By Robert Preidt
THURSDAY, Aug. 8 (HealthDay News) -- When prescribing antibiotics, American doctors choose the most powerful drugs more than 60 percent of the time, a new study finds.
But more than 25 percent of the prescriptions for these "broad-spectrum" antibiotics -- which are capable of killing multiple types of bacteria -- are useless because the infection is caused by a virus, which cannot be treated with antibiotics, the researchers said.
The investigators analyzed data from more than 238,000 ambulatory visits made by patients 18 and older to doctors, outpatient clinics and emergency rooms in the United States between 2007 and 2009. They found that broad-spectrum drugs accounted for 61 percent of antibiotic prescriptions, while narrow-spectrum drugs accounted for the other 39 percent.
Based on that sample, the researchers estimated that antibiotics were prescribed in about 101 million visits nationwide each year during the study period, including 62 million in which broad-spectrum antibiotics were prescribed and 39 million in which narrow-spectrum antibiotics were prescribed.
The study was published July 29 in the Journal of Antimicrobial Chemotherapy.
Although this study focused on adult ambulatory care visits, the prescription pattern for children is similar, said study senior author Dr. Adam Hersh, an infectious-disease expert and assistant professor of pediatrics at the University of Utah School of Medicine.
"Many antibiotics prescribed for children are unnecessary, particularly for conditions caused by viruses, where antibiotics don't help at all," he said in a university news release. "Even when an antibiotic is indicated, such as for strep throat or some ear infection, physicians often prescribe an antibiotic such as a Z-Pak, which can be less effective than amoxicillin."
Antibiotic overuse among children and adults is a serious problem and a threat to everyone's health, said study co-author Dr. Lauri Hicks, a medical epidemiologist at the U.S. Centers for Disease Control and Prevention and the University of California, San Francisco.
"The biggest problem with using antibiotics when they're not needed is the development of antibiotic resistance, which is when bacteria survive by outsmarting the antibiotic," she said in the news release. "Common infections become difficult to treat, and when you really need an antibiotic, it may not work."
Hersh urged patients to play a role by asking their doctor if they really need the antibiotic and whether the antibiotic is the best choice for their infection.