Evaluating the impact of varenicline shortages and a regulatory mitigation strategy on dispensing patterns of smoking cessation therapies in Australia: A retrospective interrputed time series study

Abstract Background and aims Australia experienced a prolonged varenicline shortage beginning June 2021, disrupting access to a key smoking cessation therapy. Section 19A (S19A) of the Therapeutic Goods Act permitted temporary importation of overseas‐approved products to mitigate this impact. We aimed to examine dispensing trends for varenicline and alternative therapies during the shortage and evaluate the effectiveness of S19A interventions. Design Retrospective study using interrupted time series analysis with two intervention points: shortage impact June 2021 and mitigation with S19A medicines May 2022. Setting Australia; national Pharmaceutical Benefits Scheme (PBS) dispensing data. Cases Aggregate monthly dispensings of varenicline, bupropion and nicotine products from January 2018 to May 2025. Measurements Defined Daily Dose per 100 000 population per day (DDD/100 000/day); estimated missed varenicline doses calculated by comparing expected vs. actual dispensings. Results Varenicline use declined from 96.14 DDD/100 000/day (Feb 2018) to 0.29 (Mar 2022). S19A imports commenced 11 months after the shortage began, accounting for 38% of dispensings between May 2022 and June 2024. The decline equated to 1319 fewer individuals receiving varenicline for one year at standard dosing. Bupropion use increased from 5.71 to 16.63 DDD/100 000/day post‐shortage, while nicotine use declined. Pre‐shortage varenicline levels were not restored. Summary The varenicline shortage in Australia from June 2021 substantially disrupted subsidised smoking cessation pharmacotherapy. Regulatory interventions and increased bupropion use partially mitigated the impact but were insufficient to maintain prior access.