A Just Transgression of AMR Governance? How Mexico City’s Informal Medicine Sellers Balance Antibiotic Care and Control by Bending the Rules

Abstract

This article explores how informal medicine sellers (IMSs) in Mexico City “contest” and “reassemble” antibiotic control standards in ways that both challenge and respond to antimicrobial resistance (AMR) governance. Drawing on ethnographic fieldwork, we examine the “rationales”—moral, political, economic, technoscientific, and practical—that IMSs invoke to justify bypassing antibiotic prescription, dispensing and accounting regulations, and the “practical tinkering” they perform to make antibiotics available and “appropriately” used under conditions of scarcity and oversight failure. Rather than viewing IMSs as simply breaking official rules, we adopt a “social life of standards” perspective to argue that their actions reflect localized enactments of antibiotic control—versions shaped by community needs, corruption, poverty, and distrust in public health infrastructures. These practices are ambivalent, blurring boundaries between public service and profit and systemic subversion and informal regulation. By tracking how IMSs adapt, collectivize, and sometimes deliver treatments, we show how antibiotic governance is reworked from below—not only in response to AMR, but also to structural exclusions from formal care. We argue that rather than treating IMS rationales and practices as part of the problem, they should be studied as grounded responses to systemic failure—and potential sources of insight for context-sensitive regulatory design.

Informal medicine sellers (IMSs) occupy a strategic, yet ambivalent position in the fight against antimicrobial resistance (AMR). In many low- and middle-income countries, they increase the accessibility and affordability of lifesaving medicines, provide trusted, sometimes-first-response care, and frequently make up for public health system dysfunction.¹ Yet, working informally—outside strict official oversight and often without requisite qualifications—IMSs are associated with nonprescription antibiotic dispensing, considered a driver of inappropriate antibiotic use and AMR.² This ambivalence poses a dilemma for AMR responses: cracking down on IMSs may seem an effective measure to regulate antibiotic consumption more strictly, but it may also reduce antibiotic access for populations lacking equitable access, potentially causing more harm than good.³

IMSs in Mexico City illustrate this tension. Research directly examining Mexico’s informal pharmaceutical trade remains scant.⁴ However, recent journalistic reporting suggests that IMSs helped meet demand left by medicine shortages and coverage interruptions resulting from poorly planned health system reforms.⁵ Yet, the very existence of IMSs—working in unregistered outlets, routinely bypassing antibiotic dispensing standards—challenges regulations established to combat AMR.⁶ Nevertheless, given that they may both (a) increase access to antibiotics amid public pharmaceutical shortages and (b) make them more affordable amid a prolonged economic downturn and increasing health expenditures, their ambivalence persists.⁷

AMR, a serious public health threat in Mexico, has attracted significant regulatory attention. In 2019, approximately 70,100 people died from AMR-related causes.⁸ In 2010, Mexico’s Ministry of Health made prescriptions for antibiotics mandatory, to reduce “… self-prescription, inappropriate use and the development of resistance.”⁹ In 2018, COFEPRIS (Mexico’s national medicines authority) and a “committee of experts” introduced the “Control of Antibiotics” framework.¹⁰ These regulations for pharmaceutical outlets aimed to strengthen the 2010 prescription requirement by imposing standard procedures on dispensing, including registering and keeping antibiotic prescriptions for audit purposes.¹¹ Yet, conditions at street level suggest significant implementation obstacles.

Cori Hayden has highlighted the longstanding practical absence of pharmaceutical regulation in Mexico City’s barrios—as one informant stated “… anyone can open a pharmacy, anywhere!”¹² This reported free-for-all pharmaceutical economy suggests that many unregistered pharmaceutical outlets are “invisible” to the authorities, rendering prescription audits practically impossible and associated regulations, “paper tigers.”¹³ Indeed, the existence of medicine street markets reflects significant oversight gaps in Mexico City and the diverse shapes informal pharmaceutical commerce can take.¹⁴ Ultimately, this situation indicates that total enforcement of antibiotic control regulations would require a clampdown on any and every commercial pharmaceutical outlet.

Suggesting a middle ground, recent scholarship shows growing support for building alliances with retail-level actors to optimize antimicrobial dispensing and use within communities.¹⁵ Educational interventions, key to creating these alliances, have yielded positive results, yet also have drawbacks: bringing community-level actors’ practices closer to the norm without understanding and integrating what works for them risks sidelining their context-specific know-how.¹⁶ Furthermore, as educational interventions gained popularity, few have questioned whether what is deemed appropriate from a regulatory standpoint is practically and financially feasible for IMSs: whether behavioral approaches can overcome structural barriers, if what is appropriate from above is appropriate at street level, and if care sometimes means amending or bypassing standards and regulations.¹⁷

Our article builds on ethnographic fieldwork and semistructured interviews with IMSs in Mexico City to explore this problem-space. Adopting a “social life of standards” perspective, we explain the “rationales” IMSs invoke to justify their informal practices.¹⁸ We present them non-normatively, while acknowledging their “ambivalence”: sellers blur the line between acting as a public health resource in an underperforming system and running a private business in a permissive regulatory environment.¹⁹ Then, we show that through their antibiotic-centered practices, they do not simply break rules. Rather, IMSs “reassemble” antibiotic control standards into versions that fit their livelihoods and communities’ needs.²⁰ To conclude, we emphasize that corruption and inequalities in access to healthcare, and top-down regulations that ignore these realities generate a healthcare landscape where rule-bending becomes a moral imperative.

1. Theoretical background

1.1. The entwinements and ambivalences of informality

The concept of “informality” draws analytical attention to modes of social organization and practice that differ from official bureaucratic requirements, such as legislation and regulation, in contexts where similar activities or social formations typically comply.²¹ Phenomena classified as “informal” are generally understood to be (a) pragmatic and makeshift rather than rationalized or systematically planned and organized following preset principles; (b) unwritten, unregistered, or lacking formal representation; and (c) semiclandestine, existing outside state-backed legitimacy or in defiance of established rules.²²

Despite their binarism, however, formality and informality have long been understood as intertwined, co-constituted, and mutually dependent.²³ With the institutionalization of every new rule, law, procedure, or standard, arises a possibility—and sometimes an incentive—to bypass or break it.²⁴ Substantial scholarship examines how formal structures are made to work informally, and vice versa. ²⁵ These entwinements hint at a formal-to-informal continuum rather than a dichotomy, with context-bound dynamics.²⁶

An additional layer of complexity is the “ambivalence” of informal practices, which operate with “double standard,” “double deed,” and “double incentive.”²⁷ Such logics underlie informal practices and ways of communicating them.²⁸ Herein, we highlight three types: (1) “normative,” where a practitioner’s identity shapes a practice’s morality, (2) “functional,” where bypassing systemic obstacles to access specific resources both subverts and supports formal structures; and (3) “motivational,” where practices seem driven by both public and private interests.²⁹

Understanding the informality of IMSs from this perspective allows us to acknowledge them as self-interested economic actors in unregulated—but sometimes necessary—markets, who are also deeply embedded in their communities and oftentimes invested in their care. This perspective, thus, enriches previous portrayals that tended to represent them as primarily one or the other.³⁰ Fundamental to our analysis is that “[in]formality is grounded in the human ability to justify subverting constraints,” often through appeals to context-specific exceptionality such as friendship or necessity.³¹

In the following subsection, we explain our treatment of the concept of ‘rationale’ as a particular expression of situated reasoning used to justify contextualized pharmaceutical practices, in contrast to official ‘rationality.’

1.2. Official rationality, rationales, and antibiotic-centered practices

The “rational use of drugs” has been defined as a “dominant normative framework” that prescribes and justifies promoting “… the judicious prescription by well-informed professionals of well-studied drugs to well-informed patients for well-defined conditions.”³² Its corollary—practices that deviate from this are irrational—has been criticized for limiting understanding of real-world pharmaceutical consumption and prescription practices, including underlying “rationales” shaped by “… individual and local logics, representations, incentives, and constraints….”³³ Furthermore, “irrationality” has been criticized for characterizing populations in the Global South as composed of “deficient” subjects whose “misbehavior” and lack of appropriate knowledge, expressed in their use of antibiotics, must be managed.³⁴ The term “rationale” highlights the situated reasoning that informs antibiotic-centered practices that deviate from the officially ‘rational’ or ‘appropriate’.³⁵

A growing body of literature explores why health professionals and patients stray from clinical guidelines, antibiotic regulations, and prescriptions.³⁶ Among prescribers, adjusting to patients’ treatment-seeking behavior and practical constraints (e.g., staff shortages or time constraints) are common justifications.³⁷ Health professionals have expressed criticism of top-down antibiotic policies without context-sensitive adjustments and attention to systemic issues.³⁸ Among patient rationales for antibiotic use, Rodrigues found that familiarity with typical uses of certain antibiotics, repetition and adjustment of previously prescribed treatments, and advice from dispensers or the internet often shaped patients’ situated reasoning.³⁹ Primarily explored among prescribers and patients, the term “rationale” thus encompasses moral, political, economic, technoscientific, and practical judgments grounded in empirical knowledge.

Research examining rationales that IMSs hold for challenging antibiotic regulations is limited and skewed in two ways. Firstly, IMSs are mainly portrayed as driven by economic or social motives, without being credited with the capacity to reflect on their ambivalent positions providing care-for-profit in the unregulated sector.⁴⁰ Secondly, widespread findings of limited knowledge about antibiotics and regulations among community-level healthcare providers may have discouraged deeper inquiry into their views on specific regulatory items like prescription requirements.⁴¹

However, Álvarez’s journalistic account from a Mexican street market suggested such an investigation was possible: an IMS reported that their medicines were not and could not have been stolen from public institutions because the health sector suffered shortages of those medicines.⁴² Another seller mentioned keeping medicines in the shade.⁴³ These accounts signaled two insights: (1) that medicine sellers were capable of critiquing public healthcare, legitimizing their products and practices and (2) that while pharmaceutical risks could be framed as “science-driven scenarios,” they were also proximate, everyday concerns.⁴⁴ Concretely, keeping medicines in the shade suggested a rudimentary attempt to prevent environmental conditions from degrading medicines.⁴⁵ Álvarez’s account of IMSs’ informal practices, including local adaptations of official standards, informed this research and its central analytic themes.

1.3. Tinkering-with and reassembling standards

Standards and technical regulations can be thought of as rules, usually codified or formally represented, that apply to both things and people.⁴⁶ “They are crucial to the regulation of safe and effective technologies and key for the legitimization of evidence and expertise.”⁴⁷ They are often presented as “universal” and grounded in scientific evidence and paraphernalia to bolster their authority.⁴⁸ In practice, however, their universality runs into context-specific implementation obstacles.⁴⁹

When this happens, “practical tinkering” becomes necessary to adjust situated practice to the standard and vice versa. ⁵⁰ Recent scholarship on “the social life of standards” explores how these sociomaterial rules are adapted and localized beyond the imagined, perfectly fitting spaces where they are supposed to be implemented.⁵¹ Depending on how standards are put in practice relative to their original schematic form, invoking Graham et al.’s analytic vocabulary, standards are “subverted,” when they are “… covertly … manipulated so that they can continue within power discourses while being adapted for the local context,” and “contested,” when they are “subjected to overt political conflict … [and] overtly disrupted.”⁵²

Because standards exist on paper and are enacted in objects and practices, they can be “reassembled” in two ways.⁵³ Whereas Graham et al. generally use the term to signal processes of modifying standards as texts or schematic forms through legal procedures, we draw on Busch and Suzuki, who suggest that “practical tinkering” generates enactments that change the “script,” much like when actors improvise dialogue.⁵⁴ Through this process, standards become “localized” into specific environments and undergo a ‘practical reassemblage.’⁵⁵

This study contributes to these discussions by studying how IMSs’ antibiotic-centered practices represent localized enactments of official antibiotic control standards, adapted to fit marginal urban contexts and legitimized by local rationales contesting their official versions. By adopting this perspective, we do not suggest that IMS practices are always similarly effective at mitigating public health risks as fully compliant pharmaceutical practice is. Indeed, we highlight key ambivalences and potential risks. However, we emphasize that, despite lacking formal training, IMSs can use their experience and knowledge to generate their own regulatory forms, which can serve to inform context-sensitive policy interventions.

In the next sections, we outline the socioeconomic and healthcare context of Mexico City’s informal care market and the methods used in this study.

2. Setting

The Mexico City Metropolitan Area (MCMA) encompasses approximately 21.8 million people living in Mexico City proper and the adjacent urban sprawl of small cities and semirural settlements.⁵⁶ The region’s healthcare landscape reflects the plurality, fragmentation, and systemic exclusions of Mexico’s national health system.⁵⁷

The MCMA contains major public hospitals and clinics (many with attached pharmacies), private hospitals and practices, and numerous private pharmacies, some with annexed consultation rooms.⁵⁸ Historically, formal employees in the public and private sectors with “contributive” social security have been prioritized, leaving millions of residents without employment-based social security with unequal access to formal healthcare.⁵⁹ Instead, they depend on “public charity,” remedial universal coverage schemes, and the private sector for healthcare.⁶⁰ Additionally, shortcomings affecting the public system make private care increasingly attractive to insured patients.⁶¹

Hence, as Osorio and Hayden reported, pharmacies with consultation rooms—particularly generics pharmacies—have become a crucial, low-cost alternative to public primary care.⁶² “Mom-and-pop” medicine shops—with and without consultation rooms—offer livelihood opportunities to small-scale entrepreneurs, retirees, medical students awaiting diplomas, and underemployed physicians.⁶³ However, despite their importance as health resources and livelihood strategies, pharmacies-with-consultation-rooms have been criticized for ‘promoting inequity’ because they depend on patients’ out-of-pocket spending and the state’s failure to provide high-quality, reliable, universal healthcare.⁶⁴

This public–private mixture of providers has made “contributive” social security coverage or the “capacity-to-pay” key barriers to accessing healthcare, especially since recent system-wide reforms.⁶⁵ Nationwide, between 2018 and 2024, the number of people lacking access to public healthcare nearly doubled to more than 44 million.⁶⁶ This coincided with the dismantling of Seguro Popular—a universal coverage scheme created in 2003 for those without contributive social security.⁶⁷ Over the same period, households’ out-of-pocket health expenditures increased by 41.4% nationwide, largely due to the doubling of household spending on medicines.⁶⁸ These increases coincided with efforts to centralize public pharmaceutical procurement and distribution—a process that, alongside the COVID-19 pandemic, exacerbated medicine shortages across the country.⁶⁹ These broader developments influenced the MCMA’s informal healthcare market. Reduced access to public medical care and widespread medicine shortages have reportedly stimulated demand for pharmaceuticals in the so-called “black market.”⁷⁰

Despite being understudied, the region’s informal healthcare market includes forms of pharmaceutical commerce beyond ‘mom-and-pop’ drug shops, namely in food markets and street markets.⁷¹ Although these outlets may share similarities with informal pharmacies, the absence of consultation rooms and on-site physicians generates greater variability in, and concerns about, the quality of their services and products.⁷² Faltering medical and regulatory oversight can explain reports of them selling controlled pharmaceuticals, including antibiotics, without medical prescriptions.⁷³

3. Methods

This article draws on two months of ethnographic fieldwork conducted across various informal pharmaceutical outlets (i.e. not registered with COFEPRIS) across the MCMA. Our methodological approach built on RRG’s pre-existing social ties with the participants and background knowledge of their workplaces, as a native of Mexico City with family ties to the informal economy. Given the semiclandestine nature of this trade, recruitment relied on personal networks, street canvassing, and snowball sampling. The main inclusion criteria were that participants were adults (18+) involved in operating informal pharmaceutical outlets (IMSs and helpers) or in supplying medicines to an IMS (suppliers).

Fieldwork began in the public food market of La Merced (central Mexico City), and the street market of El Salado, east of the city. Using a “follow the medicine” approach, we identified other actors, places, and processes involved in the circulation of pharmaceuticals.⁷⁴ This ‘revealed’ additional street markets and unlicensed pharmacies, and customers, medicine sellers, and medical professionals who often acted as suppliers to informal pharmaceutical outlets. In total, five IMSs operating a total of 16 informal outlets, one helper, and two suppliers were included as core participants.

Two principal research techniques—‘deep hanging out’ and “go-alongs”—enabled sustained, everyday engagement with sellers as they sourced, stocked, and sold medicines, providing insight into their handling of pharmaceuticals, interpretation of regulatory issues, dealings with authorities, commercial strategies, and interactions with customers.⁷⁵ They also provided insight into the routines of the helper and suppliers. Data collection included detailed fieldnotes from participant observation and informal conversations, and audio-recorded semistructured interviews exploring how participants navigated obtaining, transporting, storing, prescribing, selling, licensing, and disposing of medicines. Long hours in each outlet facilitated informal conversations with customers and brief interviews with actors shaping the local care ecosystem, including one medicine seller who did not want to be recorded but answered some questions via text message and a doctor who answered questions by phone. These exchanges contextualized participants’ narratives and practices. Research additionally included a review of key regulatory documents, such as Mexico’s General Law of Health and the Pharmacopoeia’s Supplement for medicine-selling establishments, to contrast formal expectations with street-level practices.⁷⁶

Interviews were conducted in Spanish and later translated with attention to tone and context. Data were thematically analyzed using an “inductive and deductive” approach.⁷⁷ Ethical protocols included pseudonymization of all names and maintaining ongoing informed consent.

In the following sections, we draw on the cases of Marcelo and Sergio—two cousins in a family that has adopted pharmaceutical commerce as the family business. Marcelo, in his late 50s, studied Communication, and was the family’s first pharmaceutical entrepreneur.⁷⁸ He built a small empire of unlicensed drug shops in the outskirts of the city and introduced his brothers and cousins to the trade.⁷⁹ Sergio, a few years younger, was a potato seller in the city center before becoming a medicine seller.⁸⁰ He entered the business after Marcelo attempted to set up a small “pharmacy” in the stall next to his and abandoned it due to low returns.⁸¹ Left with Marcelo’s remaining stock, Sergio kept the business going by sourcing medicines at his cousin’s usual suppliers.⁸² At the time of this study, their businesses were already established and operated independently.

We begin by examining Marcelo’s critiques of antibiotic regulations and analyze the ambivalences embedded in the rationales he presents as justifications to bypass them. Then, we follow Sergio and his helper Gloria’s work in the food market of La Merced, where they adapt antibiotic-related standards to local beliefs, financial constraints, and healthcare access limitations.

4. Contesting antibiotic control in the street

In 2024, Marcelo had almost 20 years of experience in the business.⁸³ He had set up each of his drug shops himself, adapting the space, tending the counter, hiring personnel, and eventually transitioning into more of a managerial and administrative role—except for his main shop, which operated out of a couple of storefronts annexed to his house.⁸⁴ Marcelo occasionally worked the counter and used his main establishment to test business ideas, such as a naturist medicine and supplement shop, which he established in a storefront that had previously housed an annexed consultation room, where he had employed several doctors over the years (see Section 2.).⁸⁵ However, around 2016, he moved away from employing doctors in his businesses.⁸⁶ By 2024, his six locations were standalone drug shops.⁸⁷

Marcelo holds himself and his employees to a “decalogue” of service standards, according to him, pasted near the counter of all his establishments.⁸⁸ The one in his main pharmacy had nine items, including “Always call [Marcelo] if we don’t have the medicine and ask if we can get it” or “If a client is missing 1, 2 or 3 pesos to buy their product, tell them don’t worry they can leave it later” (see Figure 1).⁸⁹ In his words: “… to be a pharmacist is a great commitment—like [Spiderman’s] Uncle Ben would say—‘with great power comes great responsibility’.”⁹⁰

Figure 1. Marcelo’s customer service decalogue. Digital photo by RRG, unlicensed pharmacy in the outskirts of Mexico City, April 16, 2024.

Marcelo had his own standards surrounding antibiotics too. Despite bypassing most antibiotic control regulations, selling them “indiscriminately,” he could explain why this was and should be the case.⁹¹ His rationales were complex and layered, embedded in the context where his pharmacies operated and grounded in his experience working the counter. We present them in the order of importance Marcelo gave them.

4.1. Corruption makes antibiotic regulations just tools for extortion

Marcelo seemed to hold 2018’s Control of Antibiotics regulations in special contempt, and his rationale to bypass them was that they provided government inspectors just another avenue to extort his business.

Regulations mandate that pharmacy audits are conducted by COFEPRIS or state health authorities to check for integral compliance with pharmaceutical outlet regulations.⁹² In Marcelo’s experience, however, inspectors primarily used these audits to make a quick buck by identifying or making up irregularities and asking for payoffs so establishments could get off the hook. Actual compliance with regulations, he reported, was of secondary importance: “If they feel like it, you won’t pass.”⁹³ Thus, Marcelo described that Control of Antibiotics regulations, in practice, was just an instrument for predatory government employees to extract “tolls.”⁹⁴

… you’re supposed to keep a record of medications like an accountant, but that book is just so that COFEPRIS knows how you’re managing antibiotics … How many antibiotics came in? How many went out? How many with a prescription? …

—And how do you handle that? [RRG]

—Well, you don’t do anything. … Everything gets handled once the COFEPRIS guy shows up. … Pay them, and if someone else comes by for an inspection, you tell them: “the other guy already came—nothing to worry about.” . … They measure everything. Literally everything. … And things that don’t fall under their scope. … [COFEPRIS inspectors] come for their yearly or semiannual fee. … They’ll find a way to mess with you. Or maybe they won’t. … Why risk it? They take 5,000 pesos [US$260] from me every two or six months. … Now they just show up all cheeky and say, “How are we doing? Six months have passed. Time flies, right?” And they’ll want to raise the fee. It’s extortion.⁹⁵

Although Marcelo called these transactions “extortions,” they seemed to allow his pharmacy empire to continue operating despite its minimal compliance with regulations. Interpreted from the perspective of state visibility, two layers of concealment enabled Marcelo’s business.⁹⁶ One was his lacking registration with COFEPRIS, reducing chances his establishments appeared on the authorities’ radar; the other involved inspectors’ discretionary practices, which invisibilized his spotted establishments from COFEPRIS to hold them hostage and continuously extract a toll so routinized and brazenly requested that Marcelo called it a “fee.”

According to Marcelo’s account, what were basically pharmacy requisites for “antibiotic accounting,” and other regulations became “subverted” by these informal transactions.⁹⁷ They allowed inspectors to enrich themselves in exchange for helping Marcelo conceal his noncompliance, and for the business to continue as usual, as if regulations had been implemented.

The transaction described above is marked by “motivational” and “normative ambivalence,” because Marcelo participated in—and benefitted from—an act he dubbed inspectors’ abusive behavior and coercion, omitting his possible collusion therein.⁹⁸ Regardless of how Marcelo actually participated in these transactions, analyzing them as his rationale to bypass burdensome requisites reveals a situated, informal logic. If, as Marcelo says, inspectors do not check for compliance or are willing to make up violations, prescription registering and antibiotic accounting are pointless activities.

4.2. The prescription requirement unnecessarily excludes the poor from buying antibiotics

Marcelo’s rationale to bypass the prescription requirement was that it ignored conditions at street level, limiting access to antibiotics without actually optimizing their use in the public.⁹⁹ His critique and efforts to practically amend it showed that Marcelo understood and accepted the risk these regulations aimed to mitigate—AMR—but contested and adapted the mechanism through which they intended to act.

Sometimes governments do things … without understanding the people in that milieu. They do it at scale, from above. … They launched their law and said… “you can’t sell antibiotics because people are becoming resistant to them, because they buy them without a prescription.” … False! The problem [is when] … a doctor sends you five ampicillin injections … which should end your problem. At the second one, you feel better already and say, “Oh, it hurts, I’m not getting the third one.” You don’t finish the treatment, so … the bacteria grow resistant to the medicine, so then when you give it ampicillin again, you say, “it won’t do anything”. What’s happened is the bacteria have vaccinated themselves against the antibiotic, too. It’s a natural process common to all living beings. I protect myself, too.¹⁰⁰

A deep distrust of the state’s capacity to understand the problem at a basic scientific level informed Marcelo’s contesting of the prescription requirement. Even though Control of Antibiotics regulations in Mexico do not operate with the mischaracterization Marcelo described (that people become resistant to antibiotics), some confusion did attend the initial rollout of the prescription requirement. The then-head of COFEPRIS declared in a newspaper that “… people that take antibiotics become immune and resistant towards bacteria they did not have ….”¹⁰¹ Marcelo’s skepticism extended into explicitly contesting the measures the government had taken, placing the responsibility on pharmacies to regulate the flow of antibiotics into the public instead of making doctors “conscientize” patients on how to properly use them.¹⁰²

Ultimately, for Marcelo, it was not access to antibiotics which had to be regulated, but their use. This form of blame-shifting toward consumers has been a common fixture of AMR-related initiatives.¹⁰³ Marcelo partially reproduced it and limited his responsibility to promoting more rational antibiotic use.

When … I was at the counter, I told them: “You’re going to feel better after the first or second [dose] but don’t interrupt the treatment because these medicines are already very strong. Imagine that after this you have to go to the hospital because you won’t be able to get better at home.” So, then it’s about making people conscious about what they’re taking and why they’re taking it.¹⁰⁴

For Marcelo, the prescription requirement seemed to be overkill, which he corrected by selling antibiotics without a prescription but reminding his customers to finish their treatments: his own “contested” version of antibiotic control.¹⁰⁵ Reminding people to adhere to their treatments mimicked standard pharmaceutical deontology, which includes promoting rational use, but differed from it in two crucial ways.¹⁰⁶ Firstly, he sold antibiotics without requesting a medical prescription, and secondly, he recommended antibiotic courses himself.¹⁰⁷ At play was a complex layering of ethical-economic reasoning and self-ascribed lay expertise (addressed in the following section).

The prescription requirement did not consider the financial limitations of his clientele, Marcelo explained, which his version of antibiotic control did: “The problem is not that I indiscriminately sell antibiotics. That’s actually super good, because a lot of people don’t have the resources to go to the doctor. Either they go to the doctor or they fill a prescription. So that’s my excuse.”¹⁰⁸

Thus, Marcelo’s rationale and his version of antibiotic control cast his indiscriminate antibiotic selling as a public service. He simultaneously undermined and complemented the formal healthcare system by violating its regulations and making up for its shortcomings. By reminding people to finish their treatments without checking if they actually had medical prescriptions, Marcelo (1) did his share of risk communication; (2) gave patients access to antibiotics without forcing them to provide proof that they had incurred expenses to see a doctor; and (3) removed a commercial barrier for his business. Marcelo’s “contested” version of antibiotic control, then, was functionally and motivationally ambivalent.¹⁰⁹

His rationale gains weight considering the broader healthcare context in Mexico, where out-of-pocket spending on health has surged in recent years (see Section 2). One study, for instance, estimated a 20% nationwide increase in excessive health expenditures between 2018 and 2020, disproportionately affecting uninsured households and linked to the termination of Seguro Popular, reductions in the Ministry of Health’s budget, and COVID 19-related service disruptions in public facilities.¹¹⁰ In this context, any opportunity to economize can help.

4.3. An experienced local medicine seller knows better than poorly trained doctors

A final rationale to bypass antibiotic regulations, key to his recommending practices, was that Marcelo considered that doctors were not that well trained in pharmacology. He reckoned that years of self-studying and experience at the counter had taught him how to adjust prescriptions. “They take a year [of pharmacology], or a semester at most.”¹¹¹

I really had to study [the PLM, a pharmaceutical reference manual] to be able to make recommendations. … Experience with other doctors [also helped]. … People started trusting me a lot … someone would come in who hadn’t found me [at the counter], go to the doctor and come back … I’d say: “I don’t like this [prescribed] medication.” I would switch it out. … I’d discreetly step into the [annexed] consulting room and tell the doctor, “Doc, … if you give [this medication] every 8 hours, you’re going to kill him.” … I was basically teaching the doctor at that point.¹¹²

These recommendations eventually creeped into prescribing. When we met Marcelo, he was often occupied with the finances of his pharmacies, but a phone call with Sergio, his IMS cousin, revealed how his prescribing operated:

— Good morning mai … A lady just called me whose husband cut his hand. She forgot or lost track of it and fed him bacon. [Sergio]

— Son of a bitch. [Marcelo]

— So he says his hand feels heavy … I told him I don’t know but you who know more … What could you suggest? [Sergio]

— If he’s not allergic, give him ceftriaxone. [Marcelo]¹¹³

Marcelo’s self-appraised lay-expertise, based on his familiarity with medicines and doctors, similar to what Rodrigues observed among patients self-prescribing antibiotics, served as a rationale to take prescribing into his own hands and bypass the prescription requirement.¹¹⁴ In other words, the logic appeared to be why send them to a doctor when I know what they are going to prescribe? Of course, beliefs like those expressed in the phone call—that eating pork with an open wound can lead to infection—suggest these prescribing practices are shaped by criteria that differ from biomedical knowledge, which can lead to unnecessary antibiotic consumption.

This lay-expertise rationale had been elaborated by suggesting that in this outer area of Mexico City, resistance had developed and certain antibiotics had become ineffective. Some doctors, for Marcelo, neither recognized AMR nor adjusted their prescribing practices. To illustrate his point, Marcelo recalled what he used to tell a young doctor, a former employee in one of his pharmacies:

“Doctor … you’re coming from one of those so-called rural clinics where you did your internship, and all they have there is … a very basic stock of medicines. So, you learn with what you have. … Penprocillin, penicillin, ampicillin—the basics [that] don’t do anything for us [people in his area] anymore. We’re already well hardened.” … “You don’t go beyond penicillins.” … “We have amikacin, we have lincomycin.” … It worried me because of my business, you know? … The patient won’t get better, and they’ll have to come back. … It’s not because I want to rotate stock or push my products—it’s because she wasn’t doing her job well. She said: “Why would we drop a bomb on an ant?” “It’s not an ant, doctor! We’re already toughened up! That stuff doesn’t work anymore.”¹¹⁵

Marcelo knew that pressuring the doctor he employed to diversify her prescribing aligned with his commercial interests. Bypassing the prescription requirement generated more demand for different medicines while reducing the risk of less-popular products expiring in his stock. Yet, he maintained that his actions were not motivated by “greed” but addressed a real “need” in his community: cheap access to antibiotics some doctors may not know to prescribe.¹¹⁶

His assertion that in his area, certain antibiotics had stopped working because consumers were “hardened,” appeared to colloquialize his textbook explanation of resistance into an anthropocentric idiom that cast the bodies of his clients as the sites where resistance emerged, instead of bacteria. This subtle modification, a ‘rhetorical-technical tinkering,’ shaped his argumentation.¹¹⁷ Since “… standards invoke the linguistic categories … we use to organize the world,” the shift between the official and colloquial definitions of “resistance” entailed the difference between some infections being resistant, begging case-by-case diagnosis, and all local bodies being hardened, raising suspicion of medical prescriptions unaligned with Marcelo’s “localized” standard treatments.¹¹⁸ This move—perhaps a “use of ignorance” to justify his practices by drawing on a common misunderstanding—took “resistance” from being the main rationale behind Control of Antibiotics regulations to being Marcelo’s rationale to question medical expertise and adapt antibiotic control to his business’, and according to Marcelo, his community’s needs.¹¹⁹

In the following section, we describe how Sergio put Marcelo’s contested version of antibiotic control into practice, by “tinkering” with prescriptions and treatment adherence promotion in the food market of La Merced, central Mexico City.¹²⁰

5. Reassembling antibiotic control in the produce section

Every week, Sergio spends hours taking a knife to small imperfections on his potatoes. Deeming this unnecessary, other potato sellers sometimes make fun of this. When the potatoes are clean, he assembles orders for long-standing clients, delivering them to their businesses across Mexico City, using public transport.¹²¹ Since entering the medicines trade in 2017, Sergio has adapted his work routines and stall to sell medicines alongside potatoes (see Figure 2), fostering a local clientele.¹²² Yet, Marcelo continues to be Sergio’s main source of pharmaceutical knowledge, apart from the internet.¹²³

Figure 2. Box with the legend Antibiotics of Mexico, the name of a generic medicines company, on top of sacks of potatoes. Digital photo by RRG, La Merced market in Mexico City, June 6, 2025.

Among Sergio’s highest-selling products are ceftriaxone injections, oxytetracycline lozenges, and ampicillin tablets—sometimes used as pre-emptive treatments by La Merced’s workers, usually vendors, their helpers, and load haulers who cannot generally afford sick days.¹²⁴

5.1. Standardizing treatments and collectivizing prescriptions

Like Marcelo, Sergio also sold antibiotics without a prescription, or at least a personalized prescription.¹²⁵ Sergio took the few prescriptions he came across, estimated what seemed like an average treatment, and then reused it for several patients.¹²⁶ Sergio’s stall neighbor Gloria’s experience taking antibiotics illustrates this practice. During a “wave of infections” in the market, in November and December of 2023, she got sick and saw a doctor.¹²⁷

Doctor Victor … sent me seven sets of dexamethasone and ceftriaxone. I had to apply them both at the same time. Because [the doctor] sent seven, Sergio told me “No, how can you even think about it? Seven is too strong! Three is enough”. “But the doctor said seven”. “No but it’s too strong, it will harm you, in your body”. So, I listened to him and only got three. And indeed, people came by and only had three in their prescription. I don’t know why I was sent seven.¹²⁸

Sergio’s “tinkering” with Gloria’s prescription was informed by previously encountered prescriptions and by Marcelo’s advice.¹²⁹ Gloria saw this process unfold. While not Sergio’s employee, they had established a close working relationship, a practice common among vendors in La Merced: Gloria occasionally helped Sergio open his stall or deliver medicines, and he helped her move heavy objects and close her stall in the evenings.¹³⁰ An additional perk was Gloria’s famously “good hand” for injections. Sergio sent her “patients” and Gloria charged 20 MXN ($1USD) per injection (see Figure 3).¹³¹

Many customers requested ceftriaxone and dexamethasone, but also alcohol, syringes and cotton balls. … Few came with a prescription. Most [were] in bad shape. “What can you give me?”. [Sergio] would say “No, well it looks like you’re heading that way, your throat hurts, your body… you’re getting [an infection]. Take this”. [Sergio sold] them the package of ceftriaxone with dexamethasone and [cough] syrup, and the Graneodín [lozenges]. … It’s the prescription, he copies the prescriptions. … What they [prescribed] me, he gave everyone. But to me he said, “The prescriptions I’ve been brought have three, so why are you getting seven?”. And then he asked Marcelo, his cousin, the pharmaco-biological chemist [Marcelo studied Communication]: “Hey, why did Gloria get seven and everyone else got three?” “No, I don’t know, but tell her not to get seven. It’s too much. Three sets are enough”. … After that, people with symptoms came and [Sergio] said, “I recommend you this [Gloria’s now-modified treatment], because it’s … what they’re recommending.”¹³²

Figure 3. A freshly used syringe and the packaging of a ceftriaxone vial on Gloria’s table. Digital photo by RRG, La Merced market in Mexico City, February 24, 2024.

Gloria explained this practice by saying that “If one of us had gone to the doctor it meant others didn’t have to pay”—echoing Marcelo’s suggestion that dispensing antibiotics without a prescription helps customers reduce their health expenditures.¹³³ Gloria furthermore justified Sergio’s reliance on Marcelo’s expertise by attributing to him some form of training—notwithstanding knowing him personally from his earlier time in the market and despite Marcelo’s own forthrightness about his education.¹³⁴ Meanwhile, the ‘average prescriptions’ Sergio had encountered and Marcelo’s advice—had created something like a standard antibiotic treatment for customers of the medicine-and-potato stall, closely echoing the process Rodrigues described: that a “standardisation of prescriptions” became “[…] a source of knowledge in self-medication practices” among patients.¹³⁵ In Sergio’s case, standardized prescriptions had become a source of knowledge for his IMS prescribing practices.

However, Sergio did not simply reproduce prescriptions. He adjusted them to fit previously encountered treatments and his notions of safety, another practice consistent with Rodrigues’ findings of patient-led prescription modification.¹³⁶ Yet another important reason behind Sergio’s “tinkering” with prescriptions was promoting access to medical healthcare in La Merced, even if indirectly.¹³⁷

According to Mexican pharmacy standards, prescriptions are supposed to be individual and personalized, and the rational drug use framework mandates that they must be followed to the doctor’s letter. ¹³⁸ In contrast, in La Merced, Sergio “localized” antibiotic prescriptions in two ways.¹³⁹ Firstly, by measuring them against others he had encountered and coming to an almost mathematically average treatment—not seven, but three to five ceftriaxones.¹⁴⁰ Secondly, by reusing that average to recommend treatments to other patients with similar symptoms (e.g., green phlegm and/or throat-and-body pain).¹⁴¹ Thus, Sergio ‘averaged’ antibiotic prescriptions and then collectivized them—practically making his ‘patients,’ with Gloria’s help, share medical consultations.¹⁴²

These practices and locals’ self-prescription placed ceftriaxone and amoxicillin among Sergio’s best-sellers (see Figure 4).¹⁴³ During fieldwork, RRG only once saw a customer with a prescription in Sergio’s stall. It was not for antibiotics. Nonetheless, Sergio continuously delivered ceftriaxone ampules, and pairs of Terramicina pills (oxytetracycline) across the market.¹⁴⁴ Some were customary deliveries, but others were Sergio’s “practical tinkering” to comply with a version of Marcelo’s version of antibiotic control.¹⁴⁵

Figure 4. The antibiotics section of the medicine-and-potato stall. The second and third levels from the top down are mostly filled with ceftriaxone ampules. Digital photo by RRG, La Merced market in Mexico City, April 12, 2024.

5.2. Delivering antibiotic treatment adherence

To mitigate the risk of “bacterial resistance,” the AMR-related term usually printed on antibiotic packaging warnings in Mexico, Sergio often took the precaution of making his customers finish their treatments.¹⁴⁶ He picked up this policy from Marcelo’s time in the market.

I’ve known for a long time that antibiotic treatments must be completed. … I’ve had it in mind, that they’re finished according to the prescription or my cousin’s suggestion, who sold them here [in the market]. … I’ve seen it myself. I’ve felt ill regarding bacteria and by the second or third doses I generally felt better. … But … I know that the treatment must be completed because if you don’t then it can bounce back or generate … bacterial resistance. So then, I have always emphasized to my patients who come get antibiotics that “treatment is for seven days or five days.” Injections, we work with a minimum of three doses … four or five would be ideal. … So we kill the bacteria the most we can.¹⁴⁷

Enacting Marcelo’s version of antibiotic control, however, was more challenging in La Merced than in Marcelo’s pharmacies. For Marcelo, his “contested” version consisted of warning his customers about the risks of not finishing their treatments.¹⁴⁸ For Sergio, enacting antibiotic control meant delivering doses of antibiotics across the market. Sergio tracked people down so they did not forget their antibiotic doses—either prescribed by a doctor or in the potato-and-medicine stall.¹⁴⁹ An important reason behind this practice was that customers in La Merced often did not buy what Sergio considered ‘complete’ treatments—for example, with ceftriaxone injections:

Normally they come and they just buy one. … When I know they’re [supposed to be] from three to five [doses]. I tell them to take the rest. They say they don’t have money. … If I know them, I tell them to take them, and they can pay me the next day. The goal is that they get the complete treatment. Because I’m left feeling remorse or the responsibility of saying, “these guys maybe … forget”, but I can’t disregard the situation as easily as they can. … If I don’t know them, I ask them where they sell [in the market] and I go see them. … The next day, I know they need their treatment and I’m worried and I sometimes look for them in their business. … I sometimes think I don’t take as good care of myself as I do them. But maybe, because of ignorance, they feel better from one or two antibiotic injections, and they might think the rest is because I want to sell. … But I’ve explained to them “It’s fine by me if you don’t take it, it’s not to sell you another antibiotic, but for yourself, so we don’t create a resistant bacterium”. Most of them understand.¹⁵⁰

Sergio cared very deeply about not letting his customers purchase or consume single doses of ceftriaxone, yet often had to accommodate their financial constraints. Specifically, the money his customers carried in their pockets when visiting his stall.¹⁵¹ Many merchants in La Merced start the day off bringing to the market just enough money to give customers their change. Muggings are common in the area, especially for merchants, who are known to carry cash. Over the course of the day, they earn what they need to eat and pay their suppliers. Perhaps the most important reason behind single-dose purchasing is that many merchants scrape by with what they make every day, with very small profit margins.¹⁵²

This is why RRG often saw Sergio track people down to give them their doses, customers who were not always interested in continuing the treatment.

When I got to the market Gloria asked me to tell Sergio she had injected his customer, a woman who sells chicken soup. Around 4 pm, a little before the workday was over, Sergio said he had to go deliver medicine. I stayed in the “pharmacy” and when he came back, a few minutes later, he put a little box of ceftriaxone on the potato table. Since I was helping him set up the medicines on the shelves, I asked if the ceftriaxone box should be placed there too. He said it didn’t. He then told me the chicken soup seller had gotten angry because the first ceftriaxone dose had not had any effect. She had rejected the second dose, now just sitting beside the potatoes. The patient said she would best go to the doctor. Sergio said he did not like getting involved with patients after they had that sort of attitudes. He seemed distraught.¹⁵³

Sergio tracked his ‘patients’ down, let them borrow the medicines and pay later, and like that day, worried when he deemed the local ‘average’ antibiotic treatment was interrupted.¹⁵⁴ Thus, Sergio’s “practical tinkering” adjusted his practice, albeit less to official antibiotic control standards than to Marcelo’s “contested” version of antibiotic control.¹⁵⁵ A version in which it is “actually super good” to “indiscriminately” dispense antibiotics, so long as the seller takes measures to make customers complete their treatments.¹⁵⁶ Marcelo warned customers about the potential risks involved, while Sergio let them borrow antibiotics and chased them through the market with their subsequent doses.

Sergio recognized the “motivational ambivalence” of his practices, which could be interpreted as antibiotic pushing. ¹⁵⁷ However, his report that acknowledging this ambivalence to his customers legitimized his antibiotic control practices suggests a degree of reflexivity on both sides of the transaction. This level of awareness would likely serve as a check on suspected profiteering. Indeed, it is reasonable to suppose that taking advantage of Sergio’s clientele—largely composed of experienced, multigenerational merchants—would not be easy, even when dealing in antibiotics.

A local doctor reflecting on Sergio’s prescription modifications and customer “chasing,” would later suggest that, at least in theory, he might have been preventing AMR.¹⁵⁸ This “functional ambivalence,” with optimization on one side and misuse on the other, hinged (at least) on Sergio and his customers completing treatments that matched the correct diagnosis, bug–drug combination, and dosage—a challenging proposition.¹⁵⁹ Evaluating Sergio’s practices becomes even more complex in light of ongoing debates surrounding the link between antibiotic treatment interruption and the development of resistance.¹⁶⁰ However, in the absence of formal oversight, Sergio’s antibiotic control reflected the ambivalent and “informal regulation” necessitated by La Merced’s healthcare itineraries—constrained by time, money and access.¹⁶¹

6. Streetsmarts and care within ambivalence

Throughout this paper, we traced how two IMSs contested, adjusted, and reassembled antibiotic control standards in marginalized urban pharmaceutical outlets. Marcelo challenged antibiotic accounting standards as corruptly implemented; the prescription requirement as imposing unaffordable medical obligations on impoverished consumers; and the medical authority inscribed in prescriptions as excluding his clientele from access to effective antibiotics. In La Merced, Sergio and Gloria implicitly contested prescriptions themselves, which individualized and restricted an expensive resource that, in their view, can be shared: medical care. From the perspective of the IMSs we shadowed, these rationales legitimized their informal practices. They also manifested the latent normative, functional, and motivational ambivalence of their work, the latter often addressed through phrases echoing the sentiment that it’s not about the money. Yet, without exception, these rationales also aligned neatly with their economic interests. However, IMSs did not simply bypass standards and justify themselves. Marcelo emphasized communicating to customers that they had to finish their treatments, while Sergio delivered antibiotic doses to make sure they did—adapting antibiotic control to their businesses and communities.

These versions of antibiotic control have intertwined theoretical and policy implications. They show that informality can be studied as a localized, pragmatically reassembled version of formality, and, consequently, that such tinkering contains adjustments that may help better communicate and address AMR concerns at the street-level. Examples include telling customers that bacteria “vaccinate themselves” with antibiotics or creating guidelines to orient medicine sellers serving populations who can afford only single doses at a time. At the same time, IMSs’ tinkering responds to systemic failure—it does not resolve it.

The rationales and practices we presented highlight that antibiotic regulations can codify scientific knowledge into explanations, stakes, and responses to AMR, while embedding assumptions about the roles each member of the “… antibiotic care network[]” is willing and able to play.¹⁶² However, unlike the science they partially draw on, these standards are seldom treated as open to ongoing debate. In Mexico, when they are modified, it is usually unilaterally, by a committee of experts. Yet, the distance between regulatory texts and street-level reality suggests that these experts lack (or sideline) streetsmarts: the knowledge developed in situations of marginality, where risk, regulation, corruption, poverty, and lay expertise converge.

While IMS tinkering produces situated forms of antibiotic control, it cannot reliably mitigate the risks created by weak official regulation and structural barriers to quality healthcare. In the case of AMR, particularly when treatment begins without diagnosis or prescription, tinkering cannot compensate for widespread inappropriate antibiotic dispensing, nor can any rationale justify the risks it entails. Informal adjustments may ease some consequences of inequality, but they cannot substitute access to doctors, prescriptions, functional health systems, and reliable oversight. As Rodrigues argues: “… individuals’ rationales should not be seen as part of the problem, but should rather be incorporated into the solution.”¹⁶³ The same goes for their tinkering. Designing effective and just antibiotic regulations requires incorporating street-level expertise and ingenuity—without treating them as a panacea for structural exclusion.

Our ethnographic immersion restricted us to shadowing a small number of IMSs, limiting generalizability. However, the ubiquity of the types of establishments our interlocutors worked in suggests that their concerns and practices likely echo those of other IMSs in Mexico City, especially in marginalized neighborhoods. Our findings also carry broader implications for research on IMSs globally.

We stress that scholarship on IMSs must recognize their capacity to reflect on their dual role and sustain care within ambivalence. This is not a call to romanticize IMSs, but to shift attention from their double incentives—however analytically intriguing—to the practical value and potential of their work in context. Treating their justifications for rule-bending as fully formed rationales is essential to understanding the systemic failures that give them rhetorical and ethical force. Corruption and inadequate healthcare make a good case for breaking the rules, and the profitability of IMS care should not discount their accounts of the real problems their informal practices address. Breaking the rules may stem from economic self-interest but remaking them from the bottom up takes real care.