Abstract Background The number of older adults from ethnic minority communities (EMCs) in England and Wales particularly those aged 60 and above is increasing. This demographic change, which is usually coupled with the prevalence of polypharmacy among these populations presents unique challenges in the context of medicine optimisation. Failure in this context can lead to exacerbated health disparities, non-adherence, and inappropriate prescribing (whether over or under). This review builds on the MEMORABLE study which was also a realist study that explored medication management in older people. This study aims to understand the complexities of medicine optimisation and what works and does not work, when and under what circumstances for older adults from EMCs. Key possible areas include cultural backgrounds, traditional beliefs, and systemic barriers that may influence health-seeking behaviours and medicine optimisation. Methods The review follows the five-step approach. Firstly, we will establish initial program theories to highlight the expected context, mechanisms, and outcomes. Following this, a formal search for evidence will be conducted. The third step involves the selection and appraisal of studies, studies will be screened by title, abstract/keywords and full text against inclusion and exclusion criteria. In the fourth stage, data from these studies will be extracted, recorded, and coded. The final step will synthesise this information, to test, refine, and expand our initial programme theories to understand how medicine optimisation works or does not work in these populations. Discussion This review will be conducted in line with the RAMESES reporting standards. This will include publishing the review in a scientific journal and submitting abstracts for presentation at both national and international primary care and pharmacy practice conferences. Once we improve the understanding of how medicine optimisation works for these populations with polypharmacy in primary care effective interventions can be developed. Systematic review registration PROSPERO registration number CRD42023432204 Keywords Multimorbidity Person-centered care Medication review Medication management Cultural competence Deprescribing Overprescribing Under prescribing.

The authors have declared no competing interest.

This work is supported by HMMCT.

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