Aug. 19, 2009 -- Doctors aren't writing prescriptions for certain antibiotics to treat children's respiratory tract infections as much as they used to, a new study shows.

The researchers -- who included Carlos Grijalva, MD, MPH, of Vanderbilt University's medical school -- used national data to see if antibiotic use was still declining, a trend that began in the 1990s.

Grijalva's team was interested because there's been a long-term effort to tighten up on antibiotic use, in order to fight the rise of antibiotic-resistant bacteria.

On one hand, the study shows an 18% drop in antibiotic prescriptions in people with respiratory tract infections.

That includes a 36% drop in the antibiotic prescription rate for respiratory tract infections among U.S. kids younger than 5, mainly because of fewer doctor visits by kids with ear infection and a drop in prescriptions of certain antibiotics, such as penicillin and amoxicillin, to treat children's respiratory tract infections.

But prescription rates shot up for other antibiotics.

For instance, azithromycin's prescription rate for respiratory tract infections among children younger than 5 rose ninefold between 1995-1996 and 2005-2006. Prescription rates for quinolones (another type of antibiotic) also rose for people aged 5 and older. And antibiotic prescriptions for respiratory tract infections weren't down among people aged 50 and older.

The findings among young children are "encouraging," write the researchers, adding that "further efforts to improve antibiotic selection are needed."

By Miranda Hitti
WebMD Health News

The study appears in The Journal of the American Medical Association.