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Trial shows azithromycin is no better than vitamin C for bronchitis

Roger Dobson, Abergavenny

An antibiotic commonly prescribed for acute bronchitis is no better than low doses of vitamin C, according to new research.

A double blind, randomised controlled trial has concluded that azithromycin is ineffective and should not be prescribed for acute bronchitis.

A report of the research (Lancet 2002;359:1648-54)[CrossRef][ISI][Medline] says that every year in the United States some 10 million adults seek treatment for acute bronchitis and that most of them are given antibiotics, although the pathogens involved are viruses in most cases.

"Many experts condemn such treatment, citing three main reasons: weak or conflicting experimental evidence of clinical benefit; lack of a strong biological rationale; and increasing societal concerns about widespread antibiotic resistance," says the report.

The researchers, from Cook County Hospital, Chicago, and elsewhere, set out to compare the benefits of azithromycin with the benefits achieved with capsules of vitamin C.

"We chose vitamin C instead of a traditional placebo because the results of several focus groups we undertook showed that people would probably refuse to take part in any randomised trial of acute bronchitis if the placebo group received a sugar pill. They suggested that a randomised trial of antibiotics and a multivitamin or some other vitamin pill would be acceptable," say the researchers.

Around 200 patients with acute bronchitis but without evidence of underlying lung disease took part in the trial. Measures used to compare the effects of the two treatments included time taken to return to work or usual activities and improvements in health related quality of life.

"These results show that azithromycin is no more effective than low-dose vitamin C for treatment of acute bronchitis. Given the lack of evidence that low-dose vitamin C is beneficial, we conclude that azithromycin is ineffective and should not be prescribed for patients with acute bronchitis," says the report.

Researchers recommend that azithromycin, which is marketed as Zithromax in the United Kingdom, should not be prescribed for acute bronchitis