What Brexit Did to Medicine Availability
I learned what a medicine shortage means before I ever modelled one. In Damascus pharmacies, dispensing through years of supply instability, I watched shortages arrive not as headlines but as substitutions, rationing decisions, and conversations with patients about what was not on the shelf. When I came to the University of Edinburgh to study global health policy, I brought a question with me: when a rich, well-governed system faces a supply shock, what actually protects patients?
Brexit offered a rare natural experiment. Before 2021, around three quarters of UK medicines relied on EU supply chains, supported by regulatory alignment, mutual batch testing and frictionless trade. Brexit introduced regulatory fragmentation: new MHRA arrangements splitting Great Britain from Northern Ireland, the loss of batch-testing recognition, customs friction, and exit from EU joint procurement. Then COVID-19 landed on top, a compounded stress test of the whole system. Shortage notifications doubled between 2016 and 2023. Price concessions peaked at 199 in a single month in 2022.
But headline counts of shortages tell you little about what patients experienced. For my MSc dissertation, I combined structured policy mapping of MHRA and DHSC interventions with interrupted time-series analysis of UK primary care prescribing, using ARIMAX models across four national data sources covering 2010 to 2023. To my knowledge, no prior study had combined structured policy mapping with longitudinal prescribing data across medicine categories in this way.
I chose four medicines deliberately, each representing a different kind of system vulnerability: amoxicillin, a high-volume generic antibiotic; co-amoxiclav, its closest substitute; varenicline, a single-source medicine; and sarilumab, a biologic.
What the data showed
The four medicines told four different stories, and that is the finding.
Amoxicillin fell by more than a third during COVID, meeting the study's threshold for disruption. Prescribing recovered after 2021, but the recovery came with rising costs and routine use of Serious Shortage Protocols, the emergency provisions that let pharmacists supply alternatives without going back to the prescriber.
Co-amoxiclav never met the disruption threshold. Its stable trajectory suggests the system successfully buffered it through substitution and mitigation measures. Where a substitute exists, mitigation works.
Varenicline collapsed, but not because of Brexit. Its decline was driven by a global manufacturing recall in June 2021. The lesson is uncomfortable: for single-source medicines, national policy offered no protection at all. When the sole global supplier stumbles, no domestic mitigation catches the fall.
Sarilumab, the biologic, is the mirror image. Its uptake increased substantially after 2021, supported by the Innovative Licensing and Access Pathway and COVID-era clinical use. Where regulatory support was deliberately built, access did not just survive the turbulence. It improved.
Absorptive, adaptive, not transformative
Put together, the picture is of a system that coped without changing. The UK's mitigation was absorptive and adaptive: it soaked up shocks and adjusted around them. It was not transformative. Serious Shortage Protocols, designed as emergency instruments, became routine coping tools, and a system that normalises its emergency measures is telling you something about its underlying fragility.
Resilience was also unevenly distributed, and the pattern is the study's sharpest policy finding. Biologics were protected, because regulatory attention was designed for them. Generics were exposed to procurement and price pressures. Single-source medicines were effectively unprotected. Disruption and recovery also varied across the four datasets, reflecting uneven policy reach across the UK's devolved systems. Protection, in short, followed policy design rather than patient need.
Why this matters beyond the UK
I did not study Brexit for its own sake. I studied it because it is the best-documented recent case of a health system deliberately rewiring its pharmaceutical supply arrangements, and because the lessons transfer to any country managing medicine supply through disruption, including the one I am from.
Three lessons stand out. First, aggregate shortage counts conceal more than they reveal: vulnerability is category-specific, so monitoring and policy must be too. Second, mitigation that prevents collapse can still leave a system more fragile than before, if emergency tools quietly become permanent ones. Third, resilience is built where regulators choose to build it. The biologics pathway proves that deliberate design protects access; the fate of single-source medicines proves the cost of its absence.
For Syria, where SHEPL's work is focused, these lessons arrive with force. A health system being rebuilt gets to choose its supply architecture rather than inherit it. Real-time prescribing and procurement intelligence, support mechanisms that extend to generics and not only to innovative medicines, and coordination across fragmented authorities are not luxuries for later. They are the difference, my data suggests, between a system that absorbs its next shock and one that is transformed by it.
The UK prevented collapse. The harder task, there and everywhere, is building the kind of system that does not need to keep preventing it.
