Phenylephrine
Systematic (IUPAC) name
3-(1-hydroxy-2-methylamino-ethyl)phenol
Identifiers
CAS number	59-42-7 61-76-7 (hydrochloride)
ATC code	C01CA06 R01AA04, R01AB01, R01BA03, S01FB01, S01GA05
PubChem	6041
DrugBank	APRD00365
Chemical data
Formula	C9H13NO2
Mol. mass	167.205 g/mol
Pharmacokinetic data
Bioavailability	38% through GI tract
Protein binding	95%
Metabolism	Hepatic (monoamine oxidase)
Half life	2.1 to 3.4 hours
Excretion	?
Therapeutic considerations
Pregnancy cat.	B3(AU) C(US) Image File history File links Phenylephrine structure. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In chemistry, hydrochlorides are salts resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (mostly amines). ... The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. ... A section of the Anatomical Therapeutic Chemical Classification System. ... A section of the Anatomical Therapeutic Chemical Classification System. ... A section of the Anatomical Therapeutic Chemical Classification System. ... A section of the Anatomical Therapeutic Chemical Classification System. ... A section of the Anatomical Therapeutic Chemical Classification System. ... A section of the Anatomical Therapeutic Chemical Classification System. ... PubChem is a database of chemical molecules. ... The DrugBank database available at the University of Alberta is a unique bioinformatics and cheminformatics resource that combines detailed drug (i. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... This article is about the chemistry of hydrogen. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Atomic mass 14. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... The molecular mass (abbreviated MM) of a substance, formerly also called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... In pharmacology, bioavailability is used to describe the fraction of an administered dose of medication that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. ... Many drugs are bound to Blood plasma proteins. ... Drug metabolism is the metabolism of drugs, their biochemical modification or degradation, usually through specialized enzymatic systems. ... The liver is an organ in some animals, including vertebrates (and therefore humans). ... Monoamine oxidase Monoamine oxidases (singular abbreviation MAO) (EC 1. ... It has been suggested that Effective half-life be merged into this article or section. ... Excretion is the process of eliminating waste products of metabolism and other materials that are of no use. ... The pregnancy category of a pharmaceutical agent is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother during pregnancy. ... Anthem: Advance Australia Fair Royal anthem: God Save the Queen Capital Canberra Largest city Sydney Official languages English (de facto 1) Government Constitutional monarchy (federal)  - Queen Elizabeth II  - Governor-General Michael Jeffery  - Prime Minister John Howard Independence from the UK   - Constitution 1 January 1901   - Statute of Westminster 11 December 1931... Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic  - President George Walker Bush (R)  - Vice President Dick Cheney (R) Independence from...
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Routes	Oral, intranasal, ophtalmic

Phenylephrine or neosynephrine is an α-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil and, rarely, to increase blood pressure. Phenylephrine has recently been marketed as a substitute for pseudoephedrine, (e.g. Pfizer's Sudafed PE) but there are recent claims that oral phenylephrine may be no more effective as a decongestant than placebo. ^[1] In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body 1. ... The adrenergic receptors (or adrenoceptors) are a class of G-protein coupled receptors that is the target of catecholamines. ... Agonists An agonist is a substance that binds to a receptor and triggers a response in the cell. ... A decongestant is a broad class of drugs designed to symptomatically treat ailments affecting the respiratory system. ... The human eye The pupil is the central transparent area (showing as black). ... A sphygmomanometer, a device used for measuring blood pressure. ... Pseudoephedrine (commonly abbreviated as PSE) is a sympathomimetic amine commonly used as a decongestant. ... Pfizer, Incorporated (NYSE: PFE) (pronounced faɪzəɹ or faɪzÉ™), is the worlds largest pharmaceutical company. ...

Uses

Decongestant

Phenylephrine is used as a decongestant, available as an oral medicine or as a nasal spray. Phenylephrine is now the most common over-the-counter (OTC) decongestant; oxymetazoline is a more common nasal spray. ^{[citation needed]} Pseudoephedrine was historically more common, although its notoriety as a methamphetamine precursor has led some governments to restrict its sale. Over-the-counter substances, also abbreviated OTC, are drugs and other medical remedies that may be sold without a prescription and without a visit to a medical professional, in contrast to prescription only medicines (POM). ... Oxymetazoline is a topical decongestant used, in the form of Oxymetazoline hydrochloride, in products such as Vicks Sinex and Afrin. ... Pseudoephedrine (commonly abbreviated as PSE) is a sympathomimetic amine commonly used as a decongestant. ... Methamphetamine (dextro-N-α-dimethyl-phenethylamine or desoxyephedrine and popularly shortened to crystal meth or ice [2] or simply meth) is an N-methylated analog of amphetamine hydrochloride. ...

Oral phenylephrine is extensively metabolised by monoamine oxidase [1], an enzyme which is present in the gastrointestinal tract and the liver. Therefore, compared to orally-taken pseudoephedrine, it has a reduced and variable bioavailability of only up to 38 percent [2] [3], and is therefore less effective as a nasal decongestant. Because phenylephrine is a direct selective alpha-adrenergic receptor agonist, it does not cause the release of endogenous noradrenaline like pseudoephedrine does. Therefore, phenylephrine is less likely to cause side-effects like central nervous system stimulation, insomnia, anxiety, irritability and restlessness. Overview of the citric acid cycle The citric acid cycle, one of the central metabolic pathways in aerobic organisms. ... Monoamine oxidase Monoamine oxidases (singular abbreviation MAO) (EC 1. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... The gastrointestinal tract (GI tract), also called the digestive tract, alimentary canal, or gut, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. ... In pharmacology, bioavailability is used to describe the fraction of an administered dose of medication that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. ... Agonists for muscle type see Agonist (muscle) An agonist is a substance that binds to a receptor and triggers a response in the cell. ... Norepinephrine (INN) or noradrenaline (BAN) is a catecholamine and a phenethylamine with chemical formula C8H11NO3. ... A diagram showing the CNS: 1. ... Insomnia is characterized by an inability to sleep and/or inability to remain asleep for a reasonable period. ... This article includes a list of works cited but its sources remain unclear because it lacks in-text citations. ...

Some popular cold remedies containing phenylephrine: Canada's hot lemon Neocitran, the United Kingdom's Lemsip, and the United States' Alka-Seltzer Cold Effervescent formula, Sudafed PE Non-Drowsy Nasal Decongestant, Robitussin CF, Tylenol Sinus, and DayQuil Capsules. // Acute viral nasopharyngitis, often known as the common cold, is a mild viral infectious disease of the upper respiratory system (nose and throat). ... NeoCitran is medication used to releave cold, flu and sinus symptoms. ... Lemsip is a well-known manufacturer of cold and flu remedies in the United Kingdom and Australasia. ... Cherry Alka Seltzer dissolving in water Alka-Seltzer is a brand name owned by the German Bayer Corporation for a line of medications sold over the counter and taken by means of rapidly dissolving tablets that form an effervescent solution in water. ... Sudafed is a brand name and registered trademark for a family of over-the-counter (OTC) decongestants based on pseudoephedrine hydrochloride and manufactured by Pfizer Inc. ... Robitussin is a brand of cold and cough medicines produced by Wyeth Consumer Healthcare. ... Vicks DayQuil is a medicine designed to help relieve many symptoms of a cold that is to be taken orally in either liquid or LiquiCap (capsule) form, during the day. ...

As a nasal spray, phenylephrine is available in 1% and 1/2% concentrations. It suffers some rebound congestion effects, although to a lesser degree than oxymetazoline.

Mydriatic

Phenylephrine is used as an eye drop to dilate the pupil to facilitate visualization of the retina. It is often used in combination with tropicamide. Narrow angle glaucoma is a contraindication to phenylephrine use. Tropicamide (troe-PIK-a-mide) is an acetylcholine receptor blocker. ... In medicine, a contraindication is a condition or factor that increases the risk involved in using a particular drug, carrying out a medical procedure or engaging in a particular activity. ...

Vasopressor

Phenylephrine is sometimes used as a vasopressor to increase the blood pressure in unstable patients with hypotension. Such use is more common in anesthesia practices; phenylephrine is especially useful in counteracting the hypotensive effect of epidural and subarachnoid anesthetics . Vasopressor is a drug used to constrict the arteries and increase blood pressure. ... In physiology and medicine, hypotension refers to an abnormally low blood pressure. ... The term epidural is often short for epidural anesthesia, a form of regional anesthesia involving injection of drugs through a catheter placed into the epidural space. ... Anesthesia (AE), also anaesthesia (BE), is the process of blocking the perception of pain and other sensations. ...

Side effects

The primary side effect of phenylephrine is hypertension. Patients with congestion and hypertension are typically advised to avoid products containing phenylephrine. For other forms of hypertension, see Hypertension (disambiguation). ...

Pregnancy

Phenylephrine is in the FDA pregnancy category C. The pregnancy category of a pharmaceutical agent is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother during pregnancy. ...

Legal issues

Pseudoephedrine and phenylephrine are both used as decongestants; and until recently, pseudoephedrine was much more commonly available in the United States. This has changed because provisions of the Combat Methamphetamine Epidemic Act of 2005 placed restrictions on the sale of pseudoephedrine products to prevent the clandestine manufacture of methamphetamine. Since 2004, phenylephrine has been increasingly marketed as a substitute for pseudoephedrine; some manufacturers have changed the active ingredients of products to avoid the restrictions on sales. ^[2] Phenylephrine has been off patent for a long time; there are many generic brands available. Pseudoephedrine (commonly abbreviated as PSE) is a sympathomimetic amine commonly used as a decongestant. ... The Combat Methamphetamine Epidemic Act of 2005 (CMEA) was signed into United States law on March 9, 2006 to regulate, among other things, retail over-the-counter sales of ephedrine, pseudoephedrine, and phenylpropanolamine products. ... Clandestine chemistry generally refers to chemistry carried out in illegal drug laboratories, but can include any kind of laboratory operation carried on in secret because of the illegality of its activities. ... Methamphetamine (dextro-N-α-dimethyl-phenethylamine or desoxyephedrine and popularly shortened to crystal meth or ice [2] or simply meth) is an N-methylated analog of amphetamine hydrochloride. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... A patent is a set of exclusive rights granted by a state to a patentee (the inventor or assignee) for a fixed period of time in exchange for the regulated, public disclosure of certain details of a device, method, process or composition of matter (substance) (known as an invention) which...

Questions about effectiveness

Pharmacists Leslie Hendeles and Randy Hatton of the University of Florida suggested in 2006 that oral phenylephrine is ineffective as a decongestant at the 10mg dose used, arguing that the studies used for the regulatory approval of the drug in the United States in 1976 were inadequate to prove effectiveness at the 10mg dose and safety at higher doses, ^[3] Other pharmacists have expressed concerns over phenylephrine's effectiveness as a nasal decongestant ^[1] and other clinicians have indicated concern for regulatory actions that reduce the availability of pseudoephedrine. ^{[4] [5]} A subsequent metaanalysis by the same researchers concluded that there is insufficient evidence for its effectiveness. ^[6] The matter is still under debate, though the Food and Drug Administration has stood by its 1976 approval. ^[2] The University of Florida (Florida or UF) is a public land-grant research university located in Gainesville, Florida. ... The Food and Drug Administration (FDA) is an agency of the United States Department of Health and Human Services and is responsible for regulating food (humans and animal), dietary supplements, drugs (human and animal), cosmetics, medical devices (human and animal) and radiation emitting devices (including non-medical devices), biologics, and...

References

1. ^ ^{a b} UFL press release on the Hendles letter
2. ^ ^{a b} Hilenmeyer, K. All stuffed up Southwest Florida Herald-Tribune (30 January 2007)
3. ^ Heldeles, L. and Hatton, R. Oral phenylephrine: An ineffective replacement for pseudoephedrine? Journal of Allergy and Clinical Immunology, Volume 118, Issue 1, Pages 279-280
4. ^ Eccles, R. Phenylephrine an ineffective replacement for pseudoephedrine in response to the methamphetamine problem in the USA. bmj.com. (May 2006)
5. ^ Eccles, R. Substitution of phenylephrine for pseudoephedrine as a nasal decongeststant. An illogical way to control methamphetamine abuse. British Journal of Clinical Pharmacology 63. p10. (January 2007)
6. ^ Hatton, R.C. et al. Efficacy and Safety of Oral Phenylephrine: A Systematic Review and Meta-Analysis Annals of Pharmacotherapy (published online Jan 2007)

See also

• Drugs.com - Phenylephrine
• MedlinePlus DrugInfo uspdi-202460