Pharmaceutical Supply Chain Inefficiencies and Medication Affordability in Resource-Constrained Health Systems: A Narrative Review

prices and decomposed into the add-on costs accumulated at each stage of the chain (World Health Organization & Health Action International, 2008). Where this review cites availability percentages, price ratios, or component breakdowns, those figures derive from this or compatible methods, which lends them a degree of cross-country comparability that ad hoc price reports lack. Affordability in this tradition is conventionally expressed as the number of days' wages a lowest-paid unskilled government worker must spend to purchase a standard course of IJHPR treatment, a metric that makes cross-country comparison possible and exposes how even nominally modest unit prices can be prohibitive relative to local incomes (Niens et al., 2012; Wigley et al., 2020). Because the literature spans pharmacy practice, health economics, operations and supply chain management, and global health policy, the synthesis is deliberately cross-disciplinary. The review does not assign formal quality scores to individual studies and does not pool effect estimates; its contribution is structural and integrative. Where findings conflict or where the evidence is limited to particular disease areas or regions, this is noted rather than smoothed over. This review was conducted and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement (Page et al., 2021). PubMed/MEDLINE, Scopus, Embase, and Web of Science were searched, together with Google Scholar and the reference lists of retrieved articles, for records published up to 2023, using search terms combining medicine prices, affordability, and pharmaceutical supply-chain performance. Records were collated and de-duplicated; titles and abstracts were screened against predefined eligibility criteria, and the full texts of potentially eligible reports were assessed. Studies were eligible if they addressed the review question and reported relevant empirical findings, methodological comparisons, or authoritative guidance, with key reviews and seminal works retained where they informed the synthesis; records were excluded if they did not address the question, lacked extractable data, or were editorials or other non-peer-reviewed material. The identification, screening, and selection process is summarized in Figure 2, and 105 sources met the criteria and were included. Given the methodological heterogeneity of the evidence, findings are synthesized narratively rather than through quantitative meta-analysis. IJHPR Figure 2. PRISMA 2020 flow diagram of study identification and selection. 2. The pharmaceutical value chain and the structure of cost 2.1 The pharmaceutical value chain in resource-constrained settings The pharmaceutical supply chain is a sequence of linked stages, each of which can add cost or introduce the risk of interruption. In simplified form it runs from product selection and quantification, through procurement and financing, into importation and customs clearance, then to central and intermediate warehousing, onward distribution to facilities, and finally to dispensing at the point of care. In high-income settings, much of this chain is operated by specialized private logistics firms with mature information systems. In many lower-income settings the public sector itself carries a far larger share of distribution, often through government-owned central medical stores and fleets, while operating with a narrower tax base, weaker management autonomy, and thinner technical capacity (Institute of Medicine, 2013; Lydon et al., 2015; Yadav, 2015). IJHPR Two features of medicines make the chain unusually unforgiving. First, many products are perishable or temperature-sensitive, so failures in storage and transport do not merely delay supply but can destroy it. Second, the consequences of failure are borne in health rather than in inventory write-offs alone: a stockout of a first-line antimalarial or an antihypertensive is not a deferred sale but an untreated illness. These features mean that inefficiencies which would be tolerable in a consumer supply chain become, in the pharmaceutical context, direct determinants of morbidity and financial hardship. A third feature compounds the first two: the chain is long, multi-tiered, and frequently fragmented across public and private actors whose incentives are not aligned. Each handoff between a manufacturer, an importer, a wholesaler, a distributor, a central store, a regional depot, and a dispensing outlet is an opportunity for cost to be added and for accountability to be lost. The same fragmentation that raises price also obscures it, because no single actor sees the full build-up of margins from factory gate to patient. Diagnostic frameworks for health-product supply chains in developing countries have therefore emphasized that underperformance is rarely the fault of a single stage; it is a systemic property of how the stages are organized and connected (Yadav, 2015). This systemic character is the reason that point solutions so often disappoint, a theme that recurs throughout this review. The coexistence of parallel public and private channels deserves particular attention, because it shapes both price and equity. In many settings the public sector procures centrally and supplies facilities at or near cost but is chronically stocked out, while a parallel private sector is reliably stocked but prices at a substantial multiple of the public benchmark. Patients move between the two not by preference but by necessity, defaulting to the private channel whenever the public shelf is empty, so that the public sector's stockouts are effectively converted into private-sector spending by the household (Cameron et al., 2009). This dynamic means that public availability and private price are not independent: improving public-sector reliability does not merely fill a gap, it removes the coercion that pushes patients toward the higher-priced channel in the first place. Any assessment of affordability that examines one channel in isolation will therefore misjudge the burden, because the true cost to the patient is determined by the interaction between an unreliable low-price channel and a reliable high-price one (Cameron et al., 2009). Systematic review evidence confirms both the extent of public-sector stockouts, including at the community level where frontline health workers are frequently out of essential commodities, and the hazard of assuming that the better-stocked private channel is necessarily the higher-quality one, since comparative studies of public and private ambulatory care in these settings find quality deficiencies on both sides of the divide (Berendes et al., 2011; Olaniran et al., 2022). The private channel is not monolithic, moreover: in many low-income settings it includes a large semi-formal and informal retail tier of drug shops and medicine sellers that serves as the first point of care for the rural poor, valued for proximity, shorter waits, and flexible payment, but characterized by uneven dispensing practice, frequent sale of incomplete courses, and variable product quality; accreditation and training programs for these outlets have been shown to improve the quality of products and services where they are sustained (Goodman et al., 2007; Wafula et al., 2012). Studies of patent medicine vendors and their customers, together with systematic reviews of interventions targeting informal private providers, reinforce both points: such vendors are deeply embedded in care- seeking, particularly in rural areas, yet durably improving their dispensing practice has proven difficult and tends to require sustained training, supervision, and regulation rather than one-off measures (Brieger et al., 2004; Embrey et al., 2016; Haines et al., 2007; Lewin et al., 2010; Shah et al., 2011). IJHPR A structural feature upstream of all these channels is the heavy dependence of many low-income regions on imported finished products. In sub-Saharan Africa, a large majority of the medicines consumed are imported, and local production is increasingly promoted as a way to shorten supply lines, improve the timeliness and predictability of availability, and reduce exposure to substandard and falsified imports. The evidence is cautiously supportive but conditional. Analysis of tracer- medicine data from one African market found that locally produced medicines were distributed as evenly between rural and urban areas as imported ones, suggesting a distributional benefit, while policy analyses emphasize that the access and quality gains from local production are realized only where regulatory capacity, Good Manufacturing Practice enforcement, and post-market surveillance are strong enough to ensure that domestically made products are themselves quality- assured (Fatokun, 2020; Mujinja et al., 2014). Local production is therefore not a substitute for the procurement, distribution, and regulatory reforms examined in this review, but a complementary structural option whose benefits depend on the same system foundations (Aminu-Ibrahim et al., 2020). 2.2 Upstream inefficiencies: procurement fragmentation and weak forecasting The earliest stages of the chain set the terms for everything that follows. Quantification, the process of estimating how much of each product will be needed, is frequently undermined by incomplete consumption data, unreliable facility reporting, and limited forecasting capacity. When forecasts are inaccurate, the system swings between two costly failure modes: understocking, which produces the stockouts that drive patients to higher-priced private alternatives, and overstocking, which ties up scarce funds and generates wastage as products expire. The pandemic period made these dynamics vivid, as panic buying, self-medication, and unpredictable demand overwhelmed forecasting systems and produced simultaneous shortages and overstock across different product categories (Yaroson et al., 2019). Shortages are not solely a forecasting failure; commentaries synthesizing experience across income levels attribute them to causes spanning raw-material availability, manufacturing capacity and quality problems, industry consolidation, marketing practices, and procurement and supply chain management, and note that whatever the proximate cause, shortages raise system costs as providers scramble for substitutes (Iyengar et al., 2016). Practitioner syntheses of global health supply chains rank inaccurate forecasting and poor data quality among the most consequential and persistent problems in the field, and structured quantification methods exist precisely to convert imperfect consumption records into defensible procurement estimates; where a formal demand-forecasting system has been introduced into a low- income country's supply chain, modeling indicates measurable reductions in both stockouts and wastage (Mueller et al., 2016; Privett & Gonsalvez, 2014; USAID DELIVER Project, 2014). Procurement is the second upstream weak point. Fragmented purchasing, in which many small buyers each contract independently, forfeits the bargaining power that volume confers and leaves low-volume purchasers exposed to concentrated supplier markets. Ineffective procurement systems have been documented as a direct barrier to the availability of essential medicines across large multi-country samples; an analysis of asthma medicines spanning 52 low- and middle- income countries, for example, linked weak procurement to poor availability of basic respiratory treatments (Babar et al., 2013). A systematic review of supply chain and procurement interventions concluded that the root causes of underperformance lie substantially in how purchasing and delivery are organized, and that centralizing procurement can yield cost savings across many contexts while improvements in supply chain management can reduce stockouts (Seidman & Atun, 2017). The procurement process itself is often part of the problem: the common practice of floating IJHPR short-term tenders several times a year lengthens lead times and contributes to stockouts, whereas flexible, pre-established framework agreements, long-term contracts that fix terms while permitting smaller repeat orders, have been shown to shorten lead times, reduce stockouts, and improve commodity security, provided enabling legislation and contract-management capacity are in place; structured guidance on framework agreements and electronic reverse auctions now exists to support such reforms (Arney et al., 2014; World Bank, 2021). Financing compounds the problem: where procurement budgets are unpredictable or released late, purchasing efficiency collapses regardless of how well contracts are designed (Rowe et al., 2018). The quality of procurement also determines what enters the chain in the first place. Purchasing that selects on lowest nominal price without adequate supplier prequalification, quality assurance, and post-delivery testing can admit products that are cheaper precisely because they are substandard, shifting cost from the procurement ledger to the patient's health. Conversely, procurement that bundles quality assurance with volume aggregation can lower price and raise quality simultaneously. The upstream stages, in short, are not merely a cost center to be minimized; they are the point at which price, quality, and reliability are jointly determined, and weakness here propagates through every subsequent stage. 2.3 Distribution and the last mile Once procured, medicines must be moved, often across long distances and difficult terrain, to the facilities where patients present. The distribution function is where many resource-constrained systems lose the most ground, because it combines high fixed costs, fragmented demand, and weak transport infrastructure. Where distribution is organized as a long chain of intermediaries, each adding a margin and each introducing a handoff at which product can be delayed, damaged, or diverted, the cumulative effect is both higher cost and lower reliability. Cost-minimization analysis of alternative storage and distribution arrangements, comparing how stock is held and moved between immunization and central medical-store channels in one national system, illustrates that distribution design choices carry measurable and avoidable cost differences that compound across the network (Bulula et al., 2020). Distribution structure itself drives both cost and reliability. A large randomized experiment in Zambia compared a conventional multi-tier public distribution system with a more direct arrangement in which facilities ordered and received medicines from a central agency through a cross-docking model. The direct structure substantially reduced both the frequency and duration of stockouts; for first-line pediatric malaria medicines, the frequency of stockouts fell from roughly 48 percent to 13 percent and the number of stockout days in a quarter fell from about 27 to 5 (Vledder et al., 2019). The lesson is that distribution design is not a neutral logistics detail but a primary determinant of whether medicines are present when patients arrive. The last mile, the final segment that connects a distribution hub to a remote facility or community, is disproportionately expensive and disproportionately fragile. It is here that the economics of the chain are least favorable: volumes are small, journeys are long, roads are poor, and the cost per unit delivered is highest. It is also here that failures are most consequential for equity, because the patients served by the last mile are typically the poorest and most remote, with the fewest private alternatives when supply fails. Resilience analyses of pharmaceutical supply chains have emphasized that agility, the capacity to reconfigure routing and replenishment quickly in response to disruption, is central to keeping the last mile supplied when shocks occur (Yaroson et al., 2019). The recurring finding across distribution studies is that the structure of the network, not merely the effort expended within it, governs whether medicines reach the end of the line. IJHPR Resilience to shocks has moved from a peripheral concern to a central one. The pandemic period functioned as a system-wide stress test, exposing how quickly distribution can fail when demand spikes, borders close, freight capacity contracts, and a single overseas source of an active ingredient is disrupted. Forecasting systems built for stable demand swung between shortage and overstock, and chains with little buffering or routing flexibility transmitted upstream disruption directly to the facility shelf (Yaroson et al., 2019). The episode clarified that efficiency and resilience are not the same property and can even pull against each other: a chain optimized to hold minimal inventory and rely on a single supplier is cheap in calm conditions and brittle in turbulent ones. The resilience literature therefore argues for deliberately engineered slack, including diversified sourcing, strategic buffer stocks for critical products, and the agility to re-route supply, accepting a modest standing cost in exchange for protection against the far larger cost of a stockout during a shock (Yaroson et al., 2019). For resource-constrained systems with thin margins and limited reserves, building this resilience is harder and the case for regional pooling and cooperation, which spreads both purchasing power and risk, is correspondingly stronger (Bigdeli et al., 2013; Kok et al., 2022). 2.4 The anatomy of the patient price To understand why supply chain inefficiency raises cost, it is necessary to look inside the price a patient pays. The standardized price-component method tracks a medicine from the manufacturer's selling price through each successive add-on: international freight and insurance, importation and clearing charges, wholesale mark-up, retail or dispensing mark-up, and any taxes, tariffs, or regulatory fees applied along the way (World Health Organization & Health Action International, 2008). Surveys using this method have repeatedly found that the manufacturer's selling price is only a fraction of the final retail price, and that the remainder is built from the cumulative margins and charges added downstream. In some markets the add-on costs more than double the price between factory gate and patient, and mark-ups and taxes together can constitute a substantial share of what the patient ultimately pays (World Health Organization & Health Action International, 2008). The multi-country pricing evidence makes the same point from a different angle. Across 36 low- and middle-income countries, patient prices for lowest-priced generic medicines in the private sector averaged several times the international reference price, and originator-brand products cost far more again, while public-sector procurement prices were much closer to the reference benchmark (Cameron et al., 2009). The gap between what governments pay at procurement and what patients pay at retail is precisely the space into which distribution margins, taxes, and inefficiency are inserted. When that gap is large, it signals that the surplus is being added downstream of procurement, in the distribution and dispensing stages, rather than originating in the intrinsic cost of the product (Valimba et al., 2014). The scale of the gap between reference prices and patient prices has been quantified repeatedly. The landmark multi-country analysis found that patients frequently paid on the order of 9 to 25 times the international reference price for the lowest-priced generic in the private sector, and substantially more again for originator-brand products, while availability of generics across regions ranged only from about 29 percent to 54 percent (Cameron et al., 2009). A more recent secondary analysis covering 54 low- and middle-income countries reaffirmed both findings, reporting persistently high price ratios for lowest-priced generics and originator brands and availability in the same low range, and noting that the intervening years of economic change and technological advance had not closed the gap. The same body of work shows that one month of IJHPR treatment for common chronic noncommunicable conditions remains unaffordable for a large share of the population when purchased privately, which is precisely the segment of demand most exposed to supply chain inefficiency. A multi-country survey of medicines for cardiovascular disease, diabetes, chronic respiratory disease, and other chronic conditions across six low- and middle-income countries reached the same conclusion, finding these essential treatments frequently unaffordable in the private sector and identifying tax exemption, mark-up regulation, and generic promotion among the measures associated with lower prices (Dimitrova et al., 2023; Mendis et al., 2007). 2.5 Generic competition and reference pricing as price levers If the patient price is built largely from downstream margins applied to a product whose underlying cost is modest, then the most direct route to lower prices is robust competition among quality- assured generic versions. The experience of generic-medicine policy bears this out. Reviews of generic policy across multiple countries report that when a sufficient number of generic competitors enter a market, average prices fall steeply, in some cases to a small fraction of the originator price, and that mandatory generic-substitution policies have produced overall price reductions on the order of 15 percent, with far larger reductions, exceeding 40 percent, for off- patent molecules over a few years (Hassali et al., 2014). Empirical analyses of generic markets quantify this relationship directly: each additional supplier tends to lower price, with the steepest declines emerging once several manufacturers compete, so that a market with a single generic entrant shows only a modest reduction while markets reaching six or more competitors approach the marginal cost of production (Frank & Salkever, 1997; Reiffen & Ward, 2005; U.S. Food and Drug Administration, 2019). While the most rigorous of these evaluations come from higher- income systems, the mechanism, competition among interchangeable products combined with policies that direct demand toward the lowest-priced quality-assured option, is general and is widely recommended for lower-income settings (Hassali et al., 2014). Pricing policy provides the instruments to capture these gains where competition alone is insufficient. Frameworks developed for low- and middle-income contexts emphasize a small set of complementary tools: external reference pricing, in which a country benchmarks its prices against those in comparator countries; internal reference pricing, including the generic price link that sets a generic's price as a defined percentage below the originator; and tiered pricing structures that lower prices as additional generics enter the market. These instruments work best in combination with transparency measures such as centralized price databases and regular price reviews, which reduce the information asymmetry that allows margins to expand unobserved. The recurring caveat in this literature mirrors the caveat for pooled procurement: pricing policy depends on enabling conditions, including early generic market entry, prescriber and consumer acceptance of generics, and the quality assurance without which substitution simply trades a high- priced effective product for a cheap ineffective one (Hassali et al., 2014). For products still under patent, the instruments differ again: intellectual-property flexibilities recognized in international trade law, including compulsory and voluntary licensing, have been invoked by a range of countries to enable lower-cost supply of patented medicines, although their practical leverage depends on local manufacturing capacity and negotiating position rather than on the legal provision alone ('t Hoen et al., 2011). Voluntary licensing arranged through public-health intermediaries offers a complementary route, and documented experience with negotiating such agreements shows that they can expand access to newer health technologies where the terms are structured to permit competitive generic supply (Gore et al., 2023). IJHPR Generic policy and supply chain efficiency are mutually reinforcing rather than separate agendas. Generic competition lowers the manufacturer's selling price at the top of the chain; supply chain efficiency and mark-up regulation prevent that saving from being absorbed by downstream margins before it reaches the patient; and quality assurance ensures that the cheaper product is genuinely equivalent. A reform that lowers the ex-factory price but leaves a long, high-margin distribution chain intact will deliver only a fraction of its potential benefit to the patient, which is why the price-component perspective and the generic-competition perspective belong in the same analysis (Cameron et al., 2009; World Health Organization & Health Action International, 2008). 2.6 Storage, cold chain, and regulatory delay Storage and transport conditions are a further source of loss. Many essential products, including vaccines, insulin, and a range of biologicals, require maintenance of a controlled temperature from manufacture to administration. Where electricity supply is irregular, refrigeration unreliable, and warehousing capacity limited, the cold chain is repeatedly broken, degrading product quality and forcing wastage even when nominal supply is adequate. Field observations have linked unreliable power and inadequate temperature control to compromised cold chains for medicines and vaccines, and have identified weak infrastructure as a recurring constraint on availability, particularly outside major urban centers (Ozawa et al., 2018). Poor storage and handling also create entry points for product degradation that are independent of manufacturing quality, so that medicines made to standard can still reach the patient in a substandard state (Institute of Medicine, 2013). The cold chain is among the oldest and most studied components of the immunization supply system, and its extension to an ever-wider range of temperature-sensitive products has made systematic temperature-excursion management a core quality function rather than a peripheral logistics concern, since a single uncontrolled excursion can render a compliant product subpotent before it is ever dispensed (Haidari et al., 2016; Kumar & Jha, 2017; Lloyd & Cheyne, 2017; Prosser et al., 2017). Regulatory and importation processes add time and cost at the border and at the point of market authorization. Slow customs clearance, complex import licensing, and limited national regulatory capacity lengthen lead times and raise the cost of holding inventory, while opaque and fragmented oversight creates openings through which poor-quality products enter the legitimate chain. Reviews of medicines quality in lower-income markets have identified inadequate regulatory infrastructure, inconsistent enforcement, resource scarcity, and opaque supply chains among the principal reasons that substandard products are not detected and removed (World Health Organization, 2017). An analytic framework derived from qualitative research across several middle-income markets has characterized more precisely how particular market conditions, including fragmented and opaque distribution, weak buyer power, and limited regulatory reach, create the openings through which substandard and falsified products enter the legitimate chain, which helps explain why purely technical detection measures underperform when the underlying market structure is left unchanged (Pisani et al., 2019). Regulatory weakness, in other words, is not only a safety concern; it is a supply chain inefficiency that simultaneously raises cost and admits harmful products (Yadav et al., 2014). The time dimension of regulation deserves particular emphasis because its costs are easy to overlook. Every additional week that a consignment spends awaiting clearance or authorization is a week of inventory holding cost, a week of shelf life consumed, and a week closer to the expiry that turns a purchased asset into wastage. Long and unpredictable lead times also force the system to hold larger safety stocks to buffer against delay, which ties up working capital and increases the volume exposed to cold-chain and storage risk. Thus regulatory delay does not merely postpone IJHPR access; it raises the steady-state cost of running the chain and amplifies the wastage and stockout dynamics described in the upstream stages (Institute of Medicine, 2013; Yadav, 2015). 3. From inefficiency to affordability and its consequences 3.1 From inefficiency to affordability and out-of-pocket burden The cumulative effect of these inefficiencies is felt by patients as price. In many resource- constrained settings, medicines account for a large share of total health expenditure, and the great majority of that spending is paid out of pocket at the point of purchase rather than through pooled or prepaid financing (Cameron et al., 2009; Wirtz et al., 2017). This combination, high medicine costs and direct payment, transmits every upstream inefficiency to the household. When public- sector availability is low, patients buy in the private sector at multiples of the reference price; when distribution is fragmented, they pay the compounded mark-ups; when forecasting fails, they pay the premium that scarcity commands. Set against a global medicine market valued in the trillions of dollars, access in many lower-income countries has nonetheless been characterized as flat or declining in recent years, a divergence that underscores how aggregate market growth fails to translate into access where financing is fragmented and payment is out of pocket (Folz, 2018; IQVIA Institute, 2021; IQVIA Institute for Human Data Science, 2021; Tougher et al., 2012). Where these payments are large relative to household resources, they become catastrophic, consuming income that would otherwise meet basic needs and pushing families toward impoverishment. Out-of-pocket payments for medicines are a recognized driver of catastrophic health expenditure, and the burden falls disproportionately on low-income groups and on those managing chronic non-communicable conditions, including cardiovascular disease, that require sustained, repeated purchasing, a burden documented in sub-Saharan African settings (Bigdeli et al., 2013; Okwah, 2022). Affordability, on this view, is not a property of a medicine in isolation but an emergent outcome of the entire chain that delivers it: the same tablet can be affordable or ruinous depending on how efficiently the system that supplied it was run. The concept of catastrophic health expenditure gives this burden a measurable form. It is commonly defined as out-of-pocket spending that exceeds a set share, often 10 percent or 25 percent, of a household's total consumption, a threshold above which the payment is presumed to displace other essential needs (Wagstaff & van Doorslaer, 2003). By this measure the problem is large and has not been shrinking. Global tracking across 133 countries estimated that the incidence of catastrophic spending at the 10 percent threshold rose from about 9.7 percent of the world's population in 2000 to 11.4 percent in 2005 and 11.7 percent in 2010, even as the average share of health spending paid out of pocket fell in some regions (Wagstaff et al., 2018). The persistence and growth of catastrophic spending, despite nominal progress on coverage, indicates that the financial-protection failure is structural rather than incidental, and medicines, as the largest single component of out-of-pocket spending in many settings, are central to it (Cameron et al., 2009; Wirtz et al., 2017). Seen together, the pricing evidence and the financial-protection evidence describe a single transmission mechanism. Supply chain inefficiency widens the gap between procurement price and patient price; out-of-pocket financing converts that gap into direct household payment; and the absence of pooled or prepaid financing leaves the household to absorb the full shock. Each step is necessary to the harm, and each is a potential point of intervention. A reform that shortens the distribution chain reduces the price gap; a financing reform that substitutes prepayment for out-of-pocket payment reduces the household's exposure to whatever gap remains. The two are complementary, and the literature is clear that neither alone is sufficient to secure affordability (Wagstaff et al., 2018; Wirtz et al., 2017). IJHPR The household response to unaffordable prices is itself a source of lasting harm that price statistics do not fully capture. Faced with a cost that exceeds available cash, families borrow, sell assets, divert spending from food and schooling, or simply forgo treatment, and these coping strategies can entrench poverty even when the immediate bill is somehow met (Wagstaff & van Doorslaer, 2003). The measurement tradition distinguishes the incidence of catastrophic spending from its impoverishing effect precisely because a payment can be non-catastrophic by one threshold yet still push a near-poor household below the poverty line (Wagstaff et al., 2018; Wagstaff & van Doorslaer, 2003). For chronic conditions the dynamic is especially corrosive, because the cost recurs month after month, so that a single episode of unaffordability becomes a permanent drain that compounds over years and interacts with the supply-side unreliability described earlier: a patient who finally secures an affordable supply may still face a stockout the following month, and the cumulative uncertainty discourages the sustained adherence that chronic therapy requires (Cameron et al., 2009; Wagstaff et al., 2018). 3.2 Downstream consequences: non-adherence, substitution, and poor-quality products Unaffordability and unreliable supply do not simply leave demand unmet; they reshape patient behavior in ways that worsen outcomes and, paradoxically, raise total costs. The first consequence is non-adherence. When patients cannot afford a full course or a continuous chronic regimen, they delay filling prescriptions, skip doses, split tablets, or abandon treatment, and these cost-driven behaviors are most common among the lowest-income patients (Hafner et al., 2017). Non- adherence undermines the clinical benefit of treatment and frequently leads to disease progression and avoidable acute care, so the apparent saving at the pharmacy counter is offset by larger downstream expenditure. International evidence synthesized by the World Health Organization established adherence to long-term therapies as a problem of the first order, with adherence to chronic treatment averaging only about half in many settings and considerably lower where medicines must be paid for out of pocket, and concluded that improving adherence may do more for population health than any single advance in treatment itself, which makes any supply- or price- driven interruption of continuity a direct loss of attainable health gain (Sabate, 2003). The second consequence is substitution. Faced with an unavailable or unaffordable product, patients and prescribers shift to alternatives that may be less appropriate, including switching between generic and brand products on the basis of price rather than clinical need, or turning to informal vendors and unlicensed outlets. Such outlets are more prevalent precisely where the formal chain fails to reach, and they are weakly supervised (Institute of Medicine, 2013). The third and most dangerous consequence is exposure to substandard and falsified products. The World Health Organization has estimated that at least one in ten medical products circulating in low- and middle-income countries is substandard or falsified, and that countries spend on the order of tens of billions of dollars each year on such products. A systematic review and meta-analysis estimated an overall prevalence of poor-quality medicines of roughly 13.6 percent in these settings, with notably higher figures for antimalarials and substantial figures for antibiotics, drawn from hundreds of studies and hundreds of thousands of samples (Ozawa et al., 2018). The harm is not only financial. Modelling commissioned alongside the World Health Organization estimates that poor-quality antimalarials and antibiotics contribute to large numbers of avoidable deaths, particularly among children in sub-Saharan Africa (Sunguya et al., 2017; Wafula & Goodman, 2010; World Health Organization, 2017; Zailani et al., 2020). Country-level analysis grounds these global figures in concrete terms. An economic assessment of substandard and falsified antimalarial medications in Nigeria estimated that poor-quality IJHPR antimalarials impose a substantial annual burden in additional illness, lost productivity, and avoidable deaths, with costs running into hundreds of millions of dollars and a meaningful share of under-five mortality attributable to treatment with ineffective products (Beargie et al., 2019). The Nigerian case illustrates the general mechanism: weak and inefficient supply chains create the vacuum that poor-quality products fill, because where the legitimate chain cannot deliver affordable, quality-assured medicines reliably, demand migrates to channels where quality cannot be guaranteed (Institute of Medicine, 2013). Supply chain strengthening and quality assurance are therefore not separate agendas; a reliable, affordable formal chain is itself the most effective barrier to the substandard and falsified trade. The damage from poor-quality products extends beyond the individual patient in two ways that compound the case for supply chain reform. First, subtherapeutic doses of antimicrobials, whether the result of falsification or of degradation in a broken cold chain, expose pathogens to drug levels that select for resistance without eliminating infection, contributing to the broader threat of antimicrobial resistance that undermines treatment effectiveness for entire populations (Institute of Medicine, 2013). The scale of that threat is now well quantified: a comprehensive global analysis estimated that bacterial antimicrobial resistance was associated with roughly 4.95 million deaths and directly attributable to about 1.27 million deaths in a single year, with the heaviest burden falling on western sub-Saharan Africa, the same regions where supply chain weakness and exposure to poor-quality antimicrobials are most acute (Murray et al., 2022). Second, repeated encounters with ineffective medicines erode public confidence in the health system itself, so that patients come to distrust even genuine products and may abandon formal care, an outcome that is difficult to reverse and that magnifies the original harm (Ozawa et al., 2018). These population- level externalities mean that the true cost of a weak, quality-permeable supply chain is larger than any tally of individual treatment failures, and they strengthen the argument that quality assurance must be built into procurement and distribution rather than bolted on as an afterthought. Mechanisms such as international prequalification, which assesses products against global standards of quality, safety, and efficacy so that procurers can select from a pool of quality-assured options, contribute directly to this goal by helping to displace substandard and falsified products from the legitimate procurement stream, particularly in settings with limited national regulatory capacity (Agrawal et al., 2016; Coyne, 2019; Ouma et al., 2018; Rutta et al., 2015). 4. Counter-measures, systems, and financing 4.1 Pooled procurement as a counter-measure: evidence and conditions Of the interventions proposed to counter these failures, pooled procurement is the most extensively studied, and it merits separate treatment. Pooled procurement consolidates the demand of multiple buyers into a single purchasing entity, with the aim of reducing prices through volume aggregation, improving procurement efficiency by sharing technical capacity, and stabilizing supply by making the combined market more attractive to suppliers (Kok et al., 2022). The idea is not new. The World Health Assembly noted as early as 1978 that collective purchasing could substantially reduce medicine costs, and the first inter-country mechanisms, including the Gulf Cooperation Council group purchasing arrangement and the Pan American Health Organization revolving fund, were established around that time (Kok et al., 2022). The Pan American Health Organization mechanism has now operated for more than four decades and continues to pool regional demand to secure substantial savings on vaccines and public health supplies, charging all member countries a single price regardless of order size, an arrangement that is as much an equity instrument for small buyers as a cost-reduction tool (Stephan et al., 2022). IJHPR The magnitude of the price effect can be considerable, though it varies widely with design and context. A systematic review conducted under standardized reporting guidelines, drawing on 44 empirical studies, found that pooled mechanisms reduced medicine prices by approximately 15 percent on average, with much larger reductions in specific programs (Kok et al., 2022). Sub- national volume-based procurement in China was associated with price reductions on the order of 30 percent to 46 percent across different provinces, and procurement of hepatitis C medicines through a regional pooled mechanism in Colombia was associated with a reduction of roughly 90 percent in price (Kok et al., 2022). These figures are consistent with cross-country analyses showing that centralized public procurement lowers prices, with the largest gains accruing to low- volume buyers and to products with concentrated supply (Dubois et al., 2021), and with case evidence that voluntary pooled procurement reduced the price of antiretroviral medicines (Kim & Skordis-Worrall, 2017). National volume-based procurement has also been associated with substantial reductions in patient-level medicine costs alongside modest improvements in adherence. Disease-specific and country-level studies reinforce the pattern while marking its limits: a quasi-experimental evaluation of Tanzania's pooled procurement for antimalarial commodities found improved availability and lower prices, and a comparison of centralized and decentralized procurement under Ghana's national health insurance scheme found that the centralized route generally secured lower prices, though not uniformly across all products (Mushi et al., 2020; Ofori-Ansah et al., 2019). A transactional-database analysis of antiretroviral purchasing tempers the volume narrative, however: across thousands of procurement transactions, large purchase volumes alone did not reliably lower prices, whereas third-party price negotiation and the availability of generic competition did, underscoring that aggregation works through, not instead of, a competitive supply base (Buckland-Merrett et al., 2020; Waning et al., 2009; Yadav et al., 2012). The same evidence is equally clear that pooling is not automatic in its effects. The systematic review organized the conditions for success around the three actors in any pooled mechanism. Buyers must have sufficient technical capacity, for example to forecast demand accurately, sufficient financial capacity to pay, and laws and regulations compatible with joint purchasing. The pooling organization itself must have adequate financial and technical capacity and the independence to operate without capture by any single member. Suppliers must face sufficient incentives to participate, including a market large enough to be worth serving and a payment mechanism prompt enough to be worth trusting (Kok et al., 2022). Where any of these conditions fails, the theoretical gains from aggregation do not materialize, and poorly designed pooling can even reduce supplier competition over time. The governing lesson is that the organizational structure of a pooled mechanism must be aligned with its goals and adapted to local conditions, rather than transplanted as a uniform template (Dubois et al., 2021; Kok et al., 2022). Pooled procurement therefore exemplifies the central argument of this review in miniature. It is a powerful lever that acts directly on the price-formation problem identified in the analysis of price components, and the evidence for its price effect is among the strongest in the field. But its benefit is contingent on enabling conditions, on supply-side competition, and on complementary reforms, and it cannot by itself solve a problem whose roots also lie in distribution structure, financing, and regulation. The intervention with the best evidence base is thus also a demonstration that no single intervention is sufficient. It is equally important to register the failure modes that the enthusiasm for pooling can obscure. Aggregating demand concentrates purchasing in fewer, larger contracts, which can hollow out the supplier base if smaller manufacturers are unable to compete for national or regional volumes, leaving the market more concentrated and less resilient over time. A pooled mechanism that pays IJHPR slowly or forecasts poorly can deter the very suppliers it needs, converting a theoretical price advantage into real shortages. And pooling across jurisdictions requires harmonized specifications, quality standards, and legal arrangements that are themselves demanding to construct and maintain (Kok et al., 2022). None of these cautions negates the case for pooling, but they explain why the systematic evidence stresses design and governance so heavily, and why a mechanism transplanted without attention to local supplier markets and administrative capacity can underdeliver or backfire (Dubois et al., 2021; Kok et al., 2022). The practical recommendation that emerges is to pair demand aggregation with deliberate attention to supplier sustainability, prompt payment, and quality assurance, so that lower prices do not come at the cost of a thinner or lower-quality supply base. 4.2 Information systems, demand visibility, and digitization Because the swing between stockout and overstock originates in poor demand visibility, interventions that improve consumption data, forecasting, and replenishment logic strike at a root cause of both unavailability and waste. The underlying problem is informational: when a central store cannot see what is being consumed at the periphery, it cannot replenish accurately, and the system defaults to push-based allocation that systematically mismatches supply to need. Approaches that invert this logic, including pull-based replenishment, vendor-managed inventory, and informed-push models in which trained logisticians resupply facilities on the basis of observed stock levels, are repeatedly proposed and, where evaluated, associated with reduced shortages (Seidman & Atun, 2017; Yaroson et al., 2019). Digitization is the enabling layer for these approaches. Logistics management information systems, electronic stock cards, and mobile reporting tools convert the invisible consumption at the periphery into data that can drive forecasting and replenishment. The diagnostic literature on developing-country health-product supply chains identifies weak information systems as one of the recurring root causes of underperformance, precisely because every other improvement, from procurement to distribution design, depends on accurate demand signals to function (Yadav, 2015). The pandemic period underscored both the fragility and the value of demand visibility, as systems with better information were better able to detect and respond to the simultaneous shortages and overstock that volatile demand produced (Yaroson et al., 2019). Quasi-experimental evidence puts numbers to the benefit: a pre-post and time-series evaluation across more than nine hundred facilities in three regions of Tanzania found that monthly stockout rates fell from about 7 percent to 2 percent after an integrated electronic logistics and immunization system with stock notifications replaced paper and spreadsheet reporting, with the odds of a stockout declining further the longer the system was in use (Gilbert et al., 2020). Investment in information systems is therefore not a discretionary modernization; it is a precondition for the other leverage points to deliver their potential. 4.3 Financing, prepayment, and the equity dimension Supply chain efficiency determines the cost of delivering a medicine, but financing determines who bears that cost and whether it is borne in a way that protects households from hardship. The two interact closely. A system that relies on out-of-pocket payment at the point of sale exposes every patient to the full, undiscounted consequence of any inefficiency upstream; a system that pools risk through prepayment, taxation, or insurance absorbs that consequence collectively and shields the individual household (Wagstaff et al., 2018; Wirtz et al., 2017). This is why financial- protection outcomes can differ markedly between settings with similar supply chain performance: IJHPR the same price gap produces catastrophic spending where payment is out of pocket and a manageable, pooled cost where it is prepaid. The equity dimension follows directly. Because supply chain failures concentrate at the periphery and out-of-pocket burdens concentrate among the poor, the two sources of disadvantage compound. The poorest and most remote patients are the most likely to find the public shelf empty, the most likely to face the highest private mark-ups when they turn to alternatives, and the least able to absorb the resulting payment without forgoing other necessities (Cameron et al., 2009; Wagstaff et al., 2018). A health-system perspective on access to medicines has emphasized that availability, affordability, and the financing arrangements that connect them must be addressed together, because an intervention on any one alone leaves the others to undo its gains (Bigdeli et al., 2013). The implication for policy is that supply chain reform and financing reform are not alternatives competing for the same budget; they are complementary halves of a single strategy for equitable access (Bigdeli et al., 2013; Wirtz et al., 2017). Availability and affordability are necessary but not sufficient: whether access translates into health gain also depends on appropriate use. A large body of evidence from low- and middle-income settings shows that a substantial share of prescribing and dispensing departs from standard treatment guidelines, that multifaceted interventions combining prescriber education with managerial and regulatory measures are more effective than single-strategy approaches such as the passive distribution of written guidance, and that measured progress on appropriate use across these settings has been slow and uneven over successive decades (Hogerzeil et al., 1993; Holloway et al., 2013; Laing et al., 2001). This matters for a supply chain analysis because irrational use distorts the demand signals on which quantification depends, accelerates antimicrobial resistance, and wastes the very commodities that constrained budgets have struggled to procure, so that the gains from cheaper and more reliable supply can be eroded downstream if selection and use are not addressed alongside availability and price (Holloway et al., 2013; Laing et al., 2001). Selection sits logically upstream of both price and use. The essential medicines concept, introduced by the World Health Organization in 1977 and since developed from an experience-based exercise into an evidence-based process that weighs public-health relevance, comparative efficacy, safety, and cost-effectiveness, gives health systems a rational basis for concentrating scarce procurement, financing, and distribution capacity on the products that deliver the most health per unit of spending (Hogerzeil, 2004; Laing et al., 2003). National lists derived from the model list are not merely clinical guidance; they function as a practical lever for negotiating price and securing availability, and the periodically updated model list continues to perform this standard-setting role for selection worldwide (Hogerzeil, 2004; World Health Organization, 2023). A supply chain optimized to deliver a poorly chosen basket of products cannot produce affordable access, which is why rational selection belongs within, rather than prior to, the analysis of supply chain performance. External financing adds a further layer of complexity that is particularly salient for the medicines on which poor populations most depend. Donor funding has been identified as a facilitator of access, sustaining the procurement and distribution of priority commodities that domestic budgets alone could not cover, but it also creates a transition risk: as countries grow and external support is withdrawn, the financing of those commodities must shift to domestic sources, and a supply chain built around donor logistics and donor-funded products can falter if that shift is not managed deliberately (Bigdeli et al., 2013). Sustainable access therefore depends not only on the efficiency of the chain at any moment but on the durability of its financing over time, which argues for building domestic procurement capacity, pooled financing, and supply chain institutions that can IJHPR outlast any particular funding stream (Bigdeli et al., 2013; Wirtz et al., 2017). The goal of universal health coverage makes this transition unavoidable, since financial protection cannot be secured on a financing base that is temporary or externally contingent (Wirtz et al., 2017). 5. Leverage points, reform, and discussion 5.1 Leverage points across the value chain Drawing the threads together, the literature identifies a recurring set of interventions that act on the failures described above. Four leverage points appear repeatedly and with reasonable evidentiary support, and their value lies as much in how they combine as in what each does alone. Pooled and centralized procurement As set out above, consolidating purchasing across buyers increases volume and bargaining power and is associated with lower prices in a wide range of settings, with the largest gains for low- volume buyers and concentrated-supply products, provided enabling conditions and sound governance are in place (Dubois et al., 2021; Kim & Skordis-Worrall, 2017; Kok et al., 2022). Demand-driven inventory and stronger information systems Interventions that improve consumption data, forecasting, and replenishment logic strike at the root cause of the stockout-overstock swing. Vendor-managed inventory, pull-based replenishment, and investment in supply chain information and coordination technologies are repeatedly associated with higher forecasting accuracy and reduced shortages and waste (Yadav, 2015; Yaroson et al., 2019). Concrete field implementations bear this out: an informed-push model in Senegal, in which dedicated logisticians visited facilities on a fixed schedule to count stock and replenish to defined minimums, virtually eliminated the contraceptive stockouts that had previously affected the great majority of public facilities, while also generating the consumption data needed to manage the system (Daff et al., 2014). Distribution consolidation and redesign As the Zambian experiment showed, shortening and rationalizing the distribution structure can sharply reduce stockouts without proportionate cost increases (Vledder et al., 2019). Consolidating layers, adopting cross-docking, and matching distribution design to product and demand characteristics are practical and testable levers rather than aspirational ones. Price transparency and mark-up regulation Because a large part of the patient price is built from compounded margins and taxes, measures that make prices visible and that regulate mark-ups address affordability directly. The standardized pricing evidence supports promoting quality-assured generics, regulating wholesale and retail mark-ups, removing taxes on essential medicines, and using international reference prices as benchmarks for purchasing (Cameron et al., 2009; World Health Organization & Health Action International, 2008). International guidance on national pharmaceutical pricing policy consolidates these into a recommended package, advising that generic promotion, internal and external reference pricing, mark-up regulation, and tax exemption be combined and monitored together rather than applied in isolation (World Health Organization, 2015). The empirical literature on mark-up regulation is consistent with this conditional framing: cross-country analysis of distribution remuneration and taxation policies shows that the structure of wholesale and retail margins is a major determinant of the final price built up from the ex-factory cost, and country- IJHPR level surveys confirm wide variation in applied mark-ups, with the available evidence cautiously favoring regressive over flat-percentage margins and indicating that mark-up regulation lowers prices reliably only when paired with regulation of manufacturer or retail selling prices. A consistent theme across these levers is that none succeeds in isolation. Cost savings from better procurement can be lost to a leaky distribution system; a well-designed distribution network cannot compensate for chronic underfinancing; and price regulation without supply reliability simply relocates the shortage. The evidence points toward coordinated action across stages rather than single-point fixes (Bigdeli et al., 2013; Seidman & Atun, 2017). 5.2 The central evidence gap Despite the breadth of this literature, a specific and consequential gap recurs. The evidence on supply chain performance and the evidence on affordability are largely developed in parallel rather than connected. Operations and logistics studies measure stockout rates, lead times, fill rates, and wastage; pricing and health-economics studies measure price ratios, mark-ups, out-of-pocket burden, and catastrophic expenditure. Comparatively few analyses link the two directly, tracing how a defined improvement in supply chain performance translates into a measurable change in the price a patient pays or in the affordability of a treatment course. Even well-conducted systematic reviews note that the empirical base for many pharmaceutical policy and supply interventions in these settings remains limited, and that methodological inconsistency hampers comparison across studies (Cameron et al., 2009; Seidman & Atun, 2017). The price-component and pooled-procurement literatures show that the connection is tractable in principle. The price-component method already decomposes the patient price into stage-specific add-ons, and the pooled-procurement evidence already reports price effects of specific procurement reforms (Kok et al., 2022; World Health Organization & Health Action International, 2008). What is largely missing is the study design that carries a supply chain intervention through to its patient-level price and access effect within the same analysis, reporting logistics metrics and affordability metrics on a common footing. Until that design becomes common, the affordability return on supply chain investment will remain inferred rather than measured (Zaffran et al., 2013). This gap matters for practice. Without integrated analyses, decision-makers cannot easily weigh a logistics investment against a financing reform on a common scale, because the affordability return on supply chain improvement is rarely quantified. Closing the gap would require studies that carry an intervention through to its patient-level price and access effects, and that report supply chain metrics and affordability metrics together rather than separately (Kremer et al., 2023). 5.3 From levers to sequence: implementation and measurement Knowing the leverage points is not the same as knowing the order in which to apply them, and the implementation literature suggests that sequence matters. Several of the levers are prerequisites for others. Demand visibility through functioning information systems is a precondition for accurate quantification, which is in turn a precondition for procurement, whether pooled or not, to buy the right quantities; pooling that aggregates inaccurate forecasts simply aggregates error (Yadav, 2015; Yaroson et al., 2019). Quality assurance is a precondition for both generic substitution and lowest-price procurement, because without it a price-minimizing strategy selects for substandard products (Hassali et al., 2014). Financing reliability underlies all of them, since the most efficient procurement and distribution design cannot function on budgets that arrive late or unpredictably (Seidman & Atun, 2017). A defensible sequence therefore tends to begin with information and financing foundations, proceed to quality-assured procurement and distribution IJHPR redesign, and layer pricing and competition policy on top, rather than attempting every reform simultaneously or beginning with the most politically visible measure. Implementation also depends on governance conditions that the technical literature sometimes understates. Pooled procurement requires members to cede some autonomy to a common entity and to trust its independence; mark-up regulation requires the administrative capacity to monitor and enforce; price transparency requires the authority to compel disclosure (Bigdeli et al., 2013; Kok et al., 2022). These are political and institutional achievements as much as technical ones, and their absence explains why reforms that work in one setting fail in another despite similar designs. The systematic evidence on pooled procurement is explicit that organizational structure must be aligned with goals and adapted to local conditions, a finding that generalizes to the whole reform agenda (Kok et al., 2022). Measurement is the thread that ties implementation to accountability. The standardized price- component methodology provides a common language for prices and their composition, allowing a country to track whether a reform actually reduced the add-ons it targeted (World Health Organization & Health Action International, 2008). Frameworks for pharmaceutical systems strengthening have sought to define measurable constructs so that system performance can be assessed rather than asserted (Hafner et al., 2017). The recurring recommendation across recent syntheses is to monitor availability, price ratios, mark-up structure, stockout frequency, and the prevalence of poor-quality products together, and to do so over time, so that the effect of reforms can be observed and mid-course corrections made. Without such measurement, reforms proceed on faith, and the evidence gap identified above, the disconnect between supply performance and affordability, is perpetuated at the level of individual programs as well as in the literature (Nisingizwe et al., 2022). Figure 3 sets out the principal determinants of medicine affordability for patients and payers. Figure 3. Determinants of medicine affordability. 5.4 The political economy of price and procurement reform The levers that most reduce the patient price, competitive tendering, pooled purchasing, reference pricing, and the rationalization of distribution margins, are technically well understood, yet they are adopted unevenly and often reversed, and the explanation lies less in technical difficulty than in the distribution of interests that any reform disturbs. Procurement reform threatens established suppliers and the intermediaries whose margins it compresses, transparent pricing exposes IJHPR arrangements that some participants prefer to keep opaque, and the consolidation of fragmented purchasing shifts authority and the rents attached to it. A purely technical account of affordability therefore explains what should be done without explaining why it so often is not (Roberts et al., 2008). Recognizing the political economy of reform reframes the affordability problem as one of building the coalitions and the sequencing that make change durable. Reforms that concentrate benefits on a diffuse population of patients while imposing concentrated costs on identifiable incumbents are politically fragile, because the losers are organized and the beneficiaries are not, and they survive only where they are designed with attention to this asymmetry. Demonstrating benefit through a contained pilot, protecting the legitimate interests that reform displaces, and creating constituencies with a stake in the new arrangement are the conditions under which a technically sound reform becomes politically sustainable. This perspective does not weaken the case for the price and procurement levers; it explains the gap between their evident merit and their patchy adoption, and it locates that gap in the institutional and political terrain rather than in any doubt about the economics. For a programme seeking to lower the patient price, the implication is that the analysis of what to do must be paired with an analysis of how to make it stick, since a reform that is announced but not defended against the interests it disturbs will deliver l