Phenylephrine - instructions for use, dose, side effects, contraindications

Stimulates postsynaptic alpha1-adrenoceptors. It causes a narrowing of arterioles, an increase in blood pressure (with a possible reflex bradycardia), an increase in the overall peripheral resistance of blood vessels. The action begins immediately after the introduction and lasts for 20 minutes (after intravenous administration), 50 minutes (with subcutaneous injection), 1-2 hours (after intramuscular injection). Has a slight stimulating effect on the brain and spinal cord.Reduces blood flow - renal, cutaneous, in the organs of the abdominal cavity and extremities. Narrows the pulmonary vessels and increases the pressure in the pulmonary artery.

As a vasoconstrictor has an anticongestive effect: reduces edema and hyperemia of the nasal mucosa, the severity of exudative manifestations, restores free breathing; lowers the pressure in the paranasal cavities and in the middle ear.

Stimulates postsynaptic alpha1-adrenoceptors of the radial muscle of the iris, causes its reduction. With topical application in ophthalmology causes the dilatation of the pupil, improves the outflow of intraocular fluid and narrows the vessels of the conjunctiva. After instillation phenylephrine reduces the dilator pupil, thereby causing the pupil dilated, and smooth muscle arterioles of the conjunctiva. The size of the pupil returns to its original state within 4-6 hours. Since phenylephrine has a minor effect on the ciliary muscle, mydriasis occurs without cycloplegia. Phenylephrine easily penetrates into the tissues of the eye, the pupil enlargement occurs within 10-60 minutes after a single instillation. Mydriasis persists for 4-6 hours.Due to the significant reduction of the pupil dilator, 30-45 minutes after instillation in the anterior chamber humidity may be detected by the pigment particles from the pigment leaf of the iris.

Discloses the use of phenylephrine at subdural and inhalational anesthesia (to maintain adequate blood pressure and subdural prolongation of anesthesia), anaphylaxis, paroxysmal supraventricular tachycardia, arrhythmia reperfusion (Bertsolda-Jarisch reflex), priapism, secretory prerenal anuria.

Pharmacokinetics:

After oral administration phenylephrine it is poorly absorbed from the digestive tract, therefore it is metabolized with the participation of MAO in the intestinal wall and at the first passage through the liver. Bioavailability of phenylephrine is low.

After topical application, systemic absorption is low.

Indications:

For parenteral use: acute hypotension, shock states (including traumatic shock, toxic shock syndrome), vascular insufficiency (including vasodilators background overdose), local anesthesia (as a vasoconstrictor).

In otorhinolaryngology (nasal drops, spray): to facilitate breathing through the nose - colds, flu,pollinosis or other allergic diseases of the upper respiratory tract, accompanied by acute rhinitis or sinusitis.

In ophthalmology (eye drops): iridocyclitis (to prevent the occurrence of posterior synechia and decrease exudation); dilated pupil in ophthalmoscopy and other diagnostic procedures necessary to monitor the state of the posterior segment of the eye; carrying out a provocative test in patients with a narrow anterior chamber angle profile and suspected closure angle glaucoma; differential diagnosis of the type of injection of the eyeball; in ophthalmic surgery in preoperative preparation for dilatation of the pupil (10% solution); when performing laser interventions on the fundus and vitreoretinal surgery; treatment of glaucomycyclic crises; treatment of "red eye syndrome" (2.5% solution) (to reduce hyperemia and irritation of the membranes of the eye).

ICD-10

I.A30-A49.A48.3 Toxic shock syndrome

VII.H10-H13.H10.9 Conjunctivitis, unspecified

VII.H15-H22.H20 Iridocyclitis

VII.H40-H42.H40.8 Other glaucoma

XXI.Z00-Z13.Z13.5 Special screening examination to identify eye and ear diseases

IX.I95-I99.I95 Hypotension

IX.I95-I99.I99 Other and unspecified disorders of the circulatory system

X.J00-J06.J00 Acute nasopharyngitis (runny nose)

X.J00-J06.J01 Acute Sinusitis

X.J00-J06.J06.8 Other acute upper respiratory tract infections of multiple localization

X.J10-J18.J11 Influenza, virus not identified

X.J30-J39.J30 Vasomotor and allergic rhinitis

XVIII.R50-R69.R57.9 Shock, unspecified

XIX.T79.T79.4 Traumatic shock

Contraindications:

Hypersensitivity.

Injection: hypertension (blood pressure to be monitored and the infusion rate), hypertrophic obstructive cardiomyopathy, atrial fibrillation, ventricular fibrillation, decompensated heart failure, severe atherosclerosis, severe forms of IHD, cerebral artery disease, pheochromocytoma, metabolic acidosis, hypercapnia, hypoxia, hypovolemia, acute myocardial infarction, porphyria, congenital glucose-6-phosphate dehydrogenase deficiency, age to 18 years.

Eye drops: narrow-angle or angle-closure glaucoma, advanced age for serious violations of the cardiovascular or cerebrovascular system; additional mydriasis during surgery in patients with impaired integrity of the eyeball, as well as in violation of tear production; hyperthyroidism, hepatic porphyria,congenital glucose-6-phosphate dehydrogenase deficiency, children under 12 years of age, and patients with an aneurysm of the arteries (10% solution), children with a reduced body weight (2.5% solution).

Nasal drops: diseases of the cardiovascular system (including coronarosclerosis, stenocardia), hypertensive crisis, thyrotoxicosis, diabetes mellitus.

Sprays nasal: diseases of the cardiovascular system (including severe atherosclerosis, stenocardia, tachycardia), thyroid disease (thyrotoxicosis), diabetes mellitus, hypertension, children under 6 years.

Carefully:Solution for injection: closed-angle glaucoma, hypertension in a small circle of circulation, severe stenosis of the aortic aorta, shock with myocardial infarction, tachyarrhythmia, ventricular arrhythmia, bradycardia, occlusive vascular disease (including history) - arterial thromboembolism, atherosclerosis, thromboangiitis obliterans Burger), Raynaud's disease, propensity to vascular spasms (including with frostbite), diabetic endarteritis, thyrotoxicosis, advanced age; nasal drops: children under 6 years.

Pregnancy and lactation:

Application during pregnancy and during lactation is possible only if the potential benefit to the mother exceeds the possible risk to the fetus and the baby.

Action category for the fetus by FDA - C.

Dosing and Administration:

Subcutaneously, intramuscularly, intravenously, slowly or infusion. The dosage regimen depends on the indications and the dosage form used.

For intravenous fluid administration, 10 mg is dissolved in 9 ml of water, 10 mg for intravenous infusion is added to 500 ml of a 0.9% solution of sodium chloride or 5% glucose.

Moderate hypotension: subcutaneously or intramuscularly, adults - 2-5 mg, then if necessary 1-10 mg; intravenously - 0.2 mg (0.1-0.5 mg), the interval between administrations is at least 10-15 minutes. Severe hypotension and shock - drip intravenously; the initial infusion rate is 0.18 mg / min, as the BP stabilizes, the rate is reduced to 0.04-0.06 mg / min.

As a vasoconstrictor with regional analgesia added to the anesthetic solution.

Higher doses for adults: subcutaneously or intramuscularly single dose - 10 mg, daily - 50 mg, with intravenous administration of a single dose of 5 grams, daily - 25 mg.

Eye drops: used in the form of instillations.

Intranasally, children under the age of 1 year - 1 drop in each nasal passage no more often than every 6 hours, from 1 year to 6 years - 1-2 drops, over 6 years and adults - 3-4 drops. The duration of treatment is no more than 3 days. For the spray: children 6-12 years old - 2-3 injections not more often than every 4 hours.

Side effects:

From the side cardiovascular system and blood (hematopoiesis, hemostasis): increased or decreased blood pressure, pain in the heart, palpitations, tachycardia, cardiac arrhythmias, including ventricular, arterial hypertension, reflex bradycardia, coronary artery occlusion, pulmonary artery embolism, myocardial infarction (in some cases, with use of a 10% solution of eye drops in elderly people who had cardiovascular disease).

From the side nervous system and sense organs: headache, dizziness, agitation, restlessness, irritability, weakness, sleep disturbance, tremor, paresthesia; eye drops - increased intraocular pressure, reactive myosis (the day after application, at this time, repeated instillations of the drug may produce less pronounced mydriasis than the day before, the effect is more common in elderly patients).

Other: nausea or vomiting, respiratory depression, oliguria, acidosis, skin pallor, sweating.

Local reactions: solution for injection - local ischemia of the skin at the injection site, necrosis and the formation of the scab when ingested or subcutaneously injected; eye drops - burning sensation (at the beginning of application), blurred vision, irritation, discomfort, lacrimation; nasal dosage forms: burning, tingling or tingling in the nose.

Overdose:

It is manifested by ventricular extrasystole and short paroxysms of ventricular tachycardia, a sense of heaviness in the head and extremities, a significant increase in blood pressure.

Treatment: intravenous administration of alpha-blockers (eg, phentolamine) and beta-blockers (in case of heart rhythm disturbance).

Interaction:

α-adrenoblockers, other agents with α-adrenergic blocking activity (haloperidol, phenothiazines, thioxanthenes), furosemide and other diuretics-reduction of the vasoconstrictor effect.

β-Adrenoblockers, including drugs used in ophthalmology - mutual weakening of therapeutic effects, the risk of hypertension and severe bradycardia with the possible development of heart block.

Rauwolfia alkaloids - a decrease in the hypotensive effect, lengthening of the effects of adrenomimetics.

Antianginal drugs - a decrease in the antianginal effect.

Antihypertensives - antagonism effects on blood pressure.

Diatrizoates, iotalamate, yoksaglat - enhance the neurological effects of these drugs.

Other sympathomimetic agents are an increased likelihood of side effects.

MAO inhibitors, tricyclic antidepressants, furazolidone, procarbazine, selegiline, adrenomimetics intensify the pressor effect and risk of severe ventricular arrhythmias (applied at intervals of 2-3 weeks).

Cocaine for topical application - increased stimulation of the central nervous system, the likelihood of developing a hypertensive crisis and rhythm disturbances.

Methyldopa - an increase in the pressor effect of sympathomimetics.

Cardiac glycosides, levodopa - risk of arrhythmias of the heart; if you need to simultaneously use a thorough ECG monitoring.

Means for inhalation anesthesia (derivatives of hydrocarbons) - risk of severe ventricular arrhythmias.

Thyroid hormones - potentiation of side effects of adrenomimetics, risk of coronary insufficiency.

Tricyclic antidepressants and maprotiline - heart rhythm disturbances, tachycardia, severe arterial hypertension or hyperthermia.

Ergotamine (ergot derivatives), oxytocin - risk of severe hypertension, ischemia and gangrene (vasoconstriction).

Special instructions:

During the treatment period, ECG, blood pressure, pulmonary wedge pressure, cardiac output, circulation in the extremities and at the injection site should be monitored. With arterial hypertension, it is necessary to maintain systolic blood pressure at a level of 30-40 mm Hg. below the usual. Before or during the therapy of shock conditions, correction of hypovolemia, hypoxia, acidosis, hypercapnia is mandatory. A sharp increase in blood pressure, pronounced bradycardia or tachycardia, persistent heart rhythm disturbances require discontinuation of treatment. To prevent recurrence of blood pressure after discontinuation of the drug, the dose should be reduced gradually, especially after a prolonged infusion. Infusion is resumed if systolic blood pressure drops to 70-80 mm Hg.

During therapy, potentially dangerous activities that require rapid motor and mental reactions are excluded.

When topical application after absorption through the mucosa phenylephrine can cause systemic effects.In this regard, the use of phenylephrine in the form of 10% eye drops in infants and elderly patients should be avoided. The use of a 2.5% or 10% solution of phenylephrine with MAO inhibitors, and also within 21 days after their cancellation, should be carried out with caution, since it is possible to develop systemic adrenergic effects.

Instructions

Phenylephrine (Phenylephrinum)