Decongestant
Encyclopedia
A decongestant or nasal decongestant is a type of drug
that is used to relieve nasal congestion
.
(noradrenaline) and epinephrine
(adrenaline) or adrenergic
activity by stimulating the α-adrenergic receptor
s. This induces vasoconstriction
of the blood vessel
s in the nose
, throat
, and paranasal sinuses, which results in reduced inflammation
(swelling
) and mucus
formation in these areas.
The active ingredients in most ingested decongestants are pseudoephedrine
or phenylephrine
. Decongestant nasal sprays and eye drops often contain oxymetazoline
and are used for topical decongestion
. Pseudoephedrine acts indirectly on the adrenergic receptor system, whereas phenylephrine and oxymetazoline are direct agonists. The effects are not limited to the nose, and these medicines may cause hypertension
(high blood pressure) through vasoconstriction
. But most decongestants are not pronounced stimulants due to lack of response from the other adrenoreceptors. Besides hypertension, common side-effects include sleeplessness, anxiety, dizziness, excitability, and nervousness.
Decongestants are normally paired with antihistamines to lessen this effect, but the combination of both classes of drugs does not necessarily cancel the side-effects of each other.
Topical nasal or ophthalmic decongestants quickly develop tachyphylaxis
(a rapid decrease in the response to a drug after repeated doses over a short period of time). Long-term use is not recommended, since these agents lose effectiveness after a few days.
Decongestants uncommon, discontinued, or both, include:
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
that is used to relieve nasal congestion
Nasal congestion
Nasal congestion is the blockage of the nasal passages usually due to membranes lining the nose becoming swollen from inflamed blood vessels. It is also known as nasal blockage, nasal obstruction, blocked nose, stuffy nose, or stuffed up nose.Nasal congestion has many causes and can range from a...
.
Pharmacology
The vast majority of decongestants act via enhancing norepinephrineNorepinephrine
Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...
(noradrenaline) and epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
(adrenaline) or adrenergic
Adrenergic
An adrenergic agent is a drug, or other substance, which has effects similar to, or the same as, epinephrine . Thus, it is a kind of sympathomimetic agent...
activity by stimulating the α-adrenergic receptor
Adrenergic receptor
The adrenergic receptors are a class of metabotropic G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline and adrenaline ....
s. This induces vasoconstriction
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
of the blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s in the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
, throat
Throat
In vertebrate anatomy, the throat is the anterior part of the neck, in front of the vertebral column. It consists of the pharynx and larynx...
, and paranasal sinuses, which results in reduced inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
(swelling
Swelling (medical)
In medical parlance, swelling is the transient enlargement or protuberance in the body and may include tumors. According to cause, it may be congenital, traumatic, inflammatory, neoplastic or miscellaneous....
) and mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
formation in these areas.
The active ingredients in most ingested decongestants are pseudoephedrine
Pseudoephedrine
Pseudoephedrine is a sympathomimetic drug of the phenethylamine and amphetamine chemical classes. It is used as a nasal/sinus decongestant and stimulant, or as a wakefulness-promoting agent....
or phenylephrine
Phenylephrine
Phenylephrine is a selective α1-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil, and to increase blood pressure...
. Decongestant nasal sprays and eye drops often contain oxymetazoline
Oxymetazoline
Oxymetazoline 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...
and are used for topical decongestion
Topical decongestant
Topical decongestants are decongestants applied directly to the nasal cavity. By applying them directly to the site of action, topical decongestants relieve nasal congestion while reducing the side effects associated with systemically-acting decongestants, such as high blood pressure...
. Pseudoephedrine acts indirectly on the adrenergic receptor system, whereas phenylephrine and oxymetazoline are direct agonists. The effects are not limited to the nose, and these medicines may cause hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(high blood pressure) through vasoconstriction
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
. But most decongestants are not pronounced stimulants due to lack of response from the other adrenoreceptors. Besides hypertension, common side-effects include sleeplessness, anxiety, dizziness, excitability, and nervousness.
Decongestants are normally paired with antihistamines to lessen this effect, but the combination of both classes of drugs does not necessarily cancel the side-effects of each other.
Topical nasal or ophthalmic decongestants quickly develop tachyphylaxis
Tachyphylaxis
Tachyphylaxis is a medical term describing a decrease in the response to a drug due to previous exposure to that drug. Increasing the dose of the drug may be able to restore the original response. In this context tachyphylaxis is a synonym for drug tolerance...
(a rapid decrease in the response to a drug after repeated doses over a short period of time). Long-term use is not recommended, since these agents lose effectiveness after a few days.
List
Common decongestants include:- EphedrineEphedrineEphedrine is a sympathomimetic amine commonly used as a stimulant, appetite suppressant, concentration aid, decongestant, and to treat hypotension associated with anaesthesia....
- Levo-methamphetamine
- NaphazolineNaphazolineNaphazoline is the common name for 2--2-imidazoline hydrochloride. It is a sympathomimetic agent with marked alpha adrenergic activity. It is a vasoconstrictor with a rapid action in reducing swelling when applied to mucous membrane...
- OxymetazolineOxymetazolineOxymetazoline 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...
- PhenylephrinePhenylephrinePhenylephrine is a selective α1-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil, and to increase blood pressure...
- PhenylpropanolaminePhenylpropanolaminePhenylpropanolamine , also known as the stereoisomers norephedrine and norpseudoephedrine, is a psychoactive drug of the phenethylamine and amphetamine chemical classes which is used as a stimulant, decongestant, and anorectic agent. It is commonly used in prescription and over-the-counter cough...
- PropylhexedrinePropylhexedrinePropylhexedrine is a stimulant drug related to methamphetamine. It is used mainly to provide temporary symptomatic relief of nasal congestion due to colds, allergies and allergic rhinitis...
- PseudoephedrinePseudoephedrinePseudoephedrine is a sympathomimetic drug of the phenethylamine and amphetamine chemical classes. It is used as a nasal/sinus decongestant and stimulant, or as a wakefulness-promoting agent....
- SynephrineSynephrineSynephrine is a drug commonly used for weight loss. While its effectiveness is widely debated, synephrine has gained significant popularity as an alternative to ephedrine, a related substance which has been made illegal or restricted in many countries due to health risks and its use as a precursor...
- TetrahydrozolineTetrahydrozolineTetrahydrozoline, a derivative of imidazoline, is found in over-the-counter eye drops and nasal sprays. Other derivatives include naphazoline, oxymetazoline, and xylometazoline. Poisoning can result from an overdose....
Decongestants uncommon, discontinued, or both, include:
- CafaminolCafaminolCafaminol is a vasoconstrictor of the xanthine class used as a nasal decongestant in Germany....
- CyclopentamineCyclopentamineCyclopentamine is a sympathomimetic alkylamine, classified as a vasoconstrictor...
- EpinephrineEpinephrineEpinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
- FenoxazolineFenoxazolineFenoxazoline is a nasal preparation....
- LevonordefrinLevonordefrinLevonordefrin , also known as α-methylnorepinephrine , is a sympathomimetic amine used as a topical nasal decongestant and vasoconstrictor in dentistry...
- MephentermineMephentermineMephentermine is a cardiac stimulant. It was formerly used in Wyamine nasal decongestant inhalers and before that as a stimulant in psychiatry.It has been used as a treatment for hypotension.-References:...
- MetizolineMetizolineMetizoline is a nasal preparation....
- NorepinephrineNorepinephrineNorepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...
- TramazolineTramazolineTramazoline is a chemical that is used in the form of tramazoline hydrochloride in nasal decongestant preparations. It causes hypertension.- Product names :Australia* Spray-Tish * RhinasprayAustria* RhinorixBelgium* RhinosprayCzech Republic...
- TuaminoheptaneTuaminoheptaneTuaminoheptane is a nasal decongestant drug which is a sympathomimetic stimulant and vasoconstrictor. However, it can cause skin irritation, which limits its usefulness as a nasal decongestant...
- TymazolineTymazolineTymazoline is a nasal preparation....