Abstract Pharmacogenomics (PGx) is the exploration of how genes impact an individual's reaction to drugs. This emerging field merges the study of drugs (pharmacology) with the study of genes and their functions (genomics). Its goal is to create personalized medications and doses that are safe and effective for each person based on their genetic composition. PGx aims to guarantee that patients receive the appropriate drug at the correct dosage. PGx holds promise for personalized medicine, but its integration into health systems, especially in a developing country like Nigeria, poses significant challenges. This study aimed at exploring the developing an operational model for the implementation of PGx in Nigeria, using the theory of change (ToC) framework. The ToC approach was employed to identify critical preconditions, interventions, and outcomes required to achieve the long-term goal of PGx implementation. Data was collected through mixed-methods, through survey and interviews with multi-stakeholders. The findings were used to explore the development of a potential model for PGx implementation in Nigeria. This is a challenging task because Nigeria, like many low- and middle-income countries, faces many health system challenges such as inadequate infrastructure, limited human resources, and insufficient funding. In the context of these challenges, the ToC framework was applied. The ToC is a management tool used to establish long-term goals and then work backwards to determine the required steps or conditions needed to achieve those goals. The ToC was used to identify the critical factors based on stakeholders needs to identify facilitators for successful PGx implementation in Nigeria which included capacity building, policy development, high-tech equipment and skilled personnel, ethical issues around genetic testing, infrastructure upgrade, public awareness, education and training for health providers, stakeholder and government engagement. The survey revealed that participants had a robust understanding of PGx, with 70% expressing their willingness to incorporate it into their clinical practice. It was found that 37% of respondents foresaw potential applications of PGx in oncology, 22% in infectious diseases, and another 22% in clinical genetics. Challenges hindering the implementation of PGx at the point-of-care were identified as inadequate infrastructure, limited research funding, lack of knowledge and awareness among healthcare professionals (HCPs) and the public, insufficient training for HCPs, inadequate data availability, prohibitive cost of testing, and a lack of governmental policies and regulations. These barriers align with findings from secondary research.

Upon further dialogue, respondents suggested that the presence of an innovative government, enhanced awareness and education on PGx, specialized training for HCPs in PGx testing, the establishment of necessary infrastructure and the provision of technologies for PGx testing, along with appropriate funding, would serve as facilitators for the integration of PGx into healthcare delivery at the point-of-care in Nigeria. This operational model investigated here offers a strategic roadmap for how PGx could be effectively integrated into the Nigerian healthcare system. It could potentially have a significant impact on clinical practice and patient outcomes. The model also offers valuable insights that could be used to guide similar efforts in other developing countries. However, the researchers note that further research is needed to evaluate the model's effectiveness and adaptability in real-world settings.