Pharmacogenomics (PGx) has revolutionized personalized medicine by empowering the tailoring of drug treatments based on individual genetic profiles. However, the complexity of drug response mechanisms necessitates the integration of additional biological and environmental factors. This article explores integrating epigenetics, nutrigenomics, microbiomes, protein interactions, exosomes, and metabolomics with PGx to enhance personalized medicine. In addition to discussing these scientific advancements, we examine the regulatory and ethical challenges of translating multi-omics into clinical practice, including considerations of data privacy, regulatory oversight, and equitable access. By framing these factors within the context of Medication Adherence, Medication Appropriateness, and Medication Adverse Events (MA), we aim to refine therapeutic strategies, improve drug efficacy, and minimize adverse effects, with the goal of improving personalized medicine. This approach has the potential to benefit patients, healthcare providers, payers, and the healthcare system as a whole by enabling more precise and effective treatments.