Vasoconstrictor(redirected from pressor)
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one of a group of pharmacological agents that cause the constriction of the smooth muscles of blood vessels, which results in a narrowing of vascular lumens and an increase in arterial pressure and resistance to blood flow.
A distinction is made between vasoconstrictors with central action and those with peripheral action. Vasoconstrictors with central action stimulate the centers of the nervous regulation of vascular tone. The principal representatives of these neural stimulants are caffeine, strychnine, korazole, cordiamin, and camphor. Vasoconstrictors with peripheral action primarily include substances that excite the adrenergic receptors of blood vessels; these substances include epinephrine, norepinephrine, Mezaton (Adrianol), and ephedrine. Myotropic agents, for example, vasopressin and angiotensin, constitute a special group of vasoconstrictors with peripheral action. Astringents also have a local vasoconstrictive effect.
Vasoconstrictors are used to treat collapse; locally, they are used to halt bleeding and, in laryngological practice, to diminish inflammatory phenomena.