Effects of shock economic policies on access to essential medicines among older adults in Argentina: an interrupted time-series analysis (2021–2026)

Argentina provides a model case for studying medication-affordability vulnerability under macroeconomic shock. In high-inflation settings, formal medicine availability may coexist with declining affordability when medicine prices outpace the incomes of vulnerable populations. This study assessed how the affordability of chronic outpatient medicines evolved among minimum-pension retirees in Argentina before, during, and after the December 2023 macroeconomic shock. We constructed a balanced panel of 9,910 specific commercial presentations (SCP) between June 2021 and March 2026, comprising 584,690 SCP-month-observations. Official inflation and minimum pension series were obtained from the National Institute of Statistics and Censuses and the National Social Security Administration. Affordability was estimated as the share of one minimum pension required to purchase 30 defined daily doses across eight outpatient therapeutic families. Interrupted time-series models with fixed effects for specific commercial presentations were fitted, distinguishing pre-shock, acute-shock, and post-shock phases. Between June 2021 and March 2026, the median cumulative price increase was 1,951%, compared with 2,191% cumulative inflation and a 1,502% increase in the minimum pension. Before the shock, affordability was already deteriorating across all therapeutic families. During the shock, purchasing power fell sharply. By March 2026, the affordability burden remained above the pre-shock average in all families, with the largest excess burden observed for antiparkinsonian (+ 31.5%; 95% CI, 14.8 to 50.5), antithrombotic (+ 22.8%; 95% CI, 15.9 to 30.0), and antipsychotic medicines (+ 20.2%; 95% CI, 14.5 to 26.2). Argentina shows how macroeconomic shock can rapidly translate price increases into reduced medication affordability. Pharmaceutical policy requires countercyclical mechanisms capable of protecting purchasing power among vulnerable populations.