Consumers increasingly purchase products online; for example, rising from 53% of consumers in the United Kingdom (UK) in 2008 to 87% in 2020 (Office for National Statistics, 2020). Many consumers now prefer to purchase online, including 61.4% in the United States, 57.4% in the UK, 51.6% in Spain, 49.2% in France and Poland, and 47.8% in Australia and Germany (Klarna, 2023). In some countries, many consumers purchase drugs or health products online each year, for example, 43% in Germany, 39% in Mexico, 36% in the UK, 33% in the United States, and 27% in France (Statista Consumer Insights, 2023). Thus, many consumers are turning to online pharmacies to purchase medications.

A survey by the Alliance for Safe Online Pharmacies (2020) found that 35% of American consumers have purchased medication for themselves or someone in their care from an online pharmacy (also known as an e-pharmacy, internet pharmacy, or cyber pharmacy). Online pharmacies sell or dispense pharmaceutical drugs or other government-regulated medical treatments through the internet or electronic media (e.g., websites, social media, or mobile apps). Consumer purchases from online pharmacies continue to grow rapidly due to the convenience, accessibility, and cost savings that they provide (Limbu and Huhmann, 2023b). For example, purchases by Hungarian consumers from online pharmacies increased over tenfold between 2018 and 2020 (Fittler et al., 2022a). Online pharmacies have become a major healthcare resource for consumers, with global sales of US$98.8 billion in 2022, which is expected to reach US$353.9 billion annually by 2032, with a compound annual growth rate (CAGR) of 13.6%. In North America, consumer purchases from online pharmacies are projected to grow from US$39.4 in 2022 to US$138.9 in 2032, with a CAGR of 13.4% (Global Market Insights, 2023).

Online pharmacies include major corporations (e.g., Express Scripts Pharmacy, Walgreens, Amazon Pharmacy, and CVS), smaller independent pharmacies, and even illicit online pharmacies. Illicit online pharmacies violate regulations by selling counterfeit, adulterated, or unapproved drugs or dispensing prescription drugs without a valid prescription (Limbu and Huhmann, 2023a)

Research on online pharmacies has been growing. Reviews of online pharmacies show how the literature documents online pharmacy types and characteristics, the therapeutic classes and quality of drugs available, and risks to patients and public health (Orizio et al., 2011; Mackey and Nayyar, 2016; Long et al., 2022; Limbu and Huhmann, 2023a).

Despite a growing literature stream, a review has yet to be carried out to summarize and synthesize the studies that have examined factors predicting consumers’ online medicine purchase intentions and behavior. Only one review touches on consumer purchases (Almomani et al., 2023b). This narrative review of 17 studies identifies the prevalence of and reasons for prescription medicine purchases using any internet platform, including search engines, social media, and encrypted messaging applications; however, half the qualitative studies reviewed sampled pregnant women, which limits generalizability. Further, it solely focused on studies of prescription medication purchases published between 2012 and 2021. Although Almomani et al.’s (2023b) review included any internet purchases of prescription medications, its narrow search terms missed many studies of online pharmacy purchases. In addition, it included no studies published prior to 2012 or after 2021. Our study reviews almost three times as many studies on online pharmacy purchases alone.

Thus, to better understand why consumers increasingly purchase from online pharmacies, including illicit online pharmacies, the current scoping review rigorously examines all qualitative and quantitative studies of consumers’ online medication purchase intentions and behavior. Unlike earlier reviews, we included studies of consumer purchases of both prescription and over-the-counter (OTC) medications to determine if the need for a prescription alters why consumers want to acquire medication online. Also, we did not constrain our review to studies published within a limited date range. This allowed us to show how research into this topic has changed over time. Thus, this scoping review provides a comprehensive understanding of the nature of research into consumers’ online medication purchases.

Moreover, our review makes an important distinction between influences on consumer purchase intentions and influences on actual purchase behavior. Although some assume purchase intentions predict actual purchase behavior, prior research in many disciplines has found that they are not the same. In fact, meta-analyses have found that intentions account for only 28% of the variance in behavior and that a moderate-to-large change in intentions only results in a small-to-moderate change in behavior (Sheeran, 2002; Webb and Sheeran, 2006). Variables that increase or reduce the relationship between purchase intentions and behavior include unexpected situations, social influence, type of product, intervening time, environmental context, consumers’ self-efficacy, and the receipt of new information (Cote et al., 1985; Morwitz et al., 2007; Sheeran, 2002; Webb and Sheeran, 2006). For example, a consumer may intend to purchase from an online pharmacy, but time or social influence may shift that purchase to a brick-and-mortar pharmacy. Alternatively, a consumer may not intend to purchase from an online pharmacy, but an unexpected situation (e.g., a web search for information on a drug revealing a lower price at an online pharmacy) may encourage online medication purchase behavior.

The current review addresses three key research questions: (1) to what extent have consumer purchase intentions and behavior been investigated as they relate to online pharmacies? (2) how do the antecedents of consumers’ online purchases differ between OTC and prescription medications? and (3) what factors have been identified in the published literature that help explain consumers’ online pharmacy purchase intentions and behavior?

Hence, our investigation aims to fill a research gap by systematically scoping a body of literature on this topic of growing interest to researchers in healthcare and public policy. In addition, we provide guidance for the direction of future research and the areas that remain uninvestigated or unstudied, as well as those that represent emerging topics that warrant greater investigation.

We carried out a scoping review, which is useful to map the literature on evolving or emerging fields or topics (Munn et al., 2018), such as the topic covered in the present study. This scoping review was coducted following the guidelines recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a commonly used reporting guidance for systematic reviews (Liberati et al., 2009). As such, this scoping review applies (Arksey and O’Malley, 2005) five-step framework: (1) research question identification, (2) relevant study identification, (3) study selection via inclusion and exclusion criteria, (4) data charting and investigation, and (5) result presentation.

This scoping review sought to understand the current landscape of empirical research on the drivers of consumer purchase intentions and usage behavior of online pharmacies. Scholarly interest in this topic has been growing exponentially over the last few years. Using rigorous scoping review methods, forty-eight articles published to date met the inclusion criteria, including 12 published in 2023.

Although we sought qualitative and quantitative studies that applied various methodological approaches, the existing literature was mostly limited to surveys. In terms of sample populations, however, the existing literature exhibits greater diversity in both population types (e.g., adults, patients, pregnant women) and geographic areas, such as Europe (e.g., Germany, Hungary, Ireland, Malta, Netherlands, Portugal, Romania, Russia, Slovenia, Sweden, and the UK), Asia (e.g., Bangladesh, India, China, and Taiwan), North America (Canada and the United States), the Arabian Peninsula (e.g., Saudi Arabia and the United Arab Emirates), Africa (e.g., Egypt and Nigeria), and Australia. However, Latin America has been ignored in the existing literature, including the major markets of Mexico, Brazil, Chile, Colombia, and Argentina.

This scoping review identified twelve general factors, which include many individual facilitators and inhibitors of consumer purchase intentions and behavior that have been studied so far (Table 3). Of these, the greatest amount of research has investigated the demographics of consumers who purchase or intend to purchase from online pharmacies. Due to the conflicting results, few implications can be gleaned from the prior research related to demographics or the role of health insurance coverage. However, higher-income consumers, White American consumers, and more educated consumers (in nine of ten studies) had higher online medication purchase intentions and behavior. The implication for researchers and practitioners from the income and education findings seems to be that greater financial and cognitive resources help consumers navigate the online environment to find medications for purchase. Policymakers seeking to dissuade purchases from rogue or illegitimate online pharmacies should target messages and campaigns to these demographic groups.

Convenience and availability factors more consistently influenced online medication purchase intentions and behavior. Consumers intended or chose to purchase from online pharmacies due to faster and more convenient delivery, ease of use and gathering information, accessibility, the ability to bypass healthcare providers or regulatory gatekeepers, availability outside of store hours, and access to medications unavailable locally. A practical implication for brick-and-mortar pharmacies is that enhancing their convenience (e.g., same day delivery, faster service at the pharmacy counter, or longer hours of operation) should help them better compete with online pharmacies.

Price was also a consistent influence on online medication purchase intentions and behavior. Factors that lowered prices or increased price savings and value received from online medicine purchases tended to attract consumers. Thus, a practical implication is that online pharmacies should emphasize price savings to continue to grow their share of consumers’ drug purchases. To better challenge online pharmacies, brick-and-mortar pharmacies should become more price competitive. A policy implication is that public policymakers and regulators attempting to control the illicit dispensing of medicine online should consider regulation reductions, subsidies, or other ways to lower prices through legitimate pharmacies.

Favorable evaluations of the purchase environment also consistently benefitted purchase intentions and behavior across many types of evaluations, such as attitudes, trust, emotional response, aesthetically pleasing and functional design evaluations, enjoyment, and satisfaction. Thus, it appears that many consumers who purchase from or intend to purchase from online pharmacies do so because they hold positive evaluations of those pharmacies. An important implication of this finding is that policymakers, regulators, and brick-and-mortar pharmacies interested in discouraging online medication purchases must engage in attitude change campaigns before expecting consumers who purchase online to alter their intentions or behavior. Attitude change can take time as it requires learning new information and responses through repeated exposure to counterinformation or social influence from family, friends, or trusted others, such as experts or celebrities.

This scoping review summarized prior research findings in which social influence and other information sources motivate online medication purchase intentions and behavior. Intentions and behavior were influenced by information and recommendations from expert sources, such as healthcare providers and websites with drug information; personal sources, such as friends and family; independent sources, such as social media influencers and reviews by other consumers; and non-personal sources, such as social media marketing. One implication is that pharmacists, healthcare providers, policymakers, and regulators should be able to indirectly influence consumer behavior toward online medicine purchases if they tap into the social and normative influence of one or more of these information sources.

Perceived financial, physical, or source risks inhibit online medicine purchase intentions and behavior, whereas greater health literacy and experience with online pharmacies, online shopping in general, and the internet or social media encourage online medicine purchasing. The benefits of online pharmacies (e.g., greater perceptions of anonymity or privacy, better perceived product quality, and more product variety) also encourage online medicine purchase intentions and behavior. An implication is that brick-and-mortar competitors or public policymakers should heighten consumer awareness of these risks if they wish to discourage consumer online medicine purchases. Further, legitimate online sellers can highlight risks to differentiate their verified online pharmacies from illicit or rogue online pharmacies.

Finally, this scoping review documented other factors that had been investigated sparingly (see Appendix A). For example, some studies have begun to investigate how consumer personality predisposes some consumers toward (e.g., greater purchase involvement, variety seeking, and openness) or against (e.g., objectivism) online medicine purchasing. Other studies have begun to investigate situational influences on consumer online medication purchase intentions and behavior (e.g., the COVID-19 pandemic). Individually, these other factors have been studied so rarely that it is difficult to confidently predict the general effect on purchase intentions and behavior without future research. These other influences are listed in the Appendix A.

The analyzed literature indicates several gaps in the literature and future research directions that could be addressed. First, although this scoping review covers the vast majority of the literature published in English to date on consumers’ online medication purchase intentions and behavior, research interest in this topic is growing exponentially, with several new studies published each year. Thus, a systematic review or meta-analysis that incorporates the post-2023 studies will likely be able to be conducted within the next decade once sufficient research has been published. This should further our understanding of the factors that facilitate and inhibit online medication purchasing as well as help determine the relative strength of different influences.

Second, this scoping review found that the current state of research into the drivers of consumers’ online medication purchase intentions and behavior is methodologically limited. Most studies (87.5%) use a survey design. The remainder includes a handful of qualitative studies and a single experiment. Future research employing methods other than surveys (e.g., experiments, observational methods, and data analytics) can investigate research topics that are difficult to study via self-report methods. Similarly, future research should advance the understanding of online purchase drivers by using more generalizable and diverse samples, patient rather than general adult samples, and samples that permit cross-cultural comparisons. Future research could also investigate more complex models of potential drivers’ relationships with purchase intentions and/or behavior, such as mediation or moderation models that could resolve the conflicting evidence in prior research that this scoping review has uncovered and identify important boundary conditions on these effects.

Third, this scoping review finds that a vast majority of the prior research did not specify whether online purchases of OTC or prescription medication or both were being studied. Future research should specify this because the current review shows differences in the drivers of online OTC and prescription drug purchase intentions and behavior. In fact, due to the paucity of literature on this issue, future research is needed to more confidently delineate the drivers of consumers’ online purchase intentions and behavior for OTC versus prescription drugs.

Fourth, demographics (e.g., consumers’ age, gender, or educational attainment) are easy to measure but appear to be poor predictors of purchase intentions or behavior, given the large number of conflicting results related to demographic variables in the studies reviewed. As noted in previous reviews (Tugwell et al., 2008; Schmid et al., 2017; Limbu and Huhmann, 2023c), demographic variables are carrier variables that are not mechanisms causing changes in intentions or behavior but are instead associated to some degree with the prior experiences, predispositions, beliefs, attitudes, or characteristics that affect consumer response. Thus, rather than relying on demographics, future research should attempt to identify the underlying explanatory determinants to better predict purchase intentions and behavior from online pharmacies. Studies, including moderation or mediation tests, could also help better understand the mechanisms at work. Once the underlying explanatory determinants associated with a demographic variable such as age or gender have been identified, the indirectly related demographic variables can serve to identify likely target audiences for public health campaigns and patient education materials regarding online pharmacies.

Fifth, although this scoping review documents many influences that increase or decrease consumers’ purchase intentions and/or behavior, it also underscores the need for future research into uninvestigated and understudied influences. For example, psychographic variables, such as personality, perceptions, attitudes, beliefs, lifestyle, interests, and values, can offer the potential to identify deeper motivations and could better identify why some consumers buy medications online whereas others do not. To direct future research into other uninvestigated or underinvestigated areas, Table 4 lists some research questions that warrant exploration to better understand the driving influences on consumer purchase intentions and behavior.

Finally, the prior literature uncovered by this scoping review tends to be atheoretical and exhibits a general lack of definitions for key constructs posited as factors influencing consumer purchase intentions or behavior. To aid pharmacology researchers and investigators from other fields, the research questions in Table 4 are linked to theories and well-defined constructs in the literature from psychology, consumer research, advertising, health communication, and marketing. For example, Fittler et al. (2022b) showed that unlicensed drug distributors use search engine results to redirect site visitors to illegal online pharmacies. Using the constructs from the marketing literature of search engine optimization and search engine marketing, how can legal sellers take action against these rogue sites and use search engine results to promote medication purchases from legitimate online and brick-and-mortar pharmacies? Future research should define the constructs studied and use these theories to establish consistent terminology that will ease comparison across studies to advance understanding of the underlying drivers of consumers’ online medication purchase intentions and behavior.

This scoping review examined studies of consumers’ online pharmacy purchase intentions and behavior. While demographic factors tended to be the most often measured influences on intentions and behavior, their role was generally inconsistent, with many contradictory results. However, other factors (e.g., convenience, availability, lower prices, favorable evaluations of the purchase environment, and supportive recommendations from others) more consistently enhanced online medication purchase intentions and behavior. These findings of our scoping review should aid verified online pharmacies and brick-and-mortar stores in understanding ways to encourage consumer medication purchases.

Further, our scoping review revealed a general lack of definitions for constructs studied and a paucity of theoretical justification as to why certain factors or individual influences should affect purchase intentions or behavior. This, combined with gaps in the existing literature, led us to develop an extensive agenda for future research to advance our understanding of the drivers of consumers’ intentions and behavior toward online pharmacy purchases. This research agenda should help future studies in this area move beyond descriptive analysis to theory-testing and discovering the underlying explanations of how specific influences affect online medication purchase intentions and behaviors. To accomplish this, these future research directions are based on theories and concepts developed in other areas focused on stimulating intentions or prompting behaviors (e.g., psychology, consumer research, advertising, health communication, and marketing). Investigating research questions based on this agenda should help healthcare providers, public policymakers, and regulators design more effective interventions to promote more positive individual patient and public health outcomes as well as benefit researchers interested in this topic of increasing interest and economic importance.