Antipyretics (//), from the Greek anti, against, and pyreticus, pertaining to fever, are substances that reduce fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, resulting in a reduction in fever.
Most antipyretic medications have other purposes. The most common antipyretics in the United States are ibuprofen and aspirin, which are used primarily as pain relievers. Non-steroidal anti-inflammatory drugs (NSAIDs) are antipyretic, anti-inflammatory, and pain relievers.
There is some debate over the appropriate use of such medications, as fever is part of the body's immune response to infection. A study published by the Royal Society claims fever suppression causes at least 1% more influenza cases of death, resulting in at least 700 extra deaths per year in the United States alone.
Bathing or sponging with lukewarm or cool water can effectively reduce body temperature in those with heat illness but not usually in those with fever. The use of alcohol baths is not an appropriate cooling method, because there have been reported adverse events associated with systemic absorption of alcohol.
Many medications have antipyretic effects and thus are useful for fever but not heat illness, including:
- NSAIDs such as ibuprofen, naproxen, ketoprofen, and nimesulide
- Aspirin, and related salicylates such as choline salicylate, magnesium salicylate, and sodium salicylate
- Paracetamol (USAN and JAN: Acetaminophen)
- Metamizole, banned in over 30 countries for causing agranulocytosis
- Phenazone, also known as antipyrine, available in combination with benzocaine as an ear drop in the US.
Traditional use of higher plants with antipyretic properties is a common worldwide feature of many ethnobotanical cultural systems. In ethnobotany, plants with naturally occurring antipyretic properties are commonly referred to as febrifuges.
The U.S. Food and Drug Administration (FDA) notes that improper dosing is one of the biggest problems in giving acetaminophen (paracetamol) to children. The effectiveness of acetaminophen alone as an antipyretic in children is uncertain, with some evidence showing it is no better than physical methods. Therapies involving alternating doses of acetaminophen and ibuprofen have shown greater antipyretic effect than either drug alone. One meta-analysis indicated that ibuprofen is more effective than acetaminophen in children at similar doses when both are given alone.
Due to concerns about Reye syndrome, the U.K. NHS, the U.S. Centers for Disease Control and Prevention (CDC), the U.S. Surgeon General, the American Academy of Pediatrics (AAP) and the U.S. Food and Drug Administration (FDA) recommend that aspirin and combination products containing aspirin not be given to children or teenagers during episodes of fever-causing illnesses. However, the decreased use of aspirin, with the converse increased use of acetaminophen/paracetamol, has been linked to the increase in asthma and other autoimmune disorders by several studies. Physicians recommending acetaminophen/paracetamol should use caution and be especially attentive to any genetic or environmental predisposition to asthma or other autoimmune disorders.
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- Schultes, R.E.; Raffauf, R.F. De Plantis Toxicariis e Mundo Novo Tropicale Commentationes. XXXIX. Febrifuges of northwest Amazonia. Harvard Papers in Botany Vol. 5, pp. 52-68. 1994.
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- Reducing Fever in Children: Safe Use of Acetaminophen
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Trial evidence that paracetamol has a superior antipyretic effect than placebo is inconclusive.
- E. Michael Sarrell, MD; Eliahu Wielunsky, MD; Herman Avner Cohen, MD (2006). "Antipyretic treatment in young children with fever: acetaminophen, ibuprofen, or both alternating in a randomized, double-blind study". Archives of Pediatrics & Adolescent Medicine 160 (2): 197–202. doi:10.1001/archpedi.160.2.197. PMID 16461878. Retrieved 2010-09-25.
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- Reye's syndrome - Prevention
- CDC Study Shows Sharp Decline in Reye's Syndrome among U.S. Children
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