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A new study hammers home a message experts have been trying to send to physicians and patients for years: when someone has the wheezing, breathlessness and sputum-producing cough that are the hallmarks of acute bronchitis, taking an antibiotic won't do any good.
Final proof
The new study was necessary, says Dr Arthur Evans, co-director of the Cook County Hospital Collaborative Research Unit in Chicago, because 60 percent of people with acute bronchitis are prescribed antibiotics - often at a high cost - despite a long list of previous trials showing no particular benefit.
Evans and his colleagues used the antibiotic azithromycin for their study because "it presented the best-case scenario," he says. "It is powerful, has a broad spectrum, and few side effects. If any antibiotic would work, this would be it."
The study appears in this week's The Lancet.
No difference between antibiotic and placebo
Adults who showed up with acute bronchitis at the hospitals participating in the study were assigned at random to get either azithromycin or vitamin C. The vitamin served the purpose of a placebo, or inactive substance, because "it has been studied carefully for other respiratory conditions such as the common cold and has not been effective, and the doses we used were unlikely to have any effect," Evans says.
All the patients were also given a cough medicine and an aerosol preparation of albuterol, a standard bronchodilator that opens airways. Their condition was checked a week after treatment began. The trial was stopped after 220 people were treated because there were no detectable differences between those who got the antibiotic and those who got vitamin C.
No tests were done to see whether the bronchitis was caused by a bacterial infection or a virus. Most cases of bronchitis are caused by viruses, against which antibiotics are not effective. Not doing a test is standard medical practice, Evans says, because no good test is available.
Another reason for not trying to tell whether the problem is bacterial or viral is that "even when bacteria are involved, antibiotics don't make you feel better any quicker," says Dr William Hueston, head of family medicine at the Medical University of South Carolina, who has done several studies of his own showing the lack of value of antibiotics.
"It's not the bacteria or viruses in there, but the damage that the bacteria and viruses cause that is the problem," Hueston says. "So even if you get them out, it doesn't help relieve the symptoms."
Despite all the evidence, many doctors continue to prescribe antibiotics, he acknowledges. "It stems from a desire to do something even when doing nothing is the right thing," Hueston says.
More research needed
There is still work to be done, Evans says.
"We know that antibiotics don't work," he says. "More studies need to be done finding out what does work. We chose to treat people symptomatically with an effective cough syrup and a bronchodilator. Evidence is still up in the air about bronchodilators. Some people say they work, others say the evidence is not convincing."
Someone with bronchitis can take vitamin C, Hueston says; at least it does no harm. He also concentrates on relieving the symptoms, with bronchodilators and cough syrups. And anyone who smokes should stop, he adds, since smoking adds to the inflammation that makes bronchitis an uncomfortable condition.
Representatives for Pfizer Inc., which makes Zithromax, did not return a phone call. The drug is approved to treat bronchitis in addition to other ailments, like ear infections.
