/dee'keuhn jes"teuhnt/, Pharm.
1. of or pertaining to a substance that relieves mucus congestion of the upper respiratory tract.
2. any such substance.
[1945-50; DE- + CONGEST + -ANT]

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      any drug used to relieve swelling of the nasal mucosa (nose) accompanying such conditions as the common cold and hay fever. When administered in nasal sprays or drops or in devices for inhalation, decongestants shrink the mucous membranes lining the nasal cavity by contracting the muscles of blood vessel walls, thus reducing blood flow to the inflamed areas. The constricting action chiefly affects the smallest arteries, the arterioles, although capillaries, veins, and larger arteries respond to some degree.

      Decongestants are sympathomimetic agents; that is, they mimic the effects of stimulation of the sympathetic division of the autonomic nervous system. One of the chief drugs of the group is epinephrine (epinephrine and norepinephrine), a neurotransmitter produced by the adrenal gland that is released at sympathetic nerve endings when the nerves are stimulated. The effect of its decongestant action resembles the blanching of the skin that occurs with anger or fright, in which epinephrine constricts the blood vessels of the skin.

      The effectiveness of the other decongestants results from their chemical similarity to epinephrine. The oldest and most important decongestant is ephedrine, an alkaloid originally obtained from the leaves of ma huang, any of several species of shrubs of the genus Ephedra, which has been used in Chinese medicine for more than 5,000 years. Ephedrine and other decongestants are made by chemical synthesis. They include phenylephrine hydrochloride, amphetamine and several derivatives, and naphazoline hydrochloride. Because none of them has a sustained effect, they must be used repeatedly; too frequent use, however, results in absorption into the bloodstream, causing anxiety, insomnia, dizziness, headache, or heart palpitations.

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Universalium. 2010.

Look at other dictionaries:

  • decongestant — ► ADJECTIVE ▪ (of a medicine) used to relieve nasal congestion. ► NOUN ▪ a decongestant medicine …   English terms dictionary

  • decongestant — 1950, from DE (Cf. de ) + congestant (see CONGEST (Cf. congest)) …   Etymology dictionary

  • decongestant — [dē΄kənjes′tənt] n. a medication or treatment that relieves congestion, as in the nasal passages …   English World dictionary

  • Decongestant — A decongestant or nasal decongestant is a type of drug that is used to relieve nasal congestion. Contents 1 Pharmacology 2 List 3 See also 4 References …   Wikipedia

  • Decongestant — A drug that shrinks the swollen membranes in the nose and makes it easier to breath. Decongestants can be taken orally or by nasal spray. Decongestant nasal sprays should not be used for more than five days without the doctor s advice, and if so …   Medical dictionary

  • decongestant — UK [ˌdiːkənˈdʒestənt] / US [ˌdɪkənˈdʒestənt] noun [countable] Word forms decongestant : singular decongestant plural decongestants medical a drug that helps you breathe more easily when you have a cold …   English dictionary

  • decongestant — noun Date: 1947 an agent that relieves congestion (as of mucous membranes) • decongestant adjective …   New Collegiate Dictionary

  • decongestant — [[t]di͟ːkənʤe̱stənt[/t]] decongestants N MASS A decongestant is a medicine which helps someone who has a cold to breathe more easily …   English dictionary

  • decongestant — adjective (chiefly of a medicine) used to relieve nasal congestion. noun a decongestant medicine …   English new terms dictionary

  • decongestant — de•con•ges•tant [[t]ˌdi kənˈdʒɛs tənt[/t]] adj. 1) pha relieving mucus congestion of the upper respiratory tract 2) pha a decongestant agent • Etymology: 1945–50 …   From formal English to slang

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