Mesaton^® (Solution) Instructions for Use

ATC Code

C01CA06 (Phenylephrine)

Active Substance

Phenylephrine (Rec.INN registered by WHO)

Clinical-Pharmacological Group

Alpha-adrenergic agonist

Pharmacotherapeutic Group

Alpha-adrenomimetic

Pharmacological Action

Alpha1-adrenergic stimulant, with little effect on the beta-adrenergic receptors of the heart; it is not a catecholamine (contains only one hydroxyl group in the aromatic nucleus). It causes constriction of arterioles and an increase in blood pressure (with possible reflex bradycardia). Compared to norepinephrine and epinephrine, it increases blood pressure less sharply but acts for a longer duration (less susceptible to the action of catechol-O-methyltransferase); it does not cause an increase in minute volume of blood.

The action begins immediately after administration and lasts for 5-20 minutes (after intravenous administration), 50 minutes (with subcutaneous administration), 1-2 hours (after intramuscular administration).

Pharmacokinetics

It is metabolized in the liver and gastrointestinal tract (without the involvement of catechol-O-methyltransferase). It is excreted by the kidneys in the form of metabolites.

Indications

Parenterally

• Arterial hypotension;
• Shock states (including traumatic, toxic);
• Vascular insufficiency (including against the background of vasodilator overdose);
• As a vasoconstrictor during local anesthesia.

Intranasally

• Vasomotor and allergic rhinitis.

ICD codes

Dosage Regimen

Solution

Intravenously slowly, for collapse – 0.1-0.3-0.5 ml of a 1% solution, diluted in 20 ml of a 5% dextrose solution or 0.9% sodium chloride solution. If necessary, the administration is repeated.

Intravenously drip – 1 ml of a 1% solution in 250-500 ml of a 5% dextrose solution.

Subcutaneously or intramuscularly, for adults – 0.3-1 ml of a 1% solution 2-3 times a day; for children over 15 years with arterial hypotension during spinal anesthesia – 0.5-1 mg/kg.

For constriction of the vessels of the mucous membranes and reduction of inflammatory phenomena, lubricate or instill (solution concentrations – 0.125%, 0.25%, 0.5%, 1%).

For local anesthesia, add 0.3-0.5 ml of a 1% solution per 10 ml of anesthetic solution.

Maximum doses for adults: subcutaneously and intramuscularly: single – 10 mg, daily – 50 mg; intravenously: single – 5 mg, daily – 25 mg.

Adverse Reactions

From the cardiovascular system increased blood pressure, palpitations, ventricular fibrillation, arrhythmia, bradycardia, cardialgia.

From the central nervous system dizziness, feeling of fear, insomnia, anxiety, weakness, headache, tremor, paresthesia, convulsions, cerebral hemorrhage.

Other pallor of the facial skin, skin ischemia at the injection site, in isolated cases, necrosis and scab formation are possible if it enters the tissues or with subcutaneous injections, allergic reactions.

Contraindications

• Hypersensitivity to the drug;
• Hypertrophic obstructive cardiomyopathy;
• Pheochromocytoma;
• Ventricular fibrillation.

With caution

Metabolic acidosis, hypercapnia, hypoxia, atrial fibrillation, closed-angle glaucoma, arterial hypertension, hypertension in the pulmonary circulation, hypovolemia, severe aortic stenosis, acute myocardial infarction, tachyarrhythmia, ventricular arrhythmia, occlusive vascular diseases (including in the anamnesis) – arterial thromboembolism, atherosclerosis, obliterating thromboangiitis (Buerger’s disease), Raynaud’s disease, tendency of blood vessels to spasms (including frostbite), diabetic endarteritis, thyrotoxicosis, diabetes mellitus, porphyria, glucose-6-phosphate dehydrogenase deficiency, concomitant use of monoamine oxidase inhibitors, during general anesthesia (with halothane), impaired renal function, elderly age, age under 18 years (efficacy and safety not established).

Use in Pregnancy and Lactation

Adequate and strictly controlled studies in humans and animals on the effect of the drug on pregnant women have not been conducted, data on the excretion of the drug into breast milk are not available, based on which, during pregnancy and the period of breastfeeding, the use of the drug is possible with caution, only for strict indications and under medical supervision, assessing the benefit-risk ratio.

Use in Renal Impairment

Use with caution in patients with impaired renal function.

Pediatric Use

Use with caution in children under 18 years of age (efficacy and safety not established).

Geriatric Use

Use with caution in elderly patients.

Special Precautions

During treatment, ECG indicators, blood pressure, minute volume of blood, circulation in the extremities and at the injection site should be monitored.

In patients with arterial hypertension in the case of drug-induced collapse, it is sufficient to maintain systolic blood pressure at a level 30-40 mm Hg below the usual level.

Before starting or during therapy for shock states, correction of hypovolemia, hypoxia, acidosis, and hypercapnia is mandatory.

A sharp increase in blood pressure, pronounced bradycardia or tachycardia, persistent heart rhythm disturbances require discontinuation of treatment.

To prevent a repeated decrease in blood pressure after drug withdrawal, the dose should be reduced gradually, especially after a long infusion.

The infusion is resumed if systolic blood pressure decreases to 70-80 mm Hg.

It should be borne in mind that the use of vasoconstrictors during childbirth to correct arterial hypotension or as additives to local anesthetics against the background of agents stimulating labor (vasopressin, ergotamine, ergometrine, methylergometrine) can lead to a persistent increase in blood pressure in the postpartum period.

With age, the number of adrenoreceptors sensitive to phenylephrine decreases. Monoamine oxidase inhibitors, increasing the pressor effect of sympathomimetics, can cause headaches, arrhythmia, vomiting, hypertensive crisis, therefore, in patients taking monoamine oxidase inhibitors in the previous 2-3 weeks, the doses of sympathomimetics should be reduced.

Effect on the ability to drive vehicles and mechanisms

During therapy, one should not engage in hazardous activities requiring speed of motor and mental reactions (including driving a car).

Overdose

Symptoms ventricular extrasystole, short paroxysms of ventricular tachycardia, feeling of heaviness in the head and extremities, significant increase in blood pressure.

Treatment intravenous administration of alpha-adrenergic blockers (phentolamine) and beta-adrenergic blockers (for cardiac rhythm disorders).

Drug Interactions

Mesaton^® reduces the antihypertensive effect of diuretics and antihypertensive drugs (methyldopa, mecamylamine, guanadrel, guanethidine).

Phenothiazines, alpha-adrenergic blockers (phentolamine), furosemide and other diuretics reduce the hypertensive effect.

Monoamine oxidase inhibitors (furazolidone, procarbazine, selegiline), oxytocin, ergot alkaloids, tricyclic antidepressants, methylphenidate, adrenergic stimulants enhance the pressor effect and arrhythmogenicity of phenylephrine.

Beta-adrenergic blockers reduce the cardiotonic activity; against the background of reserpine – arterial hypertension is possible (as a result of depletion of catecholamine stores in adrenergic endings, sensitivity to adrenomimetics increases). Inhalational anesthetics (chloroform, enflurane, halothane, isoflurane, methoxyflurane) increase the risk of severe atrial and ventricular arrhythmia, as they sharply increase the sensitivity of the myocardium to sympathomimetics.

Ergometrine, ergotamine, methylergometrine, oxytocin, doxapram increase the severity of the vasoconstrictor effect.
It reduces the antianginal effect of nitrates, which, in turn, can reduce the pressor effect of sympathomimetics and the risk of arterial hypotension (simultaneous use is possible depending on the achievement of the necessary therapeutic effect).

Thyroid hormones increase (mutually) the effect and the associated risk of coronary insufficiency (especially with coronary atherosclerosis).

Storage Conditions

Store in a place protected from light and out of the reach of children at a temperature not exceeding 25°C (77°F).

Shelf Life

Shelf life – 3 years.

Dispensing Status

The drug is dispensed by prescription.

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.