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Active ingredients
Phenylephrine
Release form
Drops
Composition
Active ingredient: phenylephrine hydrochloride Auxiliary substances: sodium citrate dihydrate, disodium edetate, citric acid, hypromellose, sodium metabisulphite, water d / injection. Active ingredient concentration (mg): 25 mg
Pharmacological effect
Sympathomimetic. It has pronounced alpha-adrenergic activity and, when used in normal doses, does not have a significant stimulating effect on the CNS. very weak effect on myocardial β-adrenoreceptors. The drug has a vasoconstrictor action, similar to the action of norepinephrine (norepinephrine), while it has virtually no chronotropic and inotropic effect on the heart. The vasopressor effect of phenylephrine is less pronounced than that of norepinephrine, but is longer. Causes vasoconstriction 30-90 seconds after instillation, the duration is 2-6 hours. After instillation, phenylephrine reduces the dilator of the pupil and the smooth muscles of the conjunctiva, thereby causing the pupil to expand. Mydriasis occurs within 10-60 minutes after a single instillation. After instillation of eye drops, 2.5% of mydriasis persists for 2 hours, after instillation of eye drops 10% - 3-7 hours. phenylephrine has a slight effect on the ciliary muscle, mydriasis occurs without cycloplegia.
Pharmacokinetics
Data on the pharmacokinetics of the drug is not provided.
Indications
For diagnostic manipulations: provision of mydriasis during ophthalmoscopy, provocative tests for closed angle glaucoma, as well as in persons with a narrow profile of the anterior chamber of the eye; differentiation of the superficial and deep injection of the eyeball; - treatment of iridocyclitis, red eye syndrome, glauco-cyclic crises, treatment of spasm of adjoins tion and true myopia in individuals with high visual load.
Contraindications
Individual hypersensitivity to the drug or drug components; - narrow-angle or angle-closure glaucoma; - cardiovascular diseases with heart rhythm disturbances, tachycardia, high blood pressure, aortic aneurysm; - additional mydriasis during operations with impaired integrity of the eyeball or decrease in total tear production; type 1 diabetes; - thyroid disease with overproduction of hormones; - lack of glucose-6-phosphate dehydrogenase; - hepatic porphyria; - breastfeeding period th - children's age.
Precautionary measures
Do not exceed recommended doses.
Use during pregnancy and lactation
Since the effect of the drug Irifrin during pregnancy and lactation has not been studied enough, the use of the drug in these patients is possible only in cases where the expected benefit of therapy for the mother outweighs the potential risk to the fetus or infant.
Dosage and administration
A single use of the drug is sufficient to achieve a sufficient pharmacological effect. Ophthalmoscopy: one time instillation of 2.5% with Irifrin’s solution locally (into the conjunctival sac), instillation may be repeated after 60 minutes in case of insufficient drug mydriasis. instillation of one drop of 2.5% p-ra. If there is a difference in intraocular pressure of three to five mm Hg. st. The provocative test is positive. In case of differentiation of the superficial and deep injection of the eyeball, 1 drop is instilled once and the results are evaluated after five minutes. With the narrowing of the vessels of the conjunctiva, the injection is considered superficial, while preserving hyperemia - this is a sign of the expansion of deep-seated vessels. Treatment of iridocyclitis (2.5%, 10% pp) and glauco-cyclic crisis (10% pp): instillation of one drop Irifrin with an interval of 8 hours, a course of treatment for up to 10 days depending on the severity of the disorder. In weak myopia, spasm of accommodation during a period of high visual load, Irifrin 2.5% is administered one drop at bedtime. With the progression of myopia - three times a day, 1 drop of Irifrin. Preoperative preparation: 10% of Irifrin solution half an hour before the operation is instilled once into the conjunctival sac. After opening the membranes of the eye, repeated instillations are not performed.
Side effects
Local side effects: inflammation and conjunctival redness, keratitis, swelling and pain in the eye, burning, tearing after instillation, increased intraocular pressure. Perhaps the development of reactive constriction of the pupil a day after instillation, which reduces the effectiveness of repeated instillations, is more typical for older people. As a result of a significant reduction in the dilator of the pupil, the appearance of pigment particles from the cells of the iris pigment leaf is observed in moisture in the anterior chamber of the eye after half an hour. And it requires differentiation with uveitis or with the penetration of blood corpuscles. Systemic side effects: Allergic reactions manifest as dermatitis. Cardiovascular changes - increased heart rate, rhythm disturbances, ventricular arrhythmias, increased blood pressure, acute circulatory disturbance in the coronary arteries, reflex bradycardia, sudden pulmonary embolus obstruction. The following disorders of the cardiovascular system increase the risk of myocardial infarction in elderly patients.
Overdose
Symptoms: manifestations of systemic action of phenylephrine. Treatment: the use of alpha-blockers (for example, 5-10 mg of fentolamine / in). If necessary, the introduction can be repeated.
Interaction with other drugs
The mydriatic effect of phenylephrine is enhanced by its use in combination with atropine. Due to increased vasopressor action, tachycardia may develop. When using Irifrin at the same time as MAO inhibitors or for 21 days after stopping their use, there is a risk of developing an uncontrolled rise in BP. Vasopressor effect of adrenomimetic drugs may also be potentiated when used together with tricyclic antidepressants, propranolol, reserpine , guanethidine, methyldopa and m-anticholinergics. Application of Irifrin in the form of 10% eye drops in combination with systemic use of beta-adrenob locators can lead to acute arterial hypertension. Irifrin may potentiate the inhibitory effect on the activity of the cardiovascular system during inhalation anesthesia. The use of synergies with sympathomimetics may enhance the cardiovascular effects of phenylephrine.
special instructions
Irifrin should be used with caution in patients with diabetes due to the risk of developing an increase in blood pressure associated with impaired vegetative regulation, as well as in elderly patients due to an increased risk of reactive miosis. Irifrin should be used with caution at the same time as MAO inhibitors, and also within 21 days after discontinuation. Exceeding the recommended dose when using eye drops 2.5% in patients with injuries, diseases of the eye or its appendages, in the postoperative period or with reduced tears products (anesthesia) can lead to increased absorption of phenylephrine and the development of systemic side effects. Due to the fact that the drug causes conjunctival hypoxia, it should be used with caution in patients with sickle cell anemia, when wearing contact lenses, after surgical interventions (reduced healing).