NICE, FRANCE — Family physicians prescribe penicillins most often, whereas surgeons prescribe fluoroquinolones more frequently than any other specialty.
These are some of the findings from a 3-year study examining prescribing patterns of oral antibiotics by physician specialty in the United States. This is the first study to offer a national perspective on outpatient antimicrobial prescribing by physician specialty, Katie J. Suda, Pharm. D., and her associates reported at the 16th European Congress of Clinical Microbiology and Infectious Diseases.
“Over the 3 years, prescribing patterns did vary significantly by physician specialty,” she said.
Investigators evaluated outpatient antibiotic prescriptions dispensed in 2001–2003 from nine managed health care plans. Medications were stratified into classes and formulations as defined by the American Hospital Formulary Service. Diagnostic codes were defined according to Medicode (now Ingenix).
A total of 7,613 physicians wrote 48,182 antibiotic prescriptions for 26,875 patients. The average patient age was 34 years.
The majority of patients were diagnosed with upper respiratory tract infection followed by sinusitis and genitourinary infections.
Physician specialties included family practice (42%), internal medicine (14%), pediatrics (21%), emergency medicine (5%), specialists (5%), dermatologists (4%), obstetricians/gynecologists (3%), surgeons (3%), and others such as pathologists and psychiatrists (3%).
Overall, penicillins were dispensed most frequently, followed by macrolides, cephalosporins, and fluoroquinolones, said Dr. Suda, of the University of Tennessee Health Science Center in Memphis.
Dermatologists most often prescribed tetracyclines (75%); emergency medicine physicians, macrolides (42%); ob.gyns, nitrofurans (27%); pediatricians, penicillins (38%); and surgeons, fluoroquinolones (25%). Family physicians prescribed penicillins most often, while internists prescribed fluoroquinolones.
All physician groups prescribed β-lactamase inhibitors more frequently than any other agent for the treatment of skin and skin structure infections.
Internists prescribed broader-spectrum agents for the treatment of urinary tract infections, whereas ob.gyns. prescribed narrower-spectrum agents, even though not all of their patients may be pregnant or lactating, she said.
Fluoroquinolones were used most often for UTIs by family physicians, internists, and emergency physicians, and nitrofurans by ob.gyns. and surgeons.
Beta-lactamase inhibitors were the treatment of choice for upper respiratory tract infections for family practitioners and specialists.
But internists and emergency physicians were more likely to prescribe macrolides, which may be because these physicians see more patients with complicated conditions, she said.
Pediatricians used penicillins most often, followed by macrolides and beta-lactamase inhibitors.
Overall, lower respiratory tract infections were treated most often with macrolides, followed by fluoroquinolones.
Audience members questioned whether the findings were representative of family care in the United States, particularly in light of the high fluoroquinolone use that was reported.
Dr. Suda said she believed the findings were representative of a managed care population under the age of 65 years, but added that she was unable to validate the findings against data from other plans because most organizations won't release the information.
The most commonly prescribed fluoroquinolones were levofloxacin (more than 50%), followed by ciprofloxacin, moxifloxacin, and gatifloxacin, she said.