PHENYLEPHINE HYDROCHLORIDE (Mesatonum; synonym: Isophrin, Neophryn, Neo-Synephrine, Phenylephrini Hydrochloridum, Rinisol, Tensamin, Visadron, Hemorex etc.; GF X, SP. B) — adrenomimetichesky means; 1 (m oxyphenyl) - 2 methylaminoethanols a hydrochloride; With 8 H 13 NO 2 - HCl:
Inodorous crystal powder, white or white with slightly yellowish shade. Let's easily dissolve in water and alcohol, it is almost insoluble on air; t ° pl 141 — 145 °; pier. weight (weight) 203,67. Solutions (pH 3,0 — 3,5) will sterilize at t ° 100 ° within 30 min.
M. unlike adrenaline (see) and noradrenaline (see) is not a catecholamine since contains only one hydroxyl in the meta-provision of an aromatic kernel; catechol-au-methyltransferase is not inactivated, is more resistant and works is longer.
The m stimulates preferential alpha adrenoceptors and causes narrowing of peripheral arterial vessels, raises the ABP. At the same time reflex bradycardia in this connection the minute volume of blood decreases a little and extended a diastolic pause is possible. Venous pressure slightly increases. Against the background of action atropine (see) pressor action of M. much more amplifies and followed more often by tachycardia, than bradycardia. On pressor activity of M. by 5 — 10 times concedes to adrenaline, but its pressor effect by 3 — 5 times is more long. The m causes expansion of pupils, on c. the N of page exerts the weak stimulating impact.
M. apply for increase in the ABP at the collapse and acute hypotension caused by the lowered vascular tone including at orthostatic hypotension, intoxications and hypotension. M apply also locally to vasoconstriction and reduction of inflammatory changes of mucous membranes at conjunctivitis, vasculomotor rhinitises, hay cold. In M.'s ophthalmology use in quality mydriatic means (see). Besides, M. can be used instead of adrenaline in solutions of local anesthetics.
Dosages and ways of introduction of M. choose taking into account indications to use. At acute hypotension adult M. usually enter into a vein fractionally (slowly!) in doses of 0,1 — 0,3 — 0,5 ml of 1% of solution from 40 ml of 5 — 20 — 40% of solution of glucose or kapelno on 1 ml of 1% of solution in 250 — 500 ml of 5% of solution of glucose. Under skin and intramusculary enter 1% of solution on 0,3 — 1 ml. At hypotension and in other cases of M. appoint inside 0,01 — 0,025 g 2 — 3 times a day.
To vasoconstriction and reduction of inflammatory changes from mucous membranes solutions M. apply 0,25 — 0,5% (to greasing or an instillation). As mydriatic means of M. appoint in the form of 1 — 2% of solutions (with to lay down. purposes) and 2,5% of solution (with the diagnostic purpose). To solutions of anesthetics M. add 1% of solution for 10 ml of solution of anesthetic at the rate of 0,3 — 0,5 ml.
The highest doses for adults inside: one-time 0,03 g, daily 0,15 g; under skin and intramusculary: one-time 0,01 g, daily 0,05 g; in a vein: one-time 0,005 g, daily 0,025 g.
Drug it is contraindicated at an idiopathic hypertensia and other hypertensive states, vasospasms and atherosclerosis. M.'s introduction is contraindicated also at the general anesthesia Ftorotanum, cyclopropane and chloroform in connection with danger of emergence of arrhythmias.
The m should be applied with care at a hyperthyroidism, hron, diseases of a myocardium, at elderly people.
Forms of release: powder and ampoules on 1 ml of 1% of solution. Storage: powder — in well corked banks of orange glass, an ampoule — in the place protected from light.
See also Adrenomimetichesky means .
Bibliography: Anichkov S. V. Selective effect of mediator means, page 236, L., 1974; Clinical pharmacology, under the editorship of V. V. Zakusov, page 87, M., 1979; Komissarov I. V. Medicinal regulation of adrenergic processes, Kiev, 1976, bibliogr.; The pharmacological basis of therapeutics, ed. by L. S. Goodman a. A. Gilman, p. 503, L., 1975.
G. V. Kovalyov.