Streptococcal pharyngitis, sinusitis, acute otitis media (AOM), community-acquired pneumonia (CAP), skin and soft tissues infection (SSTI), and acute cystitis rank among the most common bacterial infections in the United States that lead to outpatient antibiotic prescriptions. When antibiotics are indicated for these conditions, the recommended duration of therapy varies by infection type. “Using the minimum effective antibiotic therapy duration can help minimize the risk for adverse events and antibiotic resistance,” says Sharon Tsay, MD.

For a study published in Clinical Infectious Diseases, investigators described the duration of common infections treated in doctors’ offices—including pharyngitis, sinusitis, AOM, CAP, SSTI, and acute cystitis—to identify opportunities for improving prescribing practices. Using the 2017 National Disease and Therapeutic Index dataset, 2,889 sampled antibiotic prescriptions were examined, translating to nearly 31.5 million national prescriptions from private practice, office-based physicians in various specialties. Of these, 11% were azithromycin, which has different duration recommendations based on its pharmacokinetics; therefore these prescriptions were excluded from duration analyses, leaving about 28 million antibiotic prescriptions assessed in the study.

Defaulting to 10-Day Antibiotic Courses

The median duration of antibiotic use was 10 days for every condition except acute cystitis, for which the median duration was 7 days (Table). “We found that clinicians defaulted to 10-day courses for most conditions, regardless of guideline recommendations,” says Dr. Tsay. “For some conditions and age groups, such as pharyngitis, pediatric sinusitis, and pediatric AOM, 10 days of antibiotic therapy aligns with guidelines. However, for many conditions—specifically sinusitis, CAP in adults, and cellulitis—10 days of therapy is likely excessive for most patients based on guideline recommendations.”

Overall, 55% of antibiotic courses exceeded the guideline-recommended minimum of effective durations. This translated to approximately 54.5 million potentially excessive days of antibiotic therapy. Among adults, 74% of antibiotic courses exceeded the minimum guideline-recommended duration, compared with a 36% rate in children.

Antibiotic Course Pros & Cons

The study identified several positive trends in the prescription of antibiotics according to guideline recommendations for duration of therapy. For example, 85% of the estimated antibiotic prescriptions in adults with pharyngitis and 97% in children with pharyngitis were for 10 days, which is the guideline-recommended duration. For cellulitis, 99% of antibiotic prescriptions for adults and 93% for children were made for longer than 5 days, which is recommended, and the majority of these prescriptions were for 10 days. For abscesses, 88% of prescriptions in adults and 80% in children were for guideline-recommended 5- to 10-day durations.

However, the study also found that 90% of antibiotic prescriptions for sinusitis in adults exceeded the guideline-recommended duration of 5-7 days. For AOM, courses of 5-7 days or 7 days are suggested for select children aged 2 or older, but only 5% of prescriptions for this population were for 5-7 days. Just 6% of prescriptions for CAP in adults were for 5 days, which is the appropriate duration for most patients, according to guidelines. After accounting for varying antibiotic agents used for acute cystitis in females aged 12-64, at least 75% of these prescriptions had durations longer than what is recommended by guidelines.

Confidence in Shortening Antibiotic Courses

“The body of evidence on minimum effective antibiotic therapy duration has grown and, consequently, guidelines recommend shorter antibiotic courses for many conditions,” Dr. Tsay says. “For example, shorter courses of antibiotics are recommended for conditions like sinusitis, CAP in adults, and acute cystitis in women. Increased awareness of guideline recommendations for the duration of antibiotics for common conditions can improve patient safety and outcomes.”

Further research is needed to improve the treatment of infections and optimize the duration of antibiotic therapy, according to Dr. Tsay. “Studies that focus on implementing interventions to improve concordance with guideline recommendations, such as providing clinical decision support to clinicians, are needed,” she says. “Likewise, the development of stronger evidence and guidelines for common infections could give clinicians more confidence in shortening antibiotic prescription courses.”