Evidence-Based Sinusitis

Antibiotic Choices

Once a doctor and patient have decided to use antibiotics, the two sets of guidelines differ on which drug should be first-line treatment. The AAO-HNS guidelines call for amoxicillin (unless there’s a penicillin allergy), because it’s cheaper and carries a lower risk of side effects than other antibiotics. IDSA recommends amoxicillin and clavulanic acid (Augmentin), based on the latest microbiology evidence. The AAO-HNS was stricter in relying on clinical trial data, whereas the IDSA also incorporated microbiology trends.

“The microbiology has changed, resistance patterns have changed, and because of the pneumococcal vaccine, the types of pathogens associated with sinusitis have changed,” Dr. Chow said. Specifically, there’s more Haemophilus influenzae and less Streptococcus pneumoniae, particularly in children. And, Dr. Chow added, “with H. influenzae, the bacteria can break down amoxicillin, so we recommend amoxicillin plus clavulanate.”

The IDSA guidelines take an in-depth look at second-line and alternative antibiotic choices in children and adults. The AAO-HNS guidelines don’t go beyond the first-line treatment drug.

Peter Hwang, MD, professor and director of the Stanford Sinus Center at Stanford University School of Medicine in Stanford, Calif., said he has no problem with the IDSA’s broader interpretation of the data. In fact, he tends to choose amoxicillin-clavulanate in his practice based on knowledge of the local bacterial resistance patterns. At Stanford, a majority of H. influenzae types are beta lactamase producing, and almost all Moraxella catarrhalis are beta lactamase positive, he said. “As clinicians, we’re choosing antibiotics based on the antibiogram for our community or our hospital,” he said.

Drs. Merenstein and Rosenfeld argued for the conservative approach. Augmentin has never outperformed amoxicillin in a clinical trial; therefore, evidence-based guidelines cannot recommend its use as a first-line treatment, absent other considerations for an individual case. “The amoxicillin-clavulanate opinion is not based on trials; it’s just theoretical,” said Dr. Merenstein.

Treatment Failure

The AAO-HNS guidelines say to consider another therapy if symptoms haven’t improved after seven days of treatment. The IDSA says to look sooner than that if there’s no improvement after three to five days of antibiotics. (Both advise reassessment with worsening symptoms.)

Again, Dr. Rosenfeld cited clinical trial data for the AAO-HNS recommendation. “After the first few days, maybe 20 to 30 percent of patients will be better, but it took seven days before seeing many people improve,” he said.

Dr. Chow cited clinical observations of when patients get better. “If they’re not going to respond, we’ll know in three to five days,” he said. Indeed, the guidelines cite pediatric data in which 45 percent of patients were cured within three days, and ‘many others’ had improved.