Has the rescheduling of modified-release paracetamol in Australia affected the frequency of overdoses?

OBJECTIVES: In June 2020, modified-release paracetamol (paracetamol-MR) preparations were up-scheduled from schedule-2 (available in pharmacy) to schedule-3 (available by request to a pharmacist only). The present study aims to ascertain whether up-scheduling affected the frequency of paracetamol-MR overdoses. METHODS: This is a retrospective cohort study of two data sets from 1 June 2017 to 31 May 2022. Monash Health data were extracted using the diagnosis of paracetamol overdose coding and electronic medical records data. Calls regarding paracetamol-MR overdoses to Victorian Poisons Information Centre (VPIC) were extracted from the Poisons centre call database. We used a quasi-experimental research design with interrupted time series analysis to evaluate the immediate impact and change in trend of poisoning-related calls and ED presentations before and after June 2020. The change in proportion of paracetamol-MR cases in both databases was analysed using the Χ2 test. RESULTS: The proportion of paracetamol-MR cases in both data sets did not change. From Monash Health, there was no level change in monthly paracetamol-MR overdose-related presentations following re-scheduling (rate ratio [RR] = 1.08, 95% confidence interval [CI] = 0.57-2.01). There was no change in monthly paracetamol-MR overdose-related calls to VPIC following re-scheduling (RR = 1.05, 95% CI = 0.96-1.14). CONCLUSION: The proportion of paracetamol-MR overdoses did not decrease after the up-scheduling to S3. Similarly, the frequency of overdoses by month remained similar. Further limitations on access to paracetamol products may need to be considered.

Designed Y3+ Surface Segregation Increases Stability of Nanocrystalline Zinc Aluminate.

The thermal stability of zinc aluminate nanoparticles is critical for their use as catalyst supports. In this study, we experimentally show that doping with 0.5 mol % Y2O3 improves the stability of zinc aluminate nanoparticles. The dopant spontaneously segregates to the nanoparticle surfaces in a phenomenon correlated with excess energy reduction and the hindering of coarsening. Y3+ was selected based on atomistic simulations on a 4 nm zinc aluminate nanoparticle singularly doped with elements of different ionic radii: Sc3+, In3+, Y3+, and Nd3+. The segregation energies were generally proportional to ionic radii, with Y3+ showing the highest potential for surface segregation. Direct measurements of surface thermodynamics confirmed the decreasing trend in surface energy from 0.99 for undoped to 0.85 J/m2 for Y-doped nanoparticles. Diffusion coefficients calculated from coarsening curves for undoped and doped compositions at 850 °C were 4.8 × 10-12 cm2/s and 2.5 × 10-12 cm2/s, respectively, indicating the coarsening inhibition induced by Y3+ results from a combination of a reduced driving force (surface energy) and decreased atomic mobility.