Background: The reported prevalence of nonprescription antibiotic use in the United States varies from 5% among socioeconomically and ethnically diverse primary care patients to 66% among Latino migrant workers. Reports indicate that people obtain and take antibiotics from stores or flea markets in the United States, friends or relatives, and leftover antibiotics from previous prescriptions. This unsafe practice may lead to unnecessary and inappropriate antibiotic use and increases the risk of antibiotic resistance. As groundwork to develop an intervention to decrease nonprescription antibiotic use, we mapped reported drivers of nonprescription use to the Kilbourne conceptual framework for advancing health disparities research. Methods: The Kilbourne framework consists of 3 phases: (1) detection of health disparities and identification of vulnerable populations, (2) understanding why disparities exist, and (3) reducing or eliminating disparities through interventions. We focused on the first 2 phases and mapped the identified drivers of nonprescription antibiotic use onto the key domains of the Kilbourne conceptual framework: patient, healthcare system, and clinical encounter factors. We also conducted brief field research to explore anecdotal reports regarding availability of nonprescription antibiotics in our community. Results: We found 8 studies addressing factors related to nonprescription antibiotic use in the United States. These studies were primarily qualitative and included Spanish-speaking Hispanic and Latino immigrants. Figure 1 shows the proposed factors that may directly or indirectly predict nonprescription antibiotic use. Key potential factors are individual factors, psychosocial factors, resources, healthcare system factors, and clinical-encounter factors. For example, patients with inadequate health literacy may have poor access to care because of difficulty finding providers and choosing or navigating insurance plans; thus, they may be at risk for nonprescription use. At the same time, patients with inadequate health literacy may be at risk for using nonprescription antibiotics for a viral infection because of difficulty understanding medication labels or package inserts. The relevance of resources (availability) to nonprescription antibiotic use was supported by our research team’s purchase of amoxicillin, tetracycline, and metronidazole without prescriptions from a flea market in Houston, Texas. Conclusions: The Kilbourne conceptual framework provides a strong, comprehensive basis for research and intervention in the challenging problem of nonprescription antibiotic use. Ongoing research will test the proposed relationships between patient, healthcare system, and clinical-encounter factors and nonprescription antibiotic use outcomes. We are conducting a survey among both indigent and insured patient populations to identify the relative importance of these factors and to validate our proposed conceptual framework of nonprescription antibiotic use.
Funding: This project was supported by grant number R01HS026901 from the Agency.