Structural Patterns of Antibiotic Shortages: A Cross-National Analysis of Systemic Antibacterials

Background/Objectives: Drug supply disruptions represent an increasingly serious problem for health systems worldwide, with systemic antibiotics among the most frequently affected therapeutic categories. Although regulatory authorities have repeatedly signaled this risk, comparative studies analyzing patterns of antibiotic shortages across multiple countries simultaneously remain scarce. Methods: We performed a cross-sectional comparative analysis based on data from public national shortage registries in seven jurisdictions: Belgium, France, Germany, Romania, Spain, the United States (FDA), and the Kingdom of Saudi Arabia. All records corresponding to systemic antibiotics in ATC group J01 were extracted, harmonized, and analyzed, with the active substance (INN) as the unit of analysis. The association between critical drug status according to the EMA list and the multinational recurrence of shortages was assessed using chi-square tests, the Mann–Whitney U test, and multivariate logistic regression. To verify the robustness of the results, a sensitivity analysis was also performed using alternative thresholds for jurisdictions. Results: A total of 350 shortage records were mapped, corresponding to 64 unique active pharmaceutical ingredients. On average, each active substance was reported as out of stock in 3.48 jurisdictions (SD = 1.46). Macrolides (J01F) and quinolones (J01M) exhibited the widest geographic spread of shortages. Antibiotics included on the EMA’s list of critical medicines were reported as missing in multiple countries simultaneously significantly more frequently than those not included on this list (82.86% vs. 37.14%; χ² = 71.99, p < 0.001; Cramer’s V = 0.454). In the multivariate logistic regression model, EMA critical medicine status remained an independent predictor of multinational recurrence of shortages (OR = 8.29; 95% CI: 4.93–13.94; p < 0.001), while the injectable route of administration did not reach the threshold for statistical significance (OR = 0.78; p = 0.341). Sensitivity analysis confirmed that this association remains statistically significant regardless of the threshold chosen. Conclusions: Shortages of systemic antibiotics tend to occur simultaneously in multiple countries, and drugs designated as critical by the EMA are disproportionately affected. The results suggest that the identified weaknesses are not specific to a single health system but reflect structural fragilities in international antibiotic supply chains. This underscores the need for internationally coordinated strategies, both for monitoring the availability of essential antibiotics and for preventing and managing shortages.