Effective Implementation of Medicines Shortage Policy: Evidence from Australia’s Serious Scarcity Substitution Instruments

Abstract Background Medication shortages are a considerable and ongoing issue in healthcare, disrupting consumer access. Since 2021, Australia’s national medicines regulator has issued Serious Scarcity Substitution Instruments (SSSIs), allowing pharmacists to substitute a specific therapeutically equivalent strength and/or formulation of a medicine without prior approval from a prescriber. The impact of SSSIs on utilisation of medicines has not been investigated. Objective Determine whether SSSIs are effective in addressing medicine shortages and meeting patient need. Methods This retrospective cohort study used aggregated pharmacy claims to examine the utilisation of 12 medicines which had an SSSI. We calculated the percentage change in defined daily doses dispensed per 1000 population per day in the 11 months after SSSI implementation, compared with the previous two years. A percentage change of less than 20% was used to indicate success. Results Following product shortages, utilisation fell for 10 of the 12 medicines examined. For eight of these medicines (amoxicillin, cefalexin, estradiol, fluoxetine, insulin degludec with insulin aspart, isosorbide mononitrate, vigabatrin, and warfarin) decreases in utilisation were minimised to