Acute otitis media is an inflammation of the middle ear (the space behind the eardrum), which is often caused by bacteria. Other than colds or coughs, otitis media is the most common illness young children develop, accounting for at least 30 million visits to the doctor each year.

In the treatment of middle ear infections in children, a single oral dose of the antibiotic azithromycin (Zithromax®) appears to be as effective as another commonly used antibiotic given twice a day for ten days.

A multicenter clinical trial that focused on this treatment was presented at the 38th Annual Meeting of the Infectious Diseases Society of America (IDSA). It was found that response to treatment was equivalent whether children received a single dose of azithromycin or a ten-day course of amoxicillin/clavulanate (Augmentin®).

The randomized, double-blind trial was conducted at nine United States medical centers and included 350 children between the ages of six months and 12 years (average age was approximately three years old). Patients were randomized to receive either a single dose of azithromycin (30 mg/kg) or amoxicillin/clavulanate (45 mg/kg), twice a day for ten days.

Previous to this study, the efficacy of a single-dose treatment of acute otitis media had not been established for any oral antibiotic. The unique characteristics of azithromycin make it a good candidate for single-dose therapy, according to the study's lead investigator, Stan L. Block, MD, Arnold Palmer Hospital for Children and Women, Orlando, Florida.

At the end of therapy, 138 out of 160 azithromycin- treated patients responded to treatment (86 percent), as did 142 of 161 children receiving amoxicillin/ clavulanate (88 percent). At the end of one month, the cure rate remained steady at 75 percent in both patient groups, Dr. Block reported.

The investigators stressed that patients (and their parents) would be more likely to adhere to a single-dose treatment for middle ear infections, since patients often do not finish the course of treatment with the more traditional ten days of antibiotics. This can lead to possible treatment failure and to the development of bacteria that are resistant to the particular medication.

Azithromycin was somewhat better tolerated during the study, with 17 percent of patients experiencing treatment-related symptoms, compared with 23 percent receiving amoxicillin/clavulanate. More children discontinued therapy while on amoxicillin/clavulanate (six versus two, respectively), and twice as many experienced diarrhea (22 versus 11, respectively). Vomiting, which was generally mild, occurred in seven children in each group.

Azithromycin is currently given over a period of five days. The Food and Drug Administration (FDA) is currently considering approval of the single-dose therapy.

"The results of this study indicate that a single, oral dose of medication can accomplish what traditionally has taken up to ten days. Families and healthcare providers are likely to appreciate this alternative to conventional treatment," added a co-investigator, Stephen Eppes, MD, Associate Director of Pediatric Infectious Diseases, Alfred I. DuPont Hospital for Children, Wilmington, Delaware. "Likewise, the single-dose administration is likely to encourage improved patient compliance so that children are treated successfully the first time, reducing the risk of developing resistance to the antibiotic."