Antipyretics (//, from anti- 'against' and pyretic 'feverish') 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, which results 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 non-steroidal anti-inflammatory drugs (NSAIDs) used primarily as analgesics (pain relievers), but which also have antipyretic properties; and acetaminophen (paracetamol), an analgesic with weak anti-inflammatory properties.
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, which would result 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 (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.
In popular culture
- "Definition of antipyretic". Merriam-Webster Online Dictionary. Retrieved 2007-12-19.
- "Acetaminophen," National Center for Biotechnology Information, U.S. National Library of Medicine. Modified 2016-08-07, Accessed 2016-08-16.
- "Mayo Clinic".
- "Medline Plus".
- Kupferschmidt, Kai (2014-01-21). "Fight the Flu, Hurt Society?". ScienceNow.
- "UpToDate Inc".
- Sullivan, J. E.; Committee On, H. C.; Sullivan, J. E.; Farrar, H. C. (2011). "Fever and Antipyretic Use in Children". Pediatrics. 127 (3): 580–587. doi:10.1542/peds.2010-3852. PMID 21357332.
- 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.
- Biren N. Shah and Avinash K. Seth Medicinal Plants as a Source of Anti-Pyretic Agents – A Review http://scholarsresearchlibrary.com/aasr-vol2-iss3/AASR-2010-2-3-188-195.pdf
- Reducing Fever in Children: Safe Use of Acetaminophen
- Meremikwu M, Oyo-Ita A (2002). Meremikwu MM, ed. "Paracetamol for treating fever in children". Cochrane Database Syst Rev (2): CD003676. doi:10.1002/14651858.CD003676. PMID 12076499.
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.
- Kauffman, Ralph; Sawyer, L.A.; Scheinbaum, M.L. (1992). "Antipyretic Efficacy of Ibuprofen vs Acetaminophen". Am J Dis Child. 146 (5): 622–625. doi:10.1001/archpedi.1992.02160170102024.
- Reye's syndrome - Prevention
- CDC Study Shows Sharp Decline in Reye's Syndrome among U.S. Children
- Varner, A. E.; Busse, W. W.; Lemanske, R. F. (1998). "Hypothesis: Decreased Use of Pediatric Aspirin Has Contributed to the Increasing Prevalence of Childhood Asthma". Annals of Allergy, Asthma & Immunology. 81 (4): 347–351. doi:10.1016/S1081-1206(10)63127-4. PMID 9809499.