A survey of patient practices regarding leftover antibiotics reveals a potential source of antibiotic overuse.

Taking leftover prescribed antibiotics without consulting a healthcare professional is problematic for the efficacy, safety, and antibiotic stewardship. We conducted a cross-sectional survey of adult patients in English and Spanish between January 2020 and June 2021 in six safety-net primary care clinics and two private emergency departments. We assessed the reasons for stopping prescribed antibiotics early and what was done with the leftover antibiotics. Additionally, we determined 1) prior leftover antibiotic use, 2) intention for future use of leftover antibiotics, and 3) sociodemographic factors. Of 564 survey respondents (median age of 51), 45% (251/564) reported a history of stopping antibiotics early, with 171/409 (42%) from safety net and 80/155 (52%) from the private clinics. The most common reason for stopping prescribed antibiotics early was "because you felt better" (194/251, 77%). Among survey participants, prior use of leftover antibiotics was reported by 149/564 (26%) and intention for future use of leftover antibiotics was reported by 284/564 (51%). In addition, higher education was associated with a higher likelihood of prior leftover use. Intention for future use of leftover antibiotics was more likely for those with transportation or language barriers to medical care and less likely for respondents with private insurance. Stopping prescribed antibiotics early was mostly ascribed to feeling better, and saving remaining antibiotics for future use was commonly reported. To curb nonprescription antibiotic use, all facets of the leftover antibiotic use continuum, from overprescribing to hoarding, need to be addressed.