目的：PRN藥囑為病人「需要時使用」，不需要常規給與的藥品。若缺乏明確適應症、間隔時間、給藥劑量是潛在的病人安全問題。為提升用藥安全，創建門急診PRN藥囑規範勢在必行。方法：運用品管圈活動提升門急診PRN藥囑完整率，選定四大掌握項目：PRN處方開立規範、PRN藥囑輸入介面、人為輸入差異、PRN藥囑完整性檢核，進而挖掘攻堅點，擬訂方策。目標設定為提升門急診PRN藥囑完整率達92.8%。結果：改善前門急診PRN藥囑完整率為63.9%，目標值為92.8%，改善後增加至93.2%，目標達成率101.4%，進步率45.9%。結論：門急診PRN處方的用藥安全議題，除了仰賴資訊界面優化與檢核把關外，也需於新進人員、持續教育中落實宣導提升以內化醫療人員的認知，共同提升醫療品質。

Objective: Pro Re Nata (PRN) medication orders are used for drugs that are to be taken “as needed” by the patient and do not require routine administration. They lack clear indications, intervals, and doses, posing potential safety risks. To enhance medication safety, establishing a standardized outpatient PRN medication order is imperative. Methods: To improve the completeness rate of PRN prescriptions in outpatient settings, quality control circle activities were employed. Four main areas were selected for intervene: regulations governing PRN prescriptions, software interfaces for entering PRN medication orders, discrepancies in human input, and completeness checks for PRN medication orders. Targeted strategies will then be developed to address these concerns, with an aim to improve the incompleteness rate by 80%. Results: Prior to the intervention, the completeness rate of PRN medication orders in outpatient emergency cases was 63.9%, with a target rate of 92.8%. After the implementation of improvements, the completeness rate increased to 93.2%, with a target achievement rate of 101.4%, an improvement rate of 45.9%. Conclusion: In addition to the optimization of the information interface and gatekeeping, the awareness of medical staff, particularly newcomers, should be enhanced, and continuous education should be promoted to enhance the overall quality of medical care.