Atlanta—When discussing the appropriateness of antibiotic therapy for sinusitis, the most common condition for which outpatient antibiotic therapy is prescribed in the United States, the focus usually is on whether to prescribe the drugs and, if so, which one to choose.

A new study in JAMA Internal Medicine has raised another question, however: Why are prescriptions written for so many more days than recommended in clinical guidelines?

Researchers from the CDC point out that, when antibiotics are deemed necessary for the treatment of acute bacterial sinusitis, the Infectious Diseases Society of America evidence-based clinical practice guidelines recommend 5 to 7 days of therapy for patients with a low risk of antibiotic resistance who have a favorable response to initial therapy.

Yet, study results indicate that 69.6% of antibiotic prescriptions were written for 10 days or longer; the percentage soared to 91.5% when azithromycin was excluded.

To reach those conclusions, the study team analyzed nearly 3.7 million visits by adults in which physicians prescribed antibiotics for acute sinusitis. The data were obtained from a 2016 national index that is a sample of drug therapies prescribed by private- practice physicians

Antibiotics were grouped as penicillins, tetracyclines, fluoroquinolones, cephalosporins, azithromycin, or other. The researchers also described treatment duration in days for all antibiotic prescriptions, as well as those excluding azithromycin, and by drug group.

“Notably, no penicillin or tetracycline prescriptions were for 5-day courses, and only 5% of antibiotic prescriptions were for 7-day courses of penicillins, tetracyclines, or fluoroquinolones,” the study authors note. “Although 7- to 10-day courses are recommended for patients at high risk or who have experienced failure of initial treatment, it is unlikely that such cases represent most patients in our study. Earlier work has shown that 90% of patients with sinusitis that is treated with antibiotics do not require additional antibiotic therapy.”

The study points to past research indicating that shorter courses of antibiotics, 3 to 7 days, have been shown to produce similar outcomes with fewer adverse drug reactions, compared to longer durations of 6 to 10 days.

Also of concern to the researchers was that more than 20% of prescriptions were for a 5-day course of azithromycin. IDSA specifically recommends against the use of azithromycin for the treatment of sinusitis, because of its strong link to the development of drug resistance.

“In addition, because of high and persistent concentrations of azithromycin in tissue, 5 days of azithromycin therapy approximates 10 days of erythromycin therapy; therefore, a shorter course of treatment with azithromycin does not involve a shorter duration of antibiotic exposure,” study authors explain.

“Outpatient antibiotic stewardship programs can optimize infection management by ensuring guideline-concordant treatment, including the use of minimum effective durations of antibiotic therapy,” the report concludes. “The durations of most courses of antibiotic therapy for adult outpatients with sinusitis exceed guideline recommendations, which represents an opportunity to reduce the unnecessary use of antibiotics when therapy with antibiotics is indicated.”

 « Click here to return to Weekly News Update.