Tolazoline is a non-selective competitive α-adrenergic receptor antagonist. It is a vasodilator that is used to treat spasms of peripheral blood vessels (as in acrocyanosis). It has also been used successfully as an antidote to reverse the severe peripheral vasoconstriction which can occur as a result of overdose with certain 5-HT2A agonist drugs such as 25I-NBOMe, DOB and Bromodragonfly (prolonged severe vasoconstriction can lead to gangrene if untreated).
It is however most commonly used in veterinary medicine, to reverse xylazine-induced sedation.
Chemistry
Tolazoline can be synthesized by the heterocyclation of the ethyl ester of iminophenzylacetic acid with ethylene diamine, which forms the desired product. The structure of tolazoline is strikingly similar to α-adrenergic agonists, which are antiedema sympathomimetics.
Synthesis
tle="Tolazoline" alt="Tolazoline" style="width:400px;display:block;margin-left: auto;margin-right: auto" src="http://upload.wikimedia.org/wikipedia/commons/thumb/5/56/Tolazoline.png/800px-Tolazoline.png">
- Tetrahydrozoline