Description
Pharmacological action
Phenylephrine – a-adrenergic agonist, It has a pronounced non-selective a-adrenomimetic effect. When used in therapeutic doses, it does not have a significant stimulating effect on the central nervous system.
When applied topically in ophthalmology, it causes the expansion of the pupil, improves the outflow of intraocular fluid and narrows the vessels of the conjunctiva.
Mildly affects -adrenoreceptors, including the heart (does not have a positive chrono- and inotropic effect). The drug has a vasoconstrictor effect similar to that of norepinephrine (norepinephrine). The vasopressor effect of phenylephrine is weaker than that of norepinephrine, but is longer. It causes vasoconstriction 30-90 seconds after instillation, lasting 2-6 hours.
After instillation, phenylephrine causes contraction of the muscle that dilates the pupil, thereby causing the pupil to expand. Mydriasis occurs within 10-60 minutes after a single instillation. Mydriasis persists for 2 hours. Mydriasis caused by phenylephrine is not accompanied by cycloplegia.
Indications
Iridocyclitis (to prevent the occurrence of posterior synechia and reduce exudation from the iris).
For diagnostic dilatation of the pupil with ophthalmoscopy and other diagnostic procedures necessary to monitor the condition of the posterior segment of the eye.
Provide a provocative test in patients with a narrow anterior chamber angle profile and suspected angle-closure glaucoma.
Differential diagnosis of superficial and deep injection of the eyeball.
Syndrome of the “red eye” (to reduce hyperemia and irritation of the membranes of the eye).
Spasm of accommodation.
Use during pregnancy and lactation
There is no sufficient experience with the use of phenylephrine during pregnancy. Therefore, the use of the drug as prescribed by the attending physician during pregnancy is possible if the potential benefit to the mother outweighs the possible risk to the fetus. It is not known whether the drug is excreted in breast milk. When prescribing the drug, breastfeeding during treatment is recommended to be discontinued.
Special instructions
The mydriatic effect of phenylephrine is enhanced when used in combination with topical use of atropine. Due to increased vasopressor action, the development of tachycardia is possible.
The use of phenylephrine with monoamine oxidase inhibitors, as well as within 21 days after the cessation of their use, should be carried out with caution, since in this case there is the possibility of an uncontrolled rise in blood pressure.
The vasopressor effect of -adrenomimetics can also be potentiated with simultaneous use with tricyclic antidepressants, propranolol, reserpine, guanethidine, methyldopa and m-anticholinergics.
Phenylephrine can potentiate the inhibition of cardiovascular activity by inhalation anesthesia.
Concomitant use with other adrenomimetics and sympathomimetics may enhance the effect of phenylephrine on the cardiovascular system.
The use of phenylephrine can cause a weakening of concomitant antihypertensive therapy and lead to an increase in blood pressure, tachycardia.
Composition
Active ingredient: phenylephrine hydrochloride – 25.0 mg.
Excipients: benzalkonium chloride, in terms of anhydrous substance – 0.1 mg, disodium edetate – 1.0 mg, sodium hydroxide – 0.24 mg, sodium disulfite – 3.0 mg, citric acid monohydrate – 1.0 mg , sodium citrate dihydrate – 5.0 mg, purified water – up to 1 ml.
Dosage and Administration
Topically.
With iridocyclitis, the drug is used to prevent the development and rupture of already formed posterior synechia to reduce exudation into the anterior chamber of the eye. For this purpose, 1 drop of the drug is instilled into the conjunctival sac of a sick eye (eye) 2-3 times a day.
When performing ophthalmoscopy, a single instillation of the drug is used. Usually, instillation of 1 drop of the drug into the conjunctival sac is enough to create mydriasis. The maximum mydriasis is reached after 15-30 minutes and persists for 1-3 hours.
If it is necessary to maintain mydriasis for a long time, after 1 hour, repeated instillation of the drug is possible.
For diagnostic procedures, a single instillation of the drug is used:
– as a provocative test in patients with a narrow profile of the angle of the anterior chamber of the eye and suspected angle-closure glaucoma. If the difference between the values ??of intraocular pressure before instillation of the drug and after the expansion of the pupil is from 3 to 5 mm RT. Art., the provocative test is considered positive
– for differential diagnosis such as eyeball injection: if, after 5 minutes after the instillation of the drug, a narrowing of the vessels of the eyeball is noted, then the injection is classified as superficial, while maintaining redness of the eye, it is necessary to carefully examine the patient for iridocyclitis or scleritis, as this indicates the expansion of deeper vessels.
To relieve the spasm of accommodation in children from 6 years of age and adults, the drug is instilled 1 drop in each eye at night every day for 4 weeks.
Side effects
From the organ of vision
Conjunctivitis, periorbital edema.
In some cases, patients notice a burning sensation at the beginning of use, blurred vision, irritation, discomfort in the eye, increased lacrimation, increased intraocular pressure.
Phenylephrine may cause reactive myosis the day after administration.
Repeated instillations of the drug over a short period of time can lead to less pronounced mydriasis than previously observed. This effect is more often seen in elderly patients.
Due to a significant contraction of the muscle expanding the pupil, 30-45 minutes after instillation under the influence of phenylephrine in the moisture of the anterior chamber of the eye, particles of pigment from the pigment sheet of the iris can be detected. Suspension in chamber moisture must be differentiated with manifestations of anterior uveitis or with the formation of blood cells in the moisture of the anterior chamber.
Systemic reactions
From the skin and its appendages: contact dermatitis.
From the cardiovascular system: palpitations, tachycardia, arrhythmia, increased blood pressure, ventricular arrhythmia, reflex bradycardia, coronary artery occlusion, pulmonary embolism.
Drug Interactions
The mydriatic effect of phenylephrine is enhanced when used in combination with topical use of atropine. Due to increased vasopressor action, the development of tachycardia is possible.
The use of phenylephrine with monoamine oxidase inhibitors, as well as within 21 days after the cessation of their use, should be carried out with caution, since in this case there is the possibility of an uncontrolled rise in blood pressure.
The vasopressor effect of? -adrenomimetics can also be potentiated with simultaneous use with tricyclic antidepressants, propranolol, reserpine, guanethidine, methyldopa and m-anticholinergics.
Phenylephrine can potentiate the inhibition of cardiovascular activity by inhalation anesthesia.
Concomitant use with other adrenomimetics and sympathomimetics may enhance the effect of phenylephrine on the cardiovascular system.
The use of phenylephrine can cause a weakening of concomitant antihypertensive therapy and lead to an increase in blood pressure, tachycardia.
Overdose of
From the organ of vision
Conjunctivitis, periorbital edema.
In some cases, patients notice a burning sensation at the beginning of use, blurred vision, irritation, discomfort in the eye, increased lacrimation, increased intraocular pressure.
Phenylephrine may cause reactive myosis the day after administration.
Repeated instillations of the drug over a short period of time can lead to less pronounced mydriasis than previously observed. This effect is more often seen in elderly patients.
Due to a significant contraction of the muscle expanding the pupil, 30-45 minutes after instillation under the influence of phenylephrine in the moisture of the anterior chamber of the eye, particles of pigment from the pigment sheet of the iris can be detected. Suspension in chamber moisture must be differentiated with manifestations of anterior uveitis or with the formation of blood cells in the moisture of the anterior chamber.
Systemic reactions
From the skin and its appendages: contact dermatitis.
From the cardiovascular system: palpitations, tachycardia, arrhythmia, increased blood pressure, ventricular arrhythmia, reflex bradycardia, coronary artery occlusion, pulmonary embolism.
Storage conditions
Store in a dark place at a temperature not exceeding 25 C.
Keep out of the reach and sight of children.
Expiration
2 years.
Do not use after the expiry date stated on the pack.
Keep the dropper vial open for a maximum of 30 days.
active substance
Phenylephrine
Terms leave through pharmacies
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