In this season of sniffles, sneezes, coughs and fever, millions of Americans reach into their medicine cabinets for aspirin, acetaminophen or ibuprofen. These drugs bring down an elevated temperature, but is that a good idea?
Even though most cold and flu remedies contain fever reducers, there is little evidence that they speed healing. Such products may even be counterproductive.
Why do we get a fever when we get sick? Biologists have discovered that an elevated temperature helps mobilize immune-system defenses. Fever also makes it harder for viruses and other microorganisms to reproduce (Journal of Virology, February 1982).
Humans are not the only creatures who spike a fever when they are infected. Other mammals do, too. Even cold-blooded vertebrates such as lizards will crawl to a sunny rock to raise their body temperatures – and if they are prevented, they are more likely to succumb to a serious infection (Science, April 11, 1975).
Research suggests that people who develop moderate fevers are more likely to survive serious infections (Australian Critical Care online, Dec. 3, 2012). So what happens when we lower a fever with drugs?
More than a quarter-century ago, scientists reported that treating a cold with aspirin increased virus shedding (Journal of the American Medical Association, March 24, 1975). That means people are more likely to suffer symptoms and spread their illness to others.
An experiment in which volunteers were infected with cold virus and treated with aspirin, acetaminophen, ibuprofen or placebo showed that the medications reduced the immune response to the infection, increased nasal symptoms and seemed to prolong virus shedding (Journal of Infectious Disease, December 1990). In a different experiment, volunteers infected with influenza A virus were sick three to four days longer if they received aspirin or acetaminophen (Pharmacotherapy, December 2000).
It probably comes as a surprise to most health care professionals to learn that there are no double-blind placebo-controlled clinical trials measuring the benefits of lowering a fever when patients have influenza (Journal of the Royal Society of Medicine, October 2010). As a result, the conventional advice to rest in bed, drink plenty of fluids and take aspirin or acetaminophen for the flu is not evidence-based.
If drug companies want to promote cold and flu remedies that contain fever reducers, they should conduct placebo-controlled trials to prove their products do more good than harm.
So what should people do if they have sniffles and a moderate fever? A century ago, grandmothers had a different way of dealing with flu-like symptoms. They frequently rubbed the chest with a menthol and camphor ointment (think Vicks VapoRub) or a mustard plaster. Then they piled on the quilts to “sweat out the fever” and administered a good dose of hot, homemade chicken soup.
Such old-fashioned home remedies may not have had any evidence either, but current science suggests that they may have been more helpful than today’s drugstore remedies. Encouraging the body’s natural immune response rather than fighting it might have helped people recover faster.