Safe and rational prescribing is a fundamental component of effective healthcare delivery and responsible resource utilization. As the final stage of clinical decision-making, prescribing translates diagnosis into therapeutic action and therefore plays a critical role in determining patient outcomes. High-quality prescriptions must adhere to established clinical guidelines and formulary recommendations to ensure patient safety, reduce medication errors, and promote cost-effective treatment. Formularies serve as structured decision-support tools that guide clinicians toward evidence-based medication choices while minimizing variability in prescribing practices across healthcare settings. In the United Kingdom, prescribing decisions are largely informed by the British National Formulary (BNF) alongside local formularies developed by National Health Service (NHS) Trusts and Primary Care Organizations. These local formularies represent curated selections of approved medicines that reflect institutional priorities, population needs, and budgetary considerations. They also facilitate coordinated prescribing between primary and secondary care services. Auditing prescribing practices against formulary standards provides valuable insights into the quality of medication use, identifies deviations from recommended guidelines, and highlights opportunities for improving clinical practice. Evaluating formulary compliance in outpatient clinics is particularly important due to the high patient turnover and the diversity of medical conditions managed in these settings. Such assessments support quality assurance initiatives, strengthen medication governance, and contribute to the optimization of pharmacotherapy. Ultimately, systematic audits of prescribing patterns can enhance rational drug use, improve patient safety, and support sustainable healthcare systems.