**3. Results**

From the initial literature search, a total of 2748 articles were identified across 7 databases (Figure A1). Following the removal of duplicate articles, titles and abstracts were screened for our key concepts, resulting in 21 articles being selected for full text assessment and a final 7 selected for inclusion. No studies were identified in our search when (1) and (5), and (4) and (5) were combined (Figure A2). There were no CMs' scheduling studies identified in the search conducted. All studies focused on the impact of scheduling codeine products, and this was judged as relevant to understanding more broadly what needs to be considered in the scheduling of any medicines, including CMs.

Four of the studies examined the perceptions and perspectives of pharmacists in relation to the up-scheduling of codeine. Two quantitative studies examined retrospective data from the Poison Information Centres, in Australia and Ireland. One study explored the characterization of Schedule 2, Schedule 3, and unscheduled medicines. As presented in Table 1, five themes were identified related to the purpose, attitudes, and implications.
