Use of Antibiotics Without a Prescription in the U.S. Population

When people use antibiotics without a prescription, they often take unnecessary medication or choose an inappropriate drug or dose. Avoidable adverse events and increased risk for inducing antibiotic resistance among colonizing or infecting bacteria may result (1). Nonprescription use includes obtaining and taking antibiotics without a prescription, taking another person's antibiotics, or taking one's own stored antibiotics for an indication other than that for which they were originally prescribed. Unlike most drugs that affect only an individual patient if used incorrectly, misuse of antibiotics can harm others by increasing within-household and even global risk for antimicrobial resistance and secondary contagious sequelae, such as Clostridioides difficile infection (1). Antimicrobial resistance is increasingly recognized as a major threat to global human health (2). Treatment costs for antibiotic-resistant infections have doubled since 2002 and now exceed $2 billion annually (3). At the individual level, important safety issues related to nonprescription antibiotic use include adverse drug reactions, drug interactions, masking underlying infectious processes, superinfection, and disruption of the healthy microbiome. For example, in nationally representative surveillance data, antimicrobials accounted for 19% of all visits to emergency departments for adverse events in the United States (4). Although many research initiatives in the United States have focused on reducing inappropriate antibiotic prescribing by health care providers, little work has addressed overuse of antibiotics and nonprescription use by patients outside the providerpatient relationship (5). To design and deploy interventions to reduce nonprescription antibiotic use, we must first understand its prevalence; characteristics of patients most likely to use antibiotics without a prescription; types of symptoms that trigger nonprescription use; and the provider, organizational, and health system factors driving it. In this scoping review, we systematically mapped research on nonprescription antibiotic use in the United States and identified gaps in knowledge. We sought to answer 2 questions: What are the prevalence, sources, and characteristics of nonprescription antibiotic use in the U.S. population, and what are the factors influencing it? Methods We performed a scoping review because we had a broad purpose, anticipated heterogeneous studies, and intended to identify knowledge gaps. We followed the PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) guidelines (6) and the scoping review methods manual developed by the Joanna Briggs Institute (7). We did not develop a formal protocol. Data Sources and Searches We searched PubMed, CINAHL, Scopus, and EMBASE without language restrictions from 1 January 2000 to 31 March 2019. We used the PRESS (Peer Review of Electronic Search Strategies) checklist to develop the search strategy (8). Search terms and the PubMed search strategy were peer-reviewed by an experienced librarian and are presented in the Appendix. EMBASE and Scopus searches included gray literature. We used EndNote to remove internal (within a database) and external (between databases) duplicates. We also reviewed the bibliographies of retrieved articles and performed a Google search on 31 March 2019 to identify gray literature. Study Selection We used the PCC (Population, Concept, and Context) framework to define eligibility criteria (6). Any type of document (for example, a journal article, letter, or editorial) from a peer-reviewed publication that described nonprescription antibiotic use in a U.S. population was eligible for inclusion. We included documents that reported at least 1 of the following: use of antibiotics obtained without a prescription, use of stored antibiotics for an indication other than that for which they were originally prescribed, storage of antibiotics for possible future use, intention to use antibiotics without medical guidance, or factors influencing nonprescription antibiotic use. No limitations were imposed with regard to study design or language. Two independent reviewers (L.G. and G.G.) screened titles and abstracts for relevance, without blinding to journal or authors, and then the full texts of all publications deemed potentially relevant. Disagreements on study selection and extraction were resolved by consensus with a third reviewer (B.W.T.). Data Extraction Three reviewers (L.G., G.G., and B.W.T.) jointly developed a data charting form that was piloted on 3 articles. Two reviewers (L.G. and G.G.) then independently charted data, discussed results, and updated the data charting form in an iterative process. Modifications included adding new outcomes of interest and population subgroups (such as injection drug users). Variables extracted for data charting included authors, year of publication, study design, focus of the article, sample size, population characteristics, and key outcomes and results. We did not critically appraise studies or confirm abstracted data with study investigators. Data Synthesis We grouped and summarized study data by population setting because we deemed the health care needs and challenges of some populations (for example, injection drug users) to be distinct from those of others (for example, the general population). We focused on 2 key themes based on the research questions of the study: prevalence of nonprescription antibiotic use, and factors driving it. Role of the Funding Source This work was not funded. Results Of 17422 retrieved articles, 31 met inclusion criteria (Figure 1). Summary characteristics of studies are presented in Appendix Tables 1 and 2. Figure 1. Study selection. Appendix Table 1. Descriptive Summary of Studies Performed in the General Population, From Oldest to Most Recent Appendix Table 2. Descriptive Summary of Studies Performed in Injection Drug Users Study Populations and Settings Four populations were studied: patients or parents of patients outside health care settings (916), patients or parents of patients within health care settings (1720), Hispanic/Latino populations (2124), and injection drug users (2528). Three of the 8 studies performed in the general population (for example, people outside a health care setting) used a random-digit dialing telephone survey (10, 11, 14). Other general population studies surveyed patients or their parents waiting for care in emergency departments or primary care clinics (1720). One study enrolled patients from a sexually transmitted infection (STI) clinic and a county jail (29). Focus and Outcomes Several studies focused on the availability of antibiotics without a prescription from flea markets, pet stores, botanical or health food stores, or online (21, 24, 3035). Others explored nonprescription use from a range of sources, including leftover prescribed courses, markets or stores, family or friends, and antibiotics obtained without a prescription from other countries (9, 11, 15, 16, 1820, 36). In 1 study, patients in an STI clinic and a county jail were interviewed about self-treatment with antibiotics (29). All studies of injection drug users examined self-treatment of abscesses and injection-related wounds with antibiotics obtained on the street (2528, 37, 38). Five studies explored factors influencing nonprescription use in Hispanic/Latino populations (22, 24, 31, 33, 39). There was substantial heterogeneity of outcome measurement across studies. Survey questions relating to use of antibiotics without a prescription used different time frames, ranging from the previous 4 weeks to ever (11, 19). Several studies asked participants about nonprescription use of antibiotics from 1 specific source, such as leftover prescribed antibiotics (9, 12, 13, 17, 40) or antibiotics obtained without a prescription from stores or markets (21, 30, 34). Others (15, 20, 22) asked open-ended questions about potential sources, such as, Where do you regularly get antibiotics? Only 1 study explored intention to use antibiotics without a prescription (20). Prevalence of Nonprescription Antibiotic Use Figure 2 shows the number of studies done in each of the 4 population groups and the prevalence of nonprescription use reported in these studies. Prevalence estimates varied widely, with general populations surveyed outside health care settings having the widest range. The study with the lowest prevalence from this group involved a predominantly white population in Wisconsin and Minnesota, in which 3% of parents of young children reported that they had used antibiotics for themselves or their children without consulting a physician in the previous 6 months (10). The highest estimate (48%) came from a 2018 national Internet survey of parents about pediatric antibiotic diversion (16). Of 219 (48%) who kept leftover antibiotics, 159 (73%) subsequently diverted them to their child's siblings, unrelated children, and unrelated adults (16). Among patients or parents of patients surveyed in health care settings, the lowest reported prevalence was 1% from a study of an adult urban population (19), and the highest estimate (25%) was from a study in primary care patients (20). Figure 2. Prevalence of nonprescription antibiotic use reported in available publications. Numbers correspond to reference citations. Italics indicate national surveys. Several studies (15, 2124) reported that nonprescription antibiotic use was prevalent in Hispanic/Latino populations. The lowest prevalence (19%) was reported in a 2005 survey that included predominantly uninsured Latino patients visiting clinics in South Carolina (21). The highest prevalence (66%) was reported in a 2014 survey of Latino migrant workers in Florida (24). In studies of injection drug users, the prevalence of nonprescription antibiotic use to treat abscesses and injection-related wounds varied from 5% to 32% (2528). Sources and Ty