Clinical Drug Experience Knowledgebase

Oxedrine (Sympatol, p-synephrine) is a naturally occurring alkaloid molecule first appeared in Europe towards the end of the 1920s being sold as a drug under the brand name Sympatol. Oxedrine was then being prescribed as a remedy for a number of respiratory conditions, which include asthma, whooping cough, colds, and hay fever. More recently, synephrine gained popularity as a weight loss aid and it has become a favored component in the more popular brands of weight loss supplement stacks. This popularity can be attributed in part to the ban imposed on ephedra, to which it shares similar mechanisms of action. Most, if not all of the synephrine being sold as a dietary supplement is extracted and synthesized from the Citrus aurantium plant, more commonly known as bitter orange. Just like ephedrine, synephrine has vasoconstrictive abilities, although at a lesser potency compared to ephedrine. There is no mention of synephrine in editions of Drill's Pharmacology in Medicine later than the 3rd, nor is there any reference to synephrine in the 2012 Physicians' Desk Reference, nor in the current FDA "Orange Book". One current reference source describes synephrine as a vasoconstrictor that has been given to hypotensive patients, orally or by injection, in doses of 20–100 mg.   ^NCATS