The World Health Organization (WHO) defines access to medicines as a priority concern, indicating that essential medicines must be available and accessible at all times, in adequate quantities, in appropriate dosage forms and quality, and at affordable prices for all patients ([47]). Medication access is the ability of patients to obtain prescribed medicines in a timely, affordable, and appropriate manner ([46]). The prescription fill rate is the proportion of prescribed medicines actually dispensed to a patient, expressed as a percentage ([49]). When availability is compromised, some of the consequences include delayed treatment, adverse drug events, medication errors, increased healthcare costs, prolonged hospitalizations, and preventable deaths ([38]). The WHO promotes the rational use of medicines by ensuring that patients receive treatments appropriate to their clinical needs, in doses that meet individual requirements, for adequate periods, and at the lowest possible cost ([12]). In addition, supply chain inefficiencies frequently disrupt prescribing practices, resulting in irrational prescribing, therapeutic substitution, and incomplete treatment courses ([36]; [15]; [21]; [22]). Significantly, it is estimated that more than half of all medicines globally are prescribed or dispensed irrationally, and that irrational prescribing itself reduces medicine availability by as much as 50%, creating a cycle of wastage and scarcity ([17]).

Despite increased investments in procurement of essential medicines globally, their availability at health facilities remains critically low in many LMICs, a situation largely driven by supply chain bottlenecks ([44]). A systematic scoping review of medicine availability across Africa, encompassing 198 availability studies, found that most measures classified public facility medicine availability as low (<50%) at the primary care level ([16]).

The WHO has developed five core prescribing indicators to measure the rationality of prescribing at the facility level ([49]). These indicators include: 1) the average number of medicines per patient encounter (WHO optimal: 1.6 - 1.8), 2) the percentage of medicines prescribed by generic name (WHO optimal: 100%), 3) the percentage of patient encounters with an antibiotic prescribed (WHO optimal: ≤20% - 26.8%), 4) the percentage of patient encounters with an injection prescribed (WHO optimal: 13.4% - 24.1%), and 5) the percentage of medicines prescribed from the Essential Medicines List (WHO optimal: 100%).

The economic consequences of inaccessibility are equally significant: when public facilities lack essential medicines, patients are compelled to purchase from private pharmacies at substantially higher out-of-pocket costs, further entrenching health inequity ([48]). Against this backdrop, improving medication access rates at the primary care level in SSA is not merely a logistical challenge but a matter of fundamental public health urgency.

This review organizes evidence from global, regional, and local literature on health supply chain bottlenecks and their influence on medication access and prescribing practice, with a particular focus on public health facilities in SSA ([41]; [32]). Specifically, the narrative review seeks to: 1) assess evidence of the key supply chain bottlenecks that may affect essential medicine availability, 2) review evidence of the association between health supply chain bottlenecks and medication access, and 3) review evidence of the association between health supply chain bottlenecks and prescribing practices consistent with the WHO Drug Use Indicator framework.

The conceptual framework is grounded in the WHO Health Systems Building Blocks framework, which identifies six interconnected components of a functional health system: service delivery, health workforce, health information systems, access to essential medicines, financing, and leadership and governance (Figure 1). This review draws on the “access to essential medicines” building block as its primary domain.

The framework proposes two associational pathways through which health supply chain bottlenecks may be linked to medication access and prescribing practices. In the first pathway, supply chain bottlenecks such as poor demand forecasting are associated with reduced availability of essential medicines and low prescription fill rates at the point of care.

Figure 1. Conceptual Framework indicating factors that influence access to medication and prescribing practices of medicines in healthcare facilities.

In the second pathway, supply chain bottlenecks are associated with distortions in prescribing practices in that prescribers may deviate from standard prescribing guidelines to adapt to supply chain challenges by selecting alternative agents or substituting suboptimal medicines for unavailable preferred options. These patterns are associated with observable deviations across the WHO prescribing indicators.

Consistent with the scope of a narrative review, this framework does not assert a causal relationship; rather, it proposes that health supply chain bottlenecks are associated with medication access and prescribing practices, and this association is the primary focus of this review.

This study employed a narrative review design to synthesize existing literature on health supply chain bottlenecks and their association with medication access and prescribing practices in Sub-Saharan Africa. A narrative review approach was considered most appropriate because the topic covers multiple disciplines, including pharmaceutical supply chain management, public health systems strengthening, antimicrobial stewardship, and rational medicine use. The available evidence is highly diverse in terms of study designs, outcome measures, health system levels assessed, and methodological approaches, making statistical pooling or meta-analysis inappropriate.

A comprehensive literature search was conducted between March 2026 and May 2026 using academic databases including Google Scholar, PubMed, and ScienceDirect. The publication date limits for the included studies were set from January, 2009 to May, 2026 for all databases. The major search terms and combinations used included; health supply chain or pharmaceutical supply chain bottlenecks and stockout or medicine shortage; Sub Saharan Africa or low- and middle-income country and medication access or prescription fill rate; Sub Saharan Africa or low- and middle-income country and prescribing practices or WHO prescribing indicators or irrational prescribing. The sequential screening approach was used, firstly, the title and abstract were screened by the first author and a sample of excluded records was independently verified by the second author to confirm correct exclusion, with disagreements resolved by consensus. Secondly, full-text eligibility assessment and data extraction were likewise conducted by the first author and cross-checked by the second author for all included sources.

The screening and data extraction procedures were conducted using a structured review process and included consistency checks among the authors to improve transparency and rigor. No language restrictions were applied at the search stage, although only English-language records were subsequently retained. The study included peer-reviewed studies published in English between January 2009 and May 2026. The initial search yielded 245 records across all three databases (Google Scholar, PubMed, and ScienceDirect), with 18 additional records identified through reference lists and institutional reports. After removal of duplicates, 218 unique records were screened by title and abstract against the eligibility criteria. Of these, 70 full-text sources were assessed for eligibility, and a final set of 50 studies and reports was included in the narrative synthesis. The selection process is summarized in Figure 2 below. A narrative review design was chosen over a systematic review because the topic spans multiple disciplines with highly heterogeneous study designs, diverse outcome measures, and varied methodological approaches, making statistical pooling inappropriate for this broad health systems question.

Studies were included if they addressed one or more of the following review objectives: 1) health supply chain bottlenecks or inefficiencies; 2) medication access outcomes; or 3) prescribing practices, including the WHO prescribing indicators. The review synthesized evidence across these interconnected domains to construct the broader narrative framework. Additionally, studies were included if they: 4) were published between January 2009 and May 2026; and 5) were written in English and published in peer-reviewed journals or credible institutional reports. Private sector supply chains, or high-income country contexts, were excluded unless they provided global-level benchmarks relevant to the review. The selection process followed a sequential screening approach: records were first screened by title and abstract, and those meeting the thematic criteria were retrieved in full text for final inclusion assessment. Studies that did not report on supply chain performance, medication access, or prescribing practices in the LMIC context were excluded at the full-text stage. Although a formal PRISMA flow diagram is not required for narrative reviews, the overall selection process is summarized in Figure 2 to support transparency and reproducibility.

Figure 2. Literature selection flow diagram.

Data extraction was conducted thematically. For each included study, the following information was extracted: country or region of study, level of the health system examined, supply chain bottlenecks identified where available, medication access outcomes where available (including prescription fill rates), prescribing practice outcomes where available (including WHO prescribing indicator values), and key recommendations. Evidence was then synthesized narratively under three geographic strata: global, Sub-Saharan Africa, and local (Zambia), consistent with the review objectives. Quantitative prescribing data were tabulated for comparative analysis against WHO reference values.

Given the narrative review design, formal risk-of-bias assessment tools such as CASP or Cochrane appraisal frameworks were not uniformly applied. This represents an inherent limitation of narrative reviews compared with systematic reviews, which typically employ standardized quality appraisal and reproducible evidence synthesis procedures. Consequently, the findings presented should be interpreted as a broad thematic synthesis of available evidence rather than a quantitatively weighted assessment of study quality.

However, several measures were undertaken to enhance rigor, transparency, and credibility. These included the use of predefined eligibility criteria, structured database searching across multiple sources, sequential title/abstract and full-text screening, and thematic extraction of key study variables. Priority was also given to peer-reviewed and indexed studies, while findings were triangulated across multiple countries, study settings, and methodological approaches to improve consistency of interpretation. Where conflicting findings existed, both perspectives were reported and critically discussed. Regarding the appraisal of evidence types: peer-reviewed and indexed literature were accorded the highest priority during interpretation and synthesis. Institutional or governmental reports and grey literature were included primarily to provide contextual and policy-relevant insights. The findings were triangulated across multiple study designs, countries and methodologies to improve consistency and credibility. The review did not apply formal quantitative weighting because of the narrative review design and heterogeneity of the evidence base.

Furthermore, limitations within the primary literature itself, including reliance on cross-sectional designs, inconsistent measurement of supply chain indicators, self-reported outcomes, and limited evidence from primary healthcare settings, were explicitly acknowledged throughout the review.

Globally, several key bottlenecks have been identified within pharmaceutical supply chains. These include unreliable data systems that hinder forecasting and decision-making, weak regulatory frameworks, corruption, inadequate funding, shortages of skilled personnel, and bureaucratic procurement processes ([27]; [2]). Poor infrastructure and weak information-sharing mechanisms among supply chain stakeholders further contribute to operational inefficiencies, resulting in delays, stockouts, and medicine wastage ([41]; [36]). Inadequate inventory management also negatively impacts medication access and patient health outcomes ([5]), as poor inventory controls can lead to drug expiry and the availability of substandard medicines.

Bottlenecks equally manifest through delayed delivery schedules, contributing to poor availability and wastage of essential medicines in public health facilities ([47]). They are further observed at the point of care through ineffective implementation of Standard Operating Procedures (SOPs) and related policies, which contribute to irrational prescribing and inefficient medicine use ([3]). Furthermore, the availability of essential medicines is a prerequisite for their accessibility to patients ([19]). Medicine shortages result in patients being forced to seek care at other facilities or purchase medicines from private pharmacies at significantly higher personal cost, all of which adversely affect prescription fill rates and patient outcomes ([41]).

It is important to note at the outset that prescribing practice is multifactorial: while supply chain performance is a significant contributor, clinical training, diagnostic capacity, patient demand, antimicrobial stewardship programs, and governance frameworks all independently shape prescribing decisions. The evidence presented here does not establish causation but rather demonstrates a strong associational relationship between supply chain performance and prescribing outcomes. Where an individual study measured both supply chain performance and prescribing outcomes within the same setting and sample, this is noted as direct evidence. Where the association is inferred by comparing findings from separate studies conducted in different settings or time points, this is described as inferential evidence. The majority of evidence in this review is inferential in nature, reflecting the current state of the literature.

Supply chain inefficiencies globally have been associated with distorted prescribing practices. The WHO estimates that more than half of all medicines are prescribed or dispensed irrationally, with irrational prescribing reducing medicine availability by as much as 50% ([17]). Evidence from Central India found that 47% of prescriptions were irrationally prescribed, with only 19% of prescriptions containing complete dosing information, further illustrating the pervasive nature of this problem ([18]). Similarly, a study conducted in Ethiopia found that irrational drug use was common among outpatients, with polypharmacy and antibiotic overprescribing identified as significant concerns: antibiotic prescribing in some Ethiopian facilities exceeded 66.5% of all encounters, far above the WHO optimal of ≤20% - 26.8% ([23]).

Additionally, supply chain managers frequently fail to share critical information such as current stock status with prescribers; this miscommunication not only increases wastage but also prolongs the time required to dispense correct medicines and adequately fulfil prescription orders ([6]; [36]). Multiple interacting factors shape prescribing decisions, including educational background, workplace conditions, and the pharmaceutical market environment ([8]), making it difficult to attribute irrational prescribing to supply chain factors alone. However, the evidence suggests these factors are not independent: supply shortages create conditions in which even well-trained prescribers are compelled to deviate from rational prescribing guidelines.

In Sub-Saharan Africa and other low-resource settings, pharmaceutical supply chains encounter systemic challenges that significantly affect medicine availability. Studies have identified weak regulatory systems, persistent medicine stockouts, poor demand forecasting capacity, and inadequate human resources as major bottlenecks ([28]; [35]; [2]). Corruption, political instability, and severe financial constraints further disrupt procurement and distribution systems throughout the region ([32]). Problems associated with medicine availability in public hospitals have been attributed to budget shortages, bureaucratic delays, distribution failures, lack of skilled personnel, inappropriate selection of medicines, and an inability to accurately estimate requirements ([27]).

Country-level evidence from across the region demonstrates the breadth and consistency of supply chain failures. In Kenya, shortages of medical supplies in public health facilities prevented patients from accessing subsidized essential products ([9]). In Uganda, despite commitments to improving accessibility and availability of essential drugs, actual realization remains poor and structural bottlenecks at each stage of the supply chain have not been systematically identified or documented ([31]). In South Africa, procurement inefficiencies caused medicine parcels to reach facilities without all prescribed medicines, substantially increasing pharmacy workloads and creating barriers to timely patient care ([20]). In Nigeria, systemic weaknesses in outbound pharmaceutical value chains, including distribution infrastructure, regulatory gaps, and procurement bureaucracy, were found to worsen stockout frequency and duration ([2]; [32]).

Shortages of essential medicines in clinic settings have also been associated with poor stock control and management practices, particularly in nurse-managed pharmacies at primary health facilities ([50]). While these findings represent distinct national contexts, they share a common pattern: supply chain failures concentrated at the last mile, compounded by human resource constraints and weak information systems.

Association with Medication Access and Prescribing Practices across the Region

In South Africa, a survey of 231 facilities documented 609 stockout events over three years, with antiretroviral medications alone accounting for 78% of all reported stockouts ([45]), illustrating how stockouts concentrate around the medicines most critical to survival. Similarly, another study in South Africa demonstrated that stockouts resulted in medicine parcels being dispatched to health facilities with incomplete supplies of prescribed medicines ([20]). In Zambia, a large-scale randomized experiment across 439 health facilities found stockout frequencies for first-line pediatric malaria medicines as high as 47.9% under standard supply chain arrangements ([44]).

Global studies highlight that PFRs are closely associated with the overall performance of pharmaceutical supply chains; poor communication between logistics managers and prescribers often delays medication access and reduces prescription fulfilment rates ([36]). In Eritrea, where supply chains were better coordinated, 87% of available drugs were adequately dispensed in referral hospitals ([40]), demonstrating direct evidence of how improved supply chain performance translates directly into better prescription fill rates.

The potential association between supply chain bottlenecks and prescribing practices has been partially documented across Africa, though the evidence base remains incomplete and largely associational. A narrative review of antibiotic use across Sub-Saharan African hospitals found prevalence rates ranging from 37.7% in South Africa to as high as 80.1% in Nigeria, with the majority of facilities exceeding 50%, all substantially above the WHO optimal of ≤20% - 26.8% ([39]). Considerable prescribing of broad-spectrum antibiotics was found across the region, often driven by the absence of microbiological diagnostic facilities and concerns about co-payments for laboratory tests, resulting in widespread empiric prescribing ([39]). In Zambia, antibiotics were found to constitute 72.3% of all patient encounters in a post-COVID hospital study ([26]), substantially exceeding the WHO optimal. In Ethiopia, antibiotic encounter rates were reported between 44.5% and 85% across different facilities, consistently surpassing WHO benchmarks and reflecting the compounding effect of stockouts on irrational prescribing ([23]). A qualitative study in Addis Ababa primary healthcare facilities assessed both supply chain constraints and prescribing practice at the same facilities and revealed that supply shortages, absent treatment guidelines and non-review of patient history pose a direct association on private sector prescribing ([4]).

The following tables provide structured syntheses of the evidence reviewed:

1) Table 1: Summarizes medicine access rates across selected countries and regional contexts.

2) Table 2: Document stockout prevalence and contributing supply chain bottlenecks.

3) Table 3: Presents observed prescribing practices in SSA against the WHO prescribing indicator reference values.

Table 1. Medicine access rates in Sub-Saharan Africa and global comparators.

Table 2. Stockout rates and key supply chain bottlenecks by country/region.

Table 3. Prescribing practices against WHO prescribing indicator reference values.

4) Table 4: Presents documented interventions in SSA.

Table 4. Documented interventions to address supply chain bottlenecks and prescribing irrationality in Sub-Saharan Africa.

Table 1 reveals a consistent disparity in medicine access between high-income settings and public health facilities across Sub-Saharan Africa. Globally, essential medicine accessibility in public facilities averages as low as 29.4% across WHO regions, with prescription fill rates falling to 30% - 60% at the primary care level in LMICs, far below the near-universal access observed in well-resourced settings. Within the SSA region, availability is consistently classified as low (below 50%) in most public primary care contexts, driven by last-mile distribution failures, procurement shortfalls, and weak inventory management.

Table 2 maps the depth of supply chain failures across SSA and demonstrates that medicine stockouts are not random or isolated events but reflect structural bottlenecks embedded at multiple levels of the pharmaceutical supply chain. Globally, drug shortages affect more than 50% of countries, with the burden disproportionately concentrated in LMICs. At the regional level, 40% - 60% of primary health facilities in SSA experience regular stockouts, a figure that exceeds 60% in some country surveys driven by weak inventory management, last-mile distribution failures, and inadequate human resources.

Table 3 presents evidence that prescribing practices across SSA deviate substantially from WHO optimal benchmarks. These deviations appear to be associated with supply chain failures, though multiple factors, including prescriber training, diagnostics availability, and patient demand, are also likely contributors. The most striking pattern is the overuse of antibiotics: antibiotic encounter rates range from 37.7% in South Africa to as high as 85% in Ethiopia and 80.1% in Nigeria, all substantially exceeding the WHO optimal threshold of 20% - 26.8%. Polypharmacy is equally concerning, with medicines per patient encounter reaching up to 4.8 in some Ethiopian facilities against a WHO optimal of 1.6 - 1.8.

Table 4 presents the key interventions documented across SSA to address supply chain bottlenecks and prescribing irrationality, revealing a landscape of promising but unevenly implemented and underexplored strategies. Electronic Logistics Management Information Systems (eLMIS) have demonstrated clear benefits in reducing reporting turnaround times and improving inventory visibility; however, their impact remains constrained by connectivity challenges in remote areas, poor data entry quality, and inadequate staff training barriers that are especially pronounced at the primary care level, where they are needed most.

In Zambia, the primary distribution of essential medicines is managed by the Zambia Medicines and Medical Supplies Agency (ZAMMSA), while secondary distribution falls under the responsibility of District Health Management Teams (DHMTs) ([14]). At the district level, supply chain performance depends heavily on coordination between facility staff and district health offices. Despite district officers providing technical support and monitoring ordering patterns, inefficiencies in reporting and demand forecasting are still linked to medicine shortages and delayed deliveries ([44]). A study in Ndola District found that approximately 40% of health facilities experienced regular stockouts of essential medicines, reflecting systemic supply chain failures despite substantial national investments ([29]).

Consistent with findings in Sub-Saharan Africa, facilities in remote areas face particularly acute challenges arising from inadequate transportation infrastructure, while urban facilities encounter inefficiencies in inventory management ([30]). These challenges are worsened by poor data quality, weak inventory management systems, and limited technical capacity among health workers responsible for supply chain management ([33]).

Health supply chain bottlenecks in Zambia limit access to essential medicines, reduce prescription fill rates, and compel patients to seek treatment from private pharmacies or alternative facilities ([41]). Additionally, supply chain constraints were associated with antibiotics constituting 72.3% of all patient encounters post-COVID, far exceeding the WHO optimal range, which compromised AMS efforts ([26]).

Table 5 translates the cumulative evidence from this review into six clearly defined and evidence-grounded policy priority areas, providing a practical roadmap for governments, health ministries, and international partners. Each recommendation is directly anchored to a documented supply chain failure identified in the reviewed literature, making Table 5 both a diagnostic and prescriptive tool. Together, the six priority areas represent a multi-level, interconnected policy response that mirrors the complexity of the supply chain system itself, and underscore that gradual interventions targeting only one level of the supply chain will be insufficient to achieve sustained improvement in medicine access and prescribing quality across SSA.

Table 5. Policy implications and strategic recommendations arising from the review.

Therefore, beyond facility and district-level interventions, this review underscores the value of sub-regional collaboration across Africa in procurement and manufacturing, which has the potential to transform the structural determinants of medicine accessibility across SSA. Additionally, investment in road infrastructure would help mitigate or cushion the occurrence of last mile distribution failures. These recommendations are broader strategic proposals extrapolated from the identified structural bottlenecks, rather than interventions directly evaluated within the reviewed studies.