LONDON (AP) _ An antibiotic commonly given for acute bronchitis is no better than low-dose vitamin C at treating the coughing attacks, a new study has found.
Millions of people visit doctors every year for acute bronchitis and most receive antibiotics _ even though there's not much evidence antibiotics help, and it seems the condition is most often caused by a virus, not bacteria.
The study, published this week in The Lancet medical journal, concluded that doctors should stop giving the antibiotic azithromycin, known by the brand name Zithromax, to patients with acute bronchitis.
Some experts said the findings confirm that antibiotics in general are useless for acute bronchitis and that no antibiotic, whatever the type, should be given for the condition.
Zithromax is not the only antibiotic experts have doubts about when it comes to treating acute bronchitis.
A recent analysis of studies involving a variety of other antibiotics concluded that while it's possible they might sometimes clear up the cough about a day early, there's a hefty price to pay in side effects.
``It was a maybe, but this study pretty well refutes that,'' said Dr. Lorne Becker, head of family medicine at the State University of New York Upstate Medical University in Syracuse, who was not involved with the latest research but heads an expert group that regularly analyzes the research on antibiotics and bronchitis.
Becker said he found the evidence definitive.
``There may be, hidden in this big group of people who don't benefit, a small group of people who do, but I don't think there's going to be a flip-flop on this for the general person coming in with bronchitis,'' he said.
Zithromax, made by Pfizer, is used to treat many bacterial infections in different parts of the body, most commonly for pneumonia and sexually transmitted chlamydia infections. Pfizer stressed that its drug targets only bacteria and its approval for use in bronchitis is based on the assumption that sometimes the coughing is caused by one of several bacteria types known to be killed by the drug.
Part of the problem is that it is not easy to tell whether someone's bronchitis is caused by a virus or bacteria. There is no test. Experts are not even sure whether bronchitis is ever caused by bacteria, and there is no evidence that antibiotics prevent bronchitis patients from developing a more serious pneumonia infection.
However, many patients expect their doctors to ``do something'' about it, so they are most often sent away with a course of antibiotics.
Experts have condemned such inappropriate use of antibiotics because it allows germs to build up immunity to the drugs, which then become useless when they are really needed.
The study by researchers at Cook County Hospital and Rush Medical College in Chicago involved 220 adults diagnosed with acute bronchitis _ a persistent cough.
Half the patients were given Zithromax for five days and the others were given low-dose vitamin C pills. Vitamin C has not been shown to be any good for bronchitis and the patients didn't know which drug they were getting, so the pills were considered a placebo.
On day seven, the scientists measured how much improvement each patient had seen in the health-related quality of their lives. The proportion of patients who had returned to their normal daily activities by day seven was the same in both groups _ 89 percent.