Halothane
Instructions for use:
- 1. Release form and composition
- 2. Indications for use
- 3. Contraindications
- 4. Method of application and dosage
- 5. Side effects
- 6. Special instructions
- 7. Drug interactions
- 8. Analogs
- 9. Terms and conditions of storage
- 10. Terms of dispensing from pharmacies
Halothane is a general inhalation anesthetic.
Release form and composition
Dosage form - liquid for inhalation: colorless, transparent, heavy, mobile, with a specific odor (50 and 250 ml each in glass vials of type III amber, sealed with lacquered aluminum screw caps with a first opening ring, in a cardboard box 1 bottle).
Composition of 1 bottle:
- active substance: halothane - 99.99% (v / v);
- additional component: thymol - 0.01% (v / v).
Indications for use
Halothane is used for induction and maintenance of general anesthesia in adults and children.
Contraindications
- arterial hypotension;
- hypercatecholaminemia;
- pheochromocytoma;
- myasthenia gravis;
- fever or fever after administration of halothane in history;
- unexplained jaundice;
- known or suspected genetic predisposition to malignant hyperthermia;
- carrying out dental procedures for children under 18 years old outside stationary conditions;
- I trimester of pregnancy, the period of childbirth and the early postpartum period;
- use of halothane for general anesthesia less than 3 months ago;
- hypersensitivity to the drug.
In the II and III trimesters of pregnancy, Halothane can be used only for health reasons and under strict medical supervision.
Nursing women after inhalation anesthesia should refrain from breastfeeding for 24 hours.
Method of administration and dosage
Halothane can be used for any type of inhalation anesthesia.
To avoid overdosing, the required dose is achieved using a calibration evaporator located outside the closed circulation system.
Introduction to anesthesia: at a flow rate of 8 l / min, the halothane supply begins with a concentration of 0.5 vol.% (With oxygen), then the concentration of halothane vapor in the mixture is gradually increased to 0.5–3 vol.%.
For maintenance anesthesia, a concentration of 0.5-1.5% by volume is usually sufficient.
For children for induction of anesthesia, a concentration of 1.5–2.0 vol.% Is used.
For elderly people, the dose of halothane is reduced. The actual dosage is selected based on the physical condition of the patient.
The surgical stage of anesthesia is usually reached within 4–6 minutes.
The minimum alveolar concentration (MAC) is:
- for adults: when using a mixture with oxygen - 0.77 vol.%, a mixture with nitrous oxide - 0.3 vol.%;
- for elderly people over 70 years old: when using a mixture with oxygen - 0.64 vol.%;
- for children: when using a mixture with oxygen - 1.08 vol.% (for children under 6 months), 0.92 vol.% (for children under 10 years old).
To eliminate possible hypercapnia and to more rapidly eliminate halothane at the end of the operation, the oxygen flow is increased.
Side effects
- from the cardiovascular system: arterial hypotension, cardiac arrhythmias (ventricular arrhythmias under conditions of hypoxia, bradycardia, hypercapnia);
- from the respiratory system: oppressed breathing;
- from the digestive system: impaired liver function up to the development of jaundice, liver necrosis, hepatitis (especially with repeated injections); after waking up - nausea, postoperative vomiting;
- from the side of the central nervous system: after waking up - increased intracranial pressure, tremor, headache;
- laboratory parameters: increased transaminases, eosinophilia;
- others: malignant hyperthermia.
Overdose symptoms: arrhythmia, respiratory depression, hypotension, severe bradycardia, hyperthermic crisis. Treatment: artificial ventilation of the lungs with pure oxygen and symptomatic therapy.
special instructions
In order to avoid the development of adverse reactions associated with excitation of the vagus nerve (arrhythmias or bradycardia), methocinium iodide or atropine is administered to the patient before anesthesia.
For premedication, the use of trimeperidine is considered more preferable than morphine, since it less excites the centers of the vagus nerve.
Monitoring the patient's condition in anesthesia includes monitoring the following indicators: body temperature, blood pressure, pulse, blood oxygen content (monitoring the color of the skin and mucous membranes, as well as measurement using a blood test or pulse oximeter), pupil response, blood tests for gases, urine output rate, continuous recording of electrocardiogram, monitoring of electrolyte composition and acid-base state.
Halothane causes muscle relaxation, therefore, special care should be taken with the simultaneous use of aminoglycoside antibiotics.
Also, the drug should be used with caution in patients receiving cardiac glycosides.
Patients with chronic alcoholism require large doses for anesthesia.
When performing gynecological operations, it is important to take into account that halothane can cause a decrease in the tone of the myometrium, as a result of which the risk of bleeding increases. For the same reason, in obstetric practice, the drug is used only in cases where relaxation of the uterus is indicated.
During anesthesia, an increase in intracranial pressure and / or an increase in blood flow in the vessels of the brain is possible, especially in the presence of intracranial pressure. To counteract these effects in neurosurgery, moderate hyperventilation is performed.
Patients on therapy with monoamine oxidase inhibitors should stop taking them at least 2 weeks before surgery.
Patients receiving levodopa should be discontinued 6–8 hours before general anesthesia.
Halothane must not be stored in vaporizers. The evaporator should be cleaned of drug residues and decomposition products before each use. The thymol used for stabilization does not evaporate, remains in the evaporator and stains the solution yellowish. It is highly soluble and can be removed with ether.
In some cases, Halothane can contribute to the development of malignant hyperthermia syndrome (MHS), which is a severe complication of anesthesia, often leading to cerebral edema and, as a result, death, especially in children and adolescents. Clinical manifestations of this condition: severe tachycardia, a significant decrease in blood pressure, a sharp increase in body temperature to 40–42 ° C, impaired gas exchange.
As a rule, FH is observed in patients with a hereditary predisposition to malignant hyperthermia. Body temperature rapidly rises to 42 ° C and above, generalized rhabdomyolysis and severe acidosis develop. In some individuals, the first sign of muscle damage may be trismus that develops during intubation.
Intravenous administration of dantrolene is recommended as an antidote for malignant hyperthermia.
The likelihood of developing malignant hyperthermia should be assumed in case of insufficient muscle relaxation at the beginning of anesthesia, as well as in the case of fasciculations in response to the administration of ditilin (suxamethonium).
During the day after anesthesia, patients are prohibited from driving vehicles and performing work associated with potentially dangerous mechanisms.
Drug interactions
- theophylline, sympathomimetics, dopaminomimetics (for example, levodopa): the risk of arrhythmias increases;
- ganglion-blocking agents, alpha- and beta-blockers, antipsychotic drugs, calcium channel blockers: a marked decrease in blood pressure is possible;
- phenytoin: the risk of hepatotoxic action increases;
- monoamine oxidase inhibitors: the likelihood of increased blood pressure and aggravation of the toxic effect of halothane increases;
- ketamine: the half-life of halothane increases;
- suxamethonium: the risk of developing malignant hyperthermia increases;
- morphine, chlorpromazine: the inhibitory effect of halothane on respiration is enhanced;
- polymyxins, aminoglycosides, lincomycin: neuromuscular blockade increases, apnea may develop;
- tubocurarine and other antidepolarizing muscle relaxants: their muscle relaxant effect is potentiated (their doses should be reduced);
- timolol in the form of eye drops, used before surgery: hypotension and bradycardia may develop during halothane anesthesia;
- oxytocin: there is a risk of developing sinus bradycardia, arterial hypotension, pathological atrioventricular rhythm in the mother during childbirth;
- drugs that cause uterine contraction (oxytocin, ergot alkaloids): under the influence of halothane, the sensitivity of the uterus to the action of these agents decreases.
Analogs
The analogue of Halothane is Ftorotane.
Terms and conditions of storage
Store in an upright position with a tightly closed lid out of the reach of children, protected from light at temperatures up to 25 ° C.
The shelf life is 5 years.
Terms of dispensing from pharmacies
For hospitals.
Information about the drug is generalized, provided for informational purposes only and does not replace the official instructions. Self-medication is hazardous to health!
