ingredient information
Oxymetazoline Hydrochloride
xymetazoline is a selective alpha-1 agonist and partial alpha-2 agonist topical decongestant, used in the form of Oxymetazoline hydrochloride, in products such as Afrin, Dristan, Nasivin, Logicin, Vicks Sinex, Visine L.R., Sudafed OM, and Zicam. It was developed from xylometazoline at E. Merck Darmstadt by Fruhstorfer in 1961. Oxymetazoline is generally available as a nasal spray. Contents [hide] 1 Clinical uses 2 Mechanism of action 3 Side-effects and special considerations 3.1 Rebound congestion 3.2 Effects of benzalkonium chloride 3.3 Use in pregnancy 3.4 Overdose 3.5 Blood Pressure 4 Chemistry 5 References [edit] Clinical uses Oxymetazoline is available over-the-counter as a topical decongestant in the form of oxymetazoline hydrochloride in nasal sprays such as Afrin, Sudafed OM, Dristan, Dimetapp, Vicks Sinex, Zicam, and Mucinex Full Force.[1] It was developed from xylometazoline at E. Merck Darmstadt by Fruhstorfer in 1961.[2] Oxymetazoline is also used to treat epistaxis[3][4] and eye redness due to minor irritation (marketed as Visine L.R. in the form of eye drops).[5] [edit] Mechanism of action Oxymetazoline is an adrenomimetic that nonselectively agonizes a1 and a2 adrenergic receptors.[6] Since vascular beds widely express a1 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 a2 receptors; systemic application of a2 agonists, in contrast, causes vasodilation because of centrally-mediated inhibition of sympathetic tone via presynaptic a2 receptors.[7] 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.[8] [edit] Side-effects and special considerations [edit] Rebound congestion It is recommended that oxymetazoline not be used for more than three days, as rebound congestion, or rhinitis medicamentosa, may occur.[9] Patients that continue to use oxymetazoline beyond this point may become reliant on the medication to relieve their chronic congestion. Whereas this is true, patients that suffer from the abnormal swelling of turbinates that cannot be treated by surgery have been using xylometazoline and oxymetazoline permanently since they became available without side-effects. [edit] Effects of benzalkonium chloride Some studies have found that benzalkonium chloride, a common additive to oxymetazoline nasal sprays, may damage nasal epithelia and exacerbate rhinitis medicamentosa. However, the majority of studies find benzalkonium chloride to be a safe preservative.[10] [edit] Use in pregnancy The Food and Drug Administration places oxymetazoline in category C, indicating risk to the fetus cannot be ruled out. While it has been shown that a single dose does not significantly alter either maternal or fetal circulation,[11] this subject has not been studied extensively enough to draw reliable conclusions. [edit] Overdose If accidentally ingested, standard methods to remove unabsorbed drugs should be considered. There is no specific antidote for oxymetazoline, although its pharmacological effects may be reversed by alpha adrenergic antagonists such as phentolamine. In children, oxymetazoline may produce profound central nervous system depression due to stimulation of central alpha-2 receptors and imidazoline receptors, much like clonidine[citation needed]. [edit] Blood Pressure While Oxymetazoline is a non-selective alpha agonist and does increase blood pressure when used systemically, when used in moderate doses via direct nasal application, the net raise should be small or insignificant. Ingesting or using an excessive amount of the drug intra-nasally would however cause the drug to eventually be absorbed into the blood stream and would hypothetically cause an increase in blood pressure. Hypertensive patients are recommended to seek the advice of their physician before using. [edit] Chemistry Oxymetazoline is synthesized by chloromethylation of 6-tert-butyl-2,4-dimethylphenol and the further transformation of the resulting chloromethyl derivative into a nitrile.[12][13] The reaction of this with ethylene diamine gives oxymetazoline.