Should antipyretic therapy be used at all?
A fever is a natural response to infections, toxins, immunologic diseases or injury in many a warm-blooded animal (1p58). It can help enhance immune system function and filtering out of infection through phagocytosis (1p58). The elevated temperature also can interfere with bacteria's ability to grow and reproduce (1p58).
"Goods" of Antipyretic Therapies
A fever should max out at 105 degrees Fahrenheit, but if it reaches 106 degrees then a potential malfunctioning hypothalamus means it's time to go to the emergency medical care (1p58). The fever is to the point that cranial pressure is posing a risk to the brain, the heat may interfere with cardiac function in compromised patients, and the elevated core temperature could hurt a fetus if pregnant (1p58).
It's time to intervene with antipyretic therapy. Wet cloths, cool blankets, ice baths and cold IVs all help to offset the elevated temperature (1p59). Drugs like aspirin, or acetylsalicylic acid), and acetaminophen work by inhibiting prostaglandin production in the hypothalamus blocking their signals and effectively reducing the body's temperature set point to that of near normal levels (1p59).
"Bads" of Antipyretic Therapies
Aspirin and acetaminophen all are blockers of cyclooxygenase (COX) activity (1pp40-41). There are two isoforms of COX. COX-1 maintains the the gastric mucosa, regulates perfusion in the kidneys and is involved in platelet aggregation needed for coagulation (1pp40-41). COX-2 mediates inflammation and prostaglandin production. Because the antypyretics are not selective in which COX they inhibit, they damage the gastric mucosa, acetaminophen is toxic to the kidneys, and aspirin diminishes platelet function (1pp40-41). Children should also avoid use of aspirin because of it is associated with Reyes syndrome (1p59).
1. Nowak TJ, Hanfod AG. Pathophysiology: Concepts and applications for health care professionals, 3rd ed. 2004. New York, McGraw-Hill, pp58-60.