I-Phrine - General Information
An alpha-adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent. [PubChem]
Pharmacology of I-Phrine
I-Phrine is a powerful vasoconstrictor. It is used as a mydriatic, nasal decongestant, and cardiotonic agent. I-Phrine is a postsynaptic alpha-receptor stimulant with little effect on the beta receptors of the heart. Parenteral administration of I-Phrine causes a rise in systolic and diastolic pressures, cardiac output is slightly decreased and peripheral resistance is considerably increased, most vascular beds are constricted; renal, splanchnic, cutaneous, and limb blood flows are reduced but coronary blood flow is increased. Pulmonary vessels are constricted, and pulmonary arterial pressure is raised. This alpha receptor sympathetic agonist is also used locally because its vasoconstrictor and mydriatic action.
I-Phrine for patients
Vasopressors, particularly metaraminol, may cause serious cardiac arrhythmias during halothane anesthesia and therefore should be used only with great caution or not at all.
The pressor effect of sympathomimetic pressor amines is markedly potentiated in patients receiving monoamine oxidase inhibitors (MAOI). Therefore, when initiating pressor therapy in these patients, the initial dose should be small and used with due caution. The pressor response of adrenergic agents may also be potentiated by tricyclic antidepressants.
Phenylephrine hydrochloride should not be used in patients with severe hypertension, ventricular tachycardia, or in patients who are hypersensitive to it or to any of the components.
Additional information about I-Phrine
I-Phrine Indication: For the treatment of ophthalmic disorders (hyperaemia of conjunctiva, posterior synechiae, acute atopic), nasal congestion, hemorrhoids, hypotension, shock, hypotension during spinal anesthesia, paroxysmal supraventricular tachycardia. It is also used as an aid in the diagnosis of heart murmurs and for prolongation of spinal anesthesia
Mechanism Of Action: I-Phrine produces its ophthalmic and systemic actions by acting on alpha 1 adrenergic receptors in the pupillary dilator muscle and the vascular smooth musle, resulting in contraction of the dilator muscle and contraction of the smooth muscle in the arterioles of the conjunctiva and peripheral vasoconstriction. I-Phrine decreases nasal congestion by acting on alpha 1 adrenergic receptors in the arterioles of the nasal mucosa to produce constriction.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Phenylephrine
Synonyms: Fenilefrina [Inn-Spanish]; L-Phenylephedrine; L-Phenylephrine; M-Methylaminoethanolphenol; M-Oxedrine; Metaoxedrinum; Metaoxedrine; Metaoxedrin; Metasynephrine; Phenylephrinum [Inn-Latin]
Drug Category: Adrenergic alpha-Agonists; Cardiotonic Agents; Nasal Decongestants; Sympathomimetics; Vasoconstrictor Agents; Mydriatics
Drug Type: Small Molecule; Approved
Absorption: Reduced bioavailability (compared to pseudoephedrine) following oral administration due to significant first-pass metabolism.
Toxicity (Overdose): Not Available
Protein Binding: 95% binding-plasma proteins
Biotransformation: Oral phenylephrine is extensively metabolised by monoamine oxidase, an enzyme which is present in the stomach and liver.
Half Life: 2.1 to 3.4 hours
Dosage Forms of I-Phrine: Solution Intravenous
Solution / drops Ophthalmic
Chemical IUPAC Name: 3-[(1R)-1-hydroxy-2-methylaminoethyl]phenol
Chemical Formula: C9H13NO2
Phenylephrine on Wikipedia: https://en.wikipedia.org/wiki/Phenylephrine
Organisms Affected: Humans and other mammals