Oxymetazoline (OMZ)

Oxymetazoline is synthesized by chloromethylation of 6-tert-butyl-2,4-dimethylphenol and the further transformation of the resulting chloromethyl derivative into a nitrile. The reaction of this with ethylene diamine gives oxymetazoline. Oxymetazoline is a sympathomimetic that selectively agonizes α1 and partially α2 adrenergic receptors. Since vascular beds widely express α1 receptors, the action of oxymetazoline results in vasoconstriction. In addition, the local application of the drug also results in vasoconstriction due to its action on endothelial postsynaptic α2 receptors; systemic application of α2 agonists, in contrast, causes vasodilation because of centrally-mediated inhibition of sympathetic tone via presynaptic α2 receptors. Vasoconstriction of vessels results in relief of nasal congestion in two ways: First, it increases the diameter of the airway lumen; second, it reduces fluid exudation from postcapillary venules.