An antipyretic (//, from anti- 'against' and pyretic 'feverish') is a substance that reduces 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 nonsteroidal anti-inflammatory drugs (NSAIDs) used primarily as analgesics (pain relievers), but which also have antipyretic properties; and paracetamol (acetaminophen), an analgesic with weak anti-inflammatory properties.
There is some debate over the appropriate use of such medications, since fever is part of the body's immune response to infection. A study published by the Royal Society claims that fever suppression causes at least 1% more influenza deaths in the United States, or 700 extra deaths per year.
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 in treating illness, including:
- NSAIDs such as ibuprofen, naproxen, ketoprofen, and nimesulide
- Aspirin, and related salicylates such as choline salicylate, magnesium salicylate, and sodium salicylate
- Paracetamol (acetaminophen)
- Metamizole, banned in over 30 countries for causing agranulocytosis
- Phenazone (antipyrine), available in combination with benzocaine as an ear drop in the US.
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, it is recommended that aspirin and combination products that contain aspirin not be given to children or teenagers during episodes of fever-causing illnesses.
Traditional use of higher plants with antipyretic properties is a common worldwide feature of many ethnobotanical cultures. In ethnobotany, a plant with naturally occurring antipyretic properties is commonly referred to as a febrifuge.
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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.
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- Reye's syndrome - Prevention
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