Afrin 4 Hour Nasal Spray (Schering-Plough
Health Care); Biomydrin (Parke-Davis); Mydfrin (Alcon);
Neo-Synephrine (Sterling Health U.S.A.); Nostril (Boehringer
ChEBI: A member of the class of the class of phenylethanolamines that is (1R)-2-(methylamino)-1-phenylethan-1-ol carrying an additional hydroxy substituent at position 3 on the phenyl ring.
L-Phenylephrine is an adrenergic α1A receptor agonist (Ki = 1.4 μM) that demonstrates selectivity against the α1B and α1C receptor subtypes (Kis = 23.9 and 47.8 μM, respectively). By stimulating adrenergic α1 receptors, L-phenylephrine can induce aortic smooth muscle contractions, although reported relative affinity and potency values in rabbit are 5-fold weaker compared to that of L-norepinephrine. This compound is frequently used to precontract smooth muscle in preparations designed to study the properties of various vasodilator agents. Because L-phenylephrine acts on adrenergic α1 receptors in the arterioles of the nasal mucosa to produce constriction, it has been examined clinically as an oral decongestant.