Do Fever-Reducing Drugs Prolong Illness?

We've all heard the old saw: "Take two aspirin and call me in the morning."

Primary-care doctors such as Israel Alvarez still dispense that advice when their patients fall victim to the flu. Aspirin is what pharmacists call an "antipyretic," a class of drugs including acetaminophen, ibuprofin and naproxen sodium, that have the ability to lower fever.

"Since we know that flu runs its own course, we just treat it symptomatically," said Alvarez, chief of primary-care services at the Veterans Affairs Medical Center in Riviera Beach. "That means we use an antipyretic to make people feel better."

But a newly published study from the journal Pharmacotherapy suggests that drugs with the power to lower fever also may come with a price -- a longer illness.

Researchers at the University of Maryland-Baltimore schools of Pharmacy and Medicine looked at data from 54 volunteers who had been infected with Influenza A virus. They found that the 13 volunteers who took aspirin or Tylenol suffered flu symptoms for an average of 3.5 days longer than those who went untreated.

Dr. Philip A. Mackowiak, the vice chairman of the University of Maryland's medical school, said the data was from vaccine studies done in 1978 and 1987. He said the results show that new studies are needed.

"We're not recommending that people stop taking aspirin or Tylenol when they have flulike symptoms," Mackowiak said. "But one needs to consider the possibility that while one may feel better, the price one pays may be that the illness is prolonged."

The manufacturer of Tylenol, the brand name of acetaminophen, said the study was too small to be valid, and based on 20-year-old data from an unrelated study -- one designed to investigate vaccinations, not the length of flu symptoms.

Chances are that the sickest patients were the ones given the fever-reducing drugs, said Mark Gutsche, a spokesman for McNeil Consumer Health Care.

"The sicker patient probably is more likely to take antipyretics. The sicker you are, the more medications you take," Gutsche said. "It's like saying, orange juice must cause colds because people who have the worst colds usually drink a lot of orange juice."

The study looked at volunteers exposed to three diseases, one viral, Influenza A, and two types of bacterial pathogens, Rocky Mountain spotted fever and Shigellosis. The anti-fever therapies were not associated with a prolonged illness for the two bacterial diseases.

But Mackowiak said investigators found that volunteers with Influenza A who were given aspirin or acetaminophen suffered flu symptoms for an average of 8.8 days. Those whose illness went untreated by fever-reducing drugs suffered for an average of 5.3 days.

Mackowiak said the data support a growing body of evidence that fever-reducing drugs can prolong the time to recover for some viral diseases. A 1989 study found that children with chicken pox who were given acetaminophen, or Tylenol, required more time for their sores to heal. A 1990 study found that volunteers exposed to the cold virus had a weaker immune response when they were treated with aspirin or acetaminophen.