Halothane (Halothanum)

Pharmacodynamics Pharmacokinetics Indications Carefully Contraindications Dosing and Administration Side effects
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Clinical and pharmacological group: & nbsp

Means for anesthesia

Included in the formulation
  • Halothane
    liquid d / inhal. 
    Piramal Enterprise Limited     India
  • Fluorotane
    liquid d / inhal. 
    ALTAYHIMPROM, JSC     Russia
    • Included in the list (Order of the Government of the Russian Federation No. 2782-r of 30.12.2014):

    VED

    АТХ:

    N.01.A.B.01   Halothane

    N.01.A.B   Halogenated hydrocarbons

    Pharmacodynamics:Halothane refers to halogenated hydrocarbons; this is the only inhalation anesthetic of this class containing bromine atoms. Increases the sensitivity of GABA receptors to gamma-aminobutyric acid, the sensitivity of glycine receptors to glycine, which leads to increased inhibitory effects on the central nervous system. Suppresses the activity of N-cholinergic receptors of neurons, thus plays a role in the analgesic effect. Increases the conductivity of some types of potassium channels of leakage, which causes hyperpolarization of neurons. As a result of this, the oppression of consciousness begins. The onset of halothane occurs in 7-10 minutes. The depth of anesthesia is labile and depends on the amount of anesthetic delivered. The time to stop anesthesia occurs in 5-15 minutes. The drug also has an undefined analgesic, muscle relaxant effect and increases intracranial pressure. Reduces contractility of the myocardium and sensitizes it to catecholamines. Increases the tone of the vagus nerve.The use of catecholamines in parallel with halothane is dangerous, since it can provoke arrhythmia.
    Pharmacokinetics:Halothane has a high lipophilicity, due to this - a high apparent volume of distribution (the exact figure is not determined). It is easily absorbed and overcomes the histohematological barriers, including blood-brain and placental barriers. The minimum alveolar concentration (in oxygen) is 0.75%; blood / gas mixture distribution ratio 2.3, brain / blood 2.9, fat / blood 51, oil / gas mixture 220. In the biotransformation liver, up to 20% of the dose is exposed, mainly with the CYP2E1 isoenzyme. The main metabolite is trifluoroacetic acid, the secondary metabolites are chlorides and bromides. It is exhaled with exhaled air in unchanged form by 60-80%, the remaining 20-40% - by kidneys in the form of metabolites. Intermediates - trifluoroacetyl chloride (mutates human proteins with the formation of derivatives, which can develop an immune response - the cause of fulminant hepatonecrosis).
    Indications:Inhalation general anesthesia for large and small surgical interventions.

    As an anesthetic can be used in diseases of the respiratory system (chronic obstructive pulmonary disease, bronchial asthma and others) and diabetes mellitus.

    Has a bronchodilating effect.

    Children and adults can be used for both introductory and supportive anesthesia.

    ICD-10

    XX.Y83-Y84.Y83.9   Surgical operation, unspecified

    Contraindications:- hypersensitivity to the drug;

    - Pregnancy and lactation;

    - jaundice and other liver diseases;

    - malignant hyperthermia in the anamnesis for the administration of halothane;

    - the need for epinephrine during surgery (risk of arrhythmias);

    - pheochromocytoma, elevated catecholamine content in the blood - for the same reason;

    - a period of 3 months after a general anesthesia with halothane;

    - arterial hypotension;

    - arrhythmia.

    Carefully:Acceptance of cardiac glycosides, porphyria, narcotic and alcohol dependence.
    Pregnancy and lactation:Do not use during pregnancy! The action category for the fetus by the FDA is C. There have not been well-controlled studies on humans. In animal experiments, the drug caused teratogenic and embryotoxic effects.

    Lactation: Do not use the drug in lactation or stop breastfeeding for the period of treatment. There is no data on the penetration of the drug into breast milk.

    Dosing and Administration:Maintenance of the surgical stage of anesthesia - in a concentration of 0.5-2%; for the introduction of anesthesia, the concentration is gradually increased to 4%. The required concentration in the blood is 25%; minimal anesthetic concentration - 15% for adults; 1.08%, 0.92%, 0.64%, respectively, for infants, children under 10 years and patients older than 70 years.

    Application in elderly patients

    Use in the elderly has not been systematically studied. There is no data on the need to reduce the dosage of the drug in patients in this group, although due to age-related changes in the cardiovascular, respiratory, central nervous and other systems, this may be relevant.

    Use in children

    Allowed. To apply in dosages: induction of anesthesia - 1,5-2% of volume; Support anesthesia 0.5-2% volume depending on the selected flow rate.

    Side effects:Allergic reactions: skin rash, itching, fever, angioedema.

    On the part of the circulatory system: lowering blood pressure, bradycardia, increasing the sensitivity of the heart to catecholamines, arrhythmias.

    Respiratory system: against the background of the use of nitrous oxide may inhibit the respiratory reflex, hypoxia.

    From the side of the central nervous system (after awakening), often: dizziness, headache, meningeal symptoms, against the background of the use of suxamethonium - malignant hyperthermia; postnarcotic delirium.

    Dysfunction of the liver: jaundice, hepatitis, hepatonecrosis.

    Urinary system: impaired renal function.

    Overdose:IV stage of anesthesia, death. Treatment is symptomatic - artificial ventilation pure oxygen, artificial circulation.
    Interaction:Alcohol (chronic use) - increased need for inhalational anesthetics.

    Amiodarone - increased risk of hypotension and atropine-resistant bradycardia.

    Means that cause a decrease in blood pressure - potentiation of hypotension.

    Anticoagulants (derivatives of coumarin and indanedione) - potentiation of anticoagulant effects.

    Tricyclic antidepressants are a high risk of ventricular arrhythmias. Anti-asthma drugs (especially anticholinesterase drugs) are an antagonistic effect on neuromuscular conduction.

    β-Adrenoblockers, including those used in ophthalmology - the risk of severe prolonged hypotension.

    Nitrous oxide - reduced demand for halogenated inhalation anesthetics.

    Inductors of microsomal enzymes of the liver - an increase in the metabolism of halogenated anesthetics, an increase in hepatotoxicity.

    Catecholamines, ephedrine, levodopa, metameninol, methoxamine, other sympathomimetics - the sensitizing effect of halogenated inhalation anesthetics on the myocardium (especially halothane).

    Ketamine - an increase in the half-life of ketamine.

    Xanthine - an increased risk of arrhythmias.

    Methyldopa - reduced need for inhalational anesthetics.

    Oxytocin - a decrease in the sensitivity of the myometrium to oxytocin.

    Means that depress the central nervous system (including the drugs used to premedicate and induction of anesthesia), enhance their effect when used with halothane. Suxamethonium - increased risk of malignant hyperthermia, potentiation of muscle relaxant action.

    Aminoglycosides, freshly citrated blood, lincomycin, nondepolarizing muscle relaxants, polymyxins - carefully combined with halogenated inhalation anesthetics (risk of increased muscle weakness,respiratory depression and paralysis; treatment with anticholinesterase agents and administration of calcium ions).

    Increases the risk of liver damage when using phenytoin.

    Special instructions:The introduction of epinephrine and other sympathomimetics increases the risk of arrhythmias. It is necessary to cancel them for 6-8 hours before the onset of anesthesia. Patients with chronic alcoholism for anesthesia require large doses.

    In developed countries halothane practically does not find use because of the appearance of new and more effective drugs of this class.

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