the development of arrhythmias under the action of epinephrine (adrenaline), was comparable to that of isoflurane and exceeded the threshold level of halothane.
Sevoflurane has a minimal effect on intracranial pressure and does not reduce the response to CO 2 . Does not have a clinically significant effect on liver or kidney function and does not cause an increase in renal or hepatic insufficiency. Does not affect the concentration of the kidneys, even with prolonged anesthesia (up to about 9 hours).
The minimum alveolar concentration (MAC) is the concentration at which 50% of patients do not have a motor reaction in response to a single stimulus (cut of the skin). MAQ of sevoflurane in oxygen is 2.05% in an adult at the age of 40 years. MAK sevoflurana, like other halogenated drugs, decreases with age and with the addition of nitric oxide.
PHARMACOKINETICS
The low solubility of sevoflurane in the blood provides a rapid increase in alveolar concentration when administered to anesthesia and a rapid decrease after discontinuation of inhalation. The ratio of alveolar concentration and concentration in the inhaled mixture to the accumulation phase 30 minutes after the inhalation of sevoflurane is 0.85. In the elimination phase, the ratio of alveolar concentrations 5 minutes after the inhalation of sevoflurane is 0.15.
The rapid removal of sevoflurane from the lungs minimizes the metabolism of sevoflurane. In humans less than 5% of the absorbed dose of sevoflurane is metabolized with the participation of the CYP2E1 isoenzyme to form hexafluoroisopropanol, the release of inorganic fluorine and carbon dioxide (or one carbon dioxide). The resulting hexafluoroisopropanol is rapidly conjugated with glucuronic acid and excreted in the urine. Other ways of metabolism of sevoflurane are not established.Sevoflurane is the only fluorinated volatile agent for anesthesia that is not metabolized to trifluoroacetic acid.
The concentration of fluoride ions depends on the duration of anesthesia, the concentration of sevoflurane added and the composition of the mixture for anesthesia.
Barbiturates do not cause defluorination of sevoflurane.
INDICATIONS
Introductory and supportive general anesthesia in adults and children in surgical operations inpatient and outpatient settings.
DOSING MODE
Means for premedication should be selected by an anesthesiologist individually.
When administered to anesthesia, the dose is individually selected and titrated until the desired effect is achieved, taking into account the age and condition of the patient. For administration to a general anesthetic, sevoflurane can be used in oxygen or in a mixture of oxygen and nitric oxide.
Prior to surgical interventions in adults and children, inhalation of sevoflurane at a concentration of up to 8% usually provides administration to a general anesthetic for less than 2 minutes.
The required level of general anesthesia can be maintained by inhaling sevoflurane at a concentration of 0.5-3% in combination with or without nitric oxide.
With age, the MAC decreases. The average concentration of sevoflurane providing the MAK of a patient aged 80 years is approximately 50% of that of a patient aged 20 years.
SIDE EFFECT
From the central nervous system and the peripheral nervous system: agitation, drowsiness after coming out of general anesthesia, dizziness; in isolated cases after sevoflurane application, short-term convulsions were noted. Although after cessation of filing of sevoflurane, consciousness is usually restored after a few minutes, nevertheless, the state of intellectual capacity for 2-3 days after anesthesia has not been studied. Within a few days after the application of sevoflurane (as well as other means for anesthesia), slight changes in mood can be noted.
On the part of the respiratory system: dose-dependent respiratory depression, increased coughing, respiratory disorders (apnea after intubation, laryngospasm).
From the cardiovascular system: dose-dependent depression of cardiac activity, reduction or increase in blood pressure, bradycardia, tachycardia.
On the part of the digestive system: nausea, vomiting, increased salivation; in some cases - transient violations of liver function.
Allergic reactions: in some cases - rash, hives, itching, bronchospasm, anaphylactic or anaphylactoid reactions.
On the part of laboratory indicators: a transient increase in the level of glucose and the number of leukocytes is possible.
Other: chills, fever.
In predisposed patients, powerful means for inhalation anesthesia, including sevoflurane, can cause a state of skeletal muscle hypermetabolism, which leads to an increase in their oxygen demand and the development of a clinical syndrome known as malignant hyperthermia. The first sign of this syndrome is hypercapnia, and clinical symptoms may include muscle rigidity, tachycardia, tachypnea, cyanosis, arrhythmias and / or unstable blood pressure. Some of these nonspecific symptoms may also occur with mild anesthesia, acute hypoxia, hypercapnia, and hypovolemia. Later, kidney failure may develop (monitor and, if possible, maintain diuresis).
Most adverse reactions are mild or moderate and transient.
CONTRAINDICATIONS
A confirmed or suspected genetic predisposition to the development of malignant hyperthermia; increased sensitivity to sevoflurane or other halogenated preparations.
PREGNANCY AND LACTATION
Adequate and strictly controlled studies of the safety of sevoflurane during pregnancy have not been conducted. Application in pregnancy is possible only in cases of extreme necessity.
It is not known whether sevoflurane is excreted in breast milk. Use with caution during lactation (breastfeeding).
APPLICATION FOR FUNCTIONS OF THE LIVER
Use with caution in case of impaired renal function.
APPLICATION IN ELDERLY PATIENTS
With age, the MAC decreases. The average concentration of sevoflurane providing the MAK of a patient aged 80 years is approximately 50% of that of a patient aged 20 years.
SPECIAL INSTRUCTIONS
They are used with caution in cases of impaired renal function, with neurosurgical interventions, if the patient has a threat of increased intracranial pressure (in combination with measures aimed at reducing intracranial pressure, such as hyperventilation).
Sevoflurane can be used only by physicians with experience in general anesthesia. It is necessary to have equipment ready for restoring airway patency, artificial lung ventilation, oxygen therapy and resuscitation.
The level of general anesthesia can change easily and quickly, therefore, only specially calibrated evaporators should be used to supply sevoflurane. With deepening of general anesthesia, the increase in arterial hypotension and suppression of respiratory function is noted.
With maintenance anesthesia, increasing the concentration of sevoflurane causes a dose-dependent decrease in blood pressure. Excessive fall in blood pressure can be associated with deep general anesthesia; in such cases it can be increased by decreasing the concentration of the sevoflurane fed.
As with any means for general anesthesia in patients with IHD, it is necessary to maintain stable hemodynamics in order to avoid myocardial ischemia.
Patients leaving general anesthesia should be carefully observed before transport to the department.
In the treatment of malignant hyperthermia, the withdrawal of drugs that caused its development, intravenous administration of dantrolene sodium, and maintenance of symptomatic therapy are indicated.
Impact on the ability to drive vehicles and manage mechanisms
Patients should be informed that, for some time after anesthesia, the ability to perform work that requires a quick reaction, such as driving a car or using potentially dangerous mechanisms, may be impaired.
DRUG INTERACTION
It is assumed that benzodiazepines and opioid analgesics reduce MAQ of sevoflurane.
MAK sevoflurana decreases with simultaneous application of nitric oxide.
Sevoflurane has an effect on the intensity and duration of the neuromuscular blockade caused by nondepolarizing muscle relaxants. With the introduction of sevoflurane as an adjunct to anesthesia with alfentanil / N 2 O, the effects of pancuronium, vecuronium and atracurium are enhanced. With the appointment of these muscle relaxants in combination with sevoflurane their doses should be adjusted in the same way as with isoflurane. The effect of sevoflurane on the effect of succinylcholine and the duration of action of depolarizing muscle relaxants has not been studied.
Because the increase in the effect of muscle relaxants is observed a few minutes after the onset of inhalation of sevoflurane, a decrease in the dose of muscle relaxants during the initial anesthesia may lead to a delay in intubation of the trachea or inadequate muscle relaxation.
Among non-depolarizing drugs, the interaction of sevoflurane with vecuronium, pancuronium and atracurium has been studied. Although there are no specific recommendations for their use, nevertheless, with endotracheal intubation, doses of nondepolarizing muscle relaxants should not be reduced; while maintaining anesthesia, doses of nondepolarizing muscle relaxants should probably be lower than with N 2 O narcosis / opioid analgesics. Additional doses of muscle relaxants are administered taking into account the response to nerve stimulation.
