Background: To address the problems related to drug resistance and medication safety, the rational drug use (RDU) policy has been implemented in Thailand since 2014. Theoretically, the policy was supposed to bring drastic changes to the way clinicians prescribe medications and its impacts on clinical practice, however, it has not yet been investigated. The study aimed to describe the experience of community health nurses with regard to the impact of RDU policy implementation on their practices. Methods: Focus group interviews and in-depth interviews with community nurses were conducted. Thematic analysis was performed. Results: Five themes emerged from the analysis, namely, (1) a welcome opportunity, (2) RDU as the quality of healthcare, (3) multidisciplinary collaboration, (4) reinventing productive interactions between nurses and patients, and (5) challenges over control of medications prescribed or purchased elsewhere. Conclusions: Implementing RDU in primary care provides opportunities for protecting individual patients and public health as well as safeguarding against professional prescription error. This can be made possible by adopting a systemic approach to changes. Additional educational and organizational support will optimize health professionals’ contribution to the implementation and hence optimal outcomes of this important policy.