From Big Medical Encyclopedia

ANTIPYRETICS (synonym antipyretics) — the medicinal substances lowering body temperature at fever.

In quality. villages most widely use non-narcotic analgesics (see. Analgesic means ), the combining soothing and antiinflammatory properties.

Salicylates concern to them — acetylsalicylic acid (see), sodium salicylate (see), Salicylamidum (see); derivatives of pyrazol — pyramidon (see), analginum (see), antipyrine (see), Butadionum (see), etc.; derivatives of aniline — paracetamol (see); acetphenetidiene (see), derivatives indolacetic to - you are (indometacin); drugs mefenaminovy, hlofenaminovy and flyufenaminovy to - t. Also some other synthetic drugs, napr have febrifugal effect, phenoquin (see), and alkaloids of a number of plants — quinine (see), colchicine, aconitine.

Influence. the page on body temperature depends on its initial level. The most essential decrease in 1 hour (on 3,5 — 4,7 °) is observed at fever (febrifugal effect). Standard temperature of a body under influence. the page decreases usually no more than on 0,3 — 0,8 ° (hypothermal effect).

Action. the page at fever is not specific: they are effective both at infectious fevers, and at the fevers of a noninfectious origin caused, e.g., by overheating, an aseptic inflammation, defeats of diencephalic area of a brain the pyrogenic substances (see), etc. It. pages essentially differ from chemotherapeutic means — antibiotics, streptocides, etc., causing the expressed febrifugal effect only at infectious fevers thanks to specific (antimicrobic, antiparasitic, etc.) to action.

Decrease in body temperature at fever under influence. the page from among non-narcotic analgesics results from strengthening of processes of a thermolysis at the expense of the vasodilatation of skin and increase in sweating arising against the background of their action which are, obviously, a consequence of action. page on the Hypothalamic centers of thermal control. In an experiment non-narcotic analgesics weaken the feverish reactions arising in response to thermal irritation of the respective areas of a hypothalamus. Besides, at usual ways of introduction they warn and stop the fever caused by pyrogens at their immediate effect (application) on the temperature-controlled centers of a hypothalamus. Similar results are observed also in case of administration of non-narcotic analgesics to the same areas of a hypothalamus, and pyrogens intravenously. Administration of pyrogens together with non-narcotic analgesics in the III cerebral cavity is not followed by fervescence. The hypothesis is based on these data, according to a cut in origins of febrifugal effect under the influence of non-narcotic analgesics their antagonism in relation to the substances causing fever matters. The mechanism of febrifugal effect of non-narcotic analgesics is considered also from the point of view of their influence on education and release in an organism of prostaglandins. It is established that non-narcotic analgesics inhibit synthesis of these substances in various fabrics, including and in brain. Meanwhile it is known that prostaglandins of the E (PGE) group have the pyrogenic properties and are, obviously, «mediators» of the fever caused by nek-ry pyrogenic toxins.

Febrifugal effect of alkaloids (quinine, aconitine) depends hl. obr. from weakening of heat production owing to the oppression of oxidizing processes caused by these substances in fabrics.

. pages apply as symptomatic at various feverish states caused by overheating, thermoneuroses, defeats of diencephalic area of a brain at postvaccinal fevers, postoperative fevers which are not connected with a wound fever, etc. Expediency of broad use. the village at infectious fevers most of clinical physicians denies as these states at infectious diseases are considered as manifestation of defense reaction of an organism; besides, it is specified that immunol, processes, phagocytosis and other protective mechanisms at fever amplify. Use. the page at infectious fevers admits rational only in case of substantial increase of body temperature (40 ° above) i.e. when fever in itself can become the reason of life-threatening frustration of various systems of an organism, and also at a pyrotherapy and in case of reactions of an aggravation at chemotherapy of infectious diseases.

Bibliography: Mashkovsky M. D. Pharmaceuticals, p.1 — 2, M., 1977; The pharmacological basis of therapeutics, ed. byL. S. Goodman a. A. Gilman, L., 1975.

V. K. Muratov.