Mezaton is a drug with alpha-adrenomimetic, vasoconstrictor action.
Release form and composition
Mezaton is produced in the form of a solution for injection: a clear, colorless liquid (in 1 ml ampoules, 10 ampoules in a carton box).
The composition of 1 ml of solution includes:
- Active ingredient: phenylephrine - 10 mg (in the form of hydrochloride);
- Auxiliary components: glycerin, water for injection.
Indications for use
Parenteral Mezaton is prescribed if the following indications:
- Vascular insufficiency (including in case of an overdose of vasodilators);
- Shock conditions (including toxic, traumatic);
- Local anesthesia (as a vasoconstrictor).
Intranasal drug is used for allergic and vasomotor rhinitis.
- Hypertrophic obstructive cardiomyopathy;
- Ventricular fibrillation;
- Hypersensitivity to the drug.
Mezaton should be used with caution in elderly patients, patients under the age of 18 years (efficacy and safety of the drug in this age group of patients have not been established), during general anesthesia (fluorotan), simultaneously with monoamine oxidase inhibitors, as well as in the following diseases / conditions :
- Metabolic acidosis;
- Angle-closure glaucoma;
- Atrial fibrillation;
- Hypertension in the pulmonary circulation, arterial hypertension;
- Tachyarrhythmia, acute myocardial infarction, ventricular arrhythmia;
- Severe aortic stenosis;
- Occlusive vascular diseases (including a history of) - Raynaud's disease, atherosclerosis, arterial thromboembolism, thromboangiitis obliterans, vascular tendency to spasms (including after frostbite);
- Diabetic endarteritis;
- Renal dysfunction;
- Deficiency of glucose-6-phosphate dehydrogenase.
Nursing and pregnant women Mezaton can be used with caution (under the supervision of a doctor and only according to strict indications), assessing the balance of benefits and risks.
Dosing and Administration
Mezaton is used intravenously, intramuscularly, subcutaneously.
During the collapse of the drug is injected intravenously in a stream of slowly 0.1-0.3-0.5 ml of 1% solution, diluted in 20 ml of 0.9% sodium chloride solution or 5% dextrose solution. If necessary, the introduction can be repeated.
With intravenous drip of 1 ml of 1% solution diluted in 250-500 ml of 5% dextrose solution.
For subcutaneous or intramuscular administration, Mezaton is used: adults - 2-3 times a day, 0.3-1 ml of 1% solution; children from 15 years old (during spinal anesthesia with arterial hypotension) - 0.5-1 mg / kg.
Higher doses for adults:
- Intravenous administration: single - 5 mg daily 25 mg;
- Intramuscular and subcutaneous administration: single - 10 mg daily 50 mg.
When conducting local anesthesia, add 0.3-0.5 ml of 1% solution of mezaton per 10 ml of anesthetic solution.
If necessary, narrowing the vessels of the mucous membranes and reducing the severity of inflammatory processes, the drug is used for instillation or lubrication (the possible concentration of the solution is 0.125%, 0.25%, 0.5%, 1%).
During therapy may develop disorders of the various systems of the body:
- Central nervous system: dizziness, insomnia, cramps, fear, anxiety, paresthesia, weakness, tremor, headache, brain hemorrhage;
- Cardiovascular system: heartbeat, high blood pressure, ventricular fibrillation, bradycardia, arrhythmia, cardialgia;
- Other: ischemia of the skin at the injection site, pale skin of the face; in rare cases - necrosis and the formation of a scab in subcutaneous injections or in contact with tissue, allergic reactions.
During the period of therapy, it is necessary to monitor the ECG, blood pressure, minute blood volume, blood circulation at the injection site and in the limbs.
Before or during the treatment of shock conditions, it is necessary to correct hypoxia, hypovolemia, acidosis and hypercapnia.
In patients with arterial hypertension with medical collapse, systolic blood pressure is sufficient to maintain at a level lower than the usual at 30-40 mm Hg.
With the development of severe bradycardia, a sharp increase in blood pressure, tachycardia and persistent violations of heart rhythm, treatment should be interrupted.
To prevent re-lowering of blood pressure after the abolition of Mezaton, the dose should be reduced gradually, especially after prolonged infusion.
If systolic blood pressure drops to 70-80 mmHg, infusion should be resumed.
It should be borne in mind that the use of vasoconstrictors during labor for the correction of arterial hypotension or as an addition to local anesthetic drugs against the background of means that stimulate labor activity (ergotamine, vasopressin, methylergometrine, ergometrine) in the postpartum period may result in a persistent increase in blood pressure.
With age, the number of adrenoreceptors that are sensitive to phenylephrine decreases. Monoamine oxidase inhibitors can cause vomiting, headaches, hypertensive crisis and arrhythmias, therefore, when patients take monoamine oxidase inhibitors in the previous 2-3 weeks, the dose of sympathomimetics should be reduced.
During the use of Mezaton, it is not advisable to engage in hazardous activities that require quick mental and motor responses (including driving).
With the simultaneous use of mezaton with certain drugs, undesirable effects may occur:
- Diuretics and antihypertensive drugs (mecamylamine, methyldopa, guanadrel, guanethidine): reduction of their antihypertensive effect;
- Oxytocin, monoamine oxidase inhibitors (procarbazine, furazolidone, selegilin), tricyclic antidepressants, ergot alkaloids, adrenostimulants, methylphenidate: increased pressor effect and arrhythmogenicity of phenylephrine;
- Phenothiazines, alpha-blockers (phentolamine), furosemide and other diuretics: a decrease in the hypertensive effect;
- Reserpine: development of arterial hypertension;
- Beta-blockers: a decrease in cardiac stimulating activity;
- Oxytocin, ergometrine, methylergometrine, ergotamine, doxapram: an increase in the severity of the vasoconstrictor effect;
- Nitrates: reduced antianginal effect; reduction of the sympatomimetic pressor effect and the risk of arterial hypotension (depending on the achievement of the required clinical effect, simultaneous use is possible);
- Inhalation anesthetics (enflurane, chloroform, isoflurane, halothane, methoxyflurane): an increased risk of developing severe atrial and ventricular arrhythmias;
- Thyroid hormones: mutual enhancement of effects and the associated risk of developing coronary insufficiency (especially in coronary atherosclerosis).
Terms and conditions of storage
Store in a dark, out of reach of children at a temperature up to 25 ° C.
Shelf life - 3 years.