High-Dose vs Standard-Dose Amoxicillin Plus Clavulanate for Adults With Acute Sinusitis: A Randomized Clinical Trial.

Importance: Acute bacterial sinusitis is common, but currently recommended antibiotic treatment provides minimal benefit. Objective: To confirm the previous finding that high-dose amoxicillin plus clavulanate (with double the amount of amoxicillin) may be superior to standard-dose amoxicillin plus clavulanate in adults. Design, Setting, and Participants: This double-blind, comparative-effectiveness randomized clinical trial was conducted from February 26, 2018, through May 10, 2020, at the academic primary care internal medicine and pediatrics practice of Albany Medical Center, located in Cohoes, New York. Participants included adults aged 18 years or older who were prescribed amoxicillin plus clavulanate for acute bacterial sinusitis diagnosed in accordance with the Infectious Diseases Society of America guidelines. Interventions: Amoxicillin 875 mg with clavulanate 125 mg plus either placebo (standard dose) or amoxicillin 875 mg (high dose) twice a day for 7 days. Main Outcomes and Measures: The primary efficacy outcome was a global rating of "a lot better" or "no symptoms" at the end of 3 days of treatment using a Global Rating of Improvement scale, with outcomes ranging from 1 (a lot worse) to 6 (no symptoms). The primary adverse effect outcome was severe diarrhea at 3 or 10 days after the start of treatment. Results: At an unplanned interim analysis prompted by COVID-19 restrictions, 157 of a projected 240 participants had been enrolled (mean age, 48.5 [range, 18.7-84.0] years; 117 women [74.5%]), with 79 randomized to the standard dose and 78 to the high dose; 9 and 12, respectively, withdrew or were lost to follow-up before the assessment of the primary outcome. At day 3, 31 of 70 participants (44.3%) in the standard-dose group reported a global rating of "a lot better" or "no symptoms," as did 24 of 66 (36.4%) in the high-dose group, for a difference of -7.9% (95% CI, -24.4% to 8.5%; P = .35). The study was, therefore, stopped for futility. Diarrhea was common in both groups by day 3, with any diarrhea reported in 29 of 71 participants (40.8%) receiving the standard dose and 28 of 65 (43.1%) receiving the high dose and severe diarrhea reported in 5 of 71 (7.0%) and 5 of 65 (7.7%), respectively. Conclusions and Relevance: The results of this randomized clinical trial suggest that adults treated for clinically diagnosed acute sinusitis did not appear to benefit from taking high-dose compared with standard-dose amoxicillin plus clavulanate. Trial Registration: ClinicalTrials.gov Identifier: NCT03431337.

High-dose versus standard-dose amoxicillin/clavulanate for clinically-diagnosed acute bacterial sinusitis: A randomized clinical trial.

BACKGROUND: The recommended treatment for acute bacterial sinusitis in adults, amoxicillin with clavulanate, provides only modest benefit. OBJECTIVE: To see if a higher dose of amoxicillin will lead to more rapid improvement. DESIGN, SETTING, AND PARTICIPANTS: Double-blind randomized trial in which, from November 2014 through February 2017, we enrolled 315 adult outpatients diagnosed with acute sinusitis in accordance with Infectious Disease Society of America guidelines. INTERVENTIONS: Standard-dose (SD) immediate-release (IR) amoxicillin/clavulanate 875 /125 mg (n = 159) vs. high-dose (HD) (n = 156). The original HD formulation, 2000 mg of extended-release (ER) amoxicillin with 125 mg of IR clavulanate twice a day, became unavailable half way through the study. The IRB then approved a revised protocol after patient 180 to provide 1750 mg of IR amoxicillin twice a day in the HD formulation and to compare Time Period 1 (ER) with Time Period 2 (IR). MAIN MEASURE: The primary outcome was the percentage in each group reporting a major improvement-defined as a global assessment of sinusitis symptoms as "a lot better" or "no symptoms"-after 3 days of treatment. KEY RESULTS: Major improvement after 3 days was reported during Period 1 by 38.8% of ER HD versus 37.9% of SD patients (P = 0.91) and during Period 2 by 52.4% of IR HD versus 34.4% of SD patients, an effect size of 18% (95% CI 0.75 to 35%, P = 0.04). No significant differences in efficacy were seen at Day 10. The major side effect, severe diarrhea at Day 3, was reported during Period 1 by 7.4% of HD and 5.7% of SD patients (P = 0.66) and during Period 2 by 15.8% of HD and 4.8% of SD patients (P = 0.048). CONCLUSIONS: Adults with clinically diagnosed acute bacterial sinusitis were more likely to improve rapidly when treated with IR HD than with SD but not when treated with ER HD. They were also more likely to suffer severe diarrhea. Further study is needed to confirm these findings. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02340000.