新型口服抗凝血藥品（novel oral anticoagulants，NOACs)如rivaroxaban或dabigatran經臨床試驗證 實具有如warfarin能有效地預防心房纖維顫動病人發生中風的療效。然而，目前研究指出NOACs相較於 warfarin有較高的腾胃道出血風險。本研究之目的為分析台灣不良反應通報案例中與rivaroxaban與 dabigatran相關之出血風險，並進一步分析案例是否併有可能增加出血的危險因子。結果顯示使用NOACs 最常見的出血部位為腸胃道出血，且許多個案本身併有可能增加出血的危險因子，如高齡、腎功能不全 者或併用容易出血的藥品。因此本研究建議醫療照護人員於臨床使用NOACs時，對本身已具有會增加出 血危險因子的病人應定期監測腎功能並謹慎地做劑量調整，以減少藥品相關之出血不良反應。

In clinical trials, novel oral anticoagulants (NOACs) have proven to be as effective as warfarin for stroke prevention in patients with atrial fibrillation. However, most meta-analyses of phase III randomized controlled trials and observational studies have shown a higher incidence of gastrointestinal bleeding among NOACs than warfarin users in patients with atrial fibrillation. Using reporting cases from Taiwan’s National Adverse Drug Reaction Reporting System, the objective of this study was to examine hemorrhagic events associated with associated with two NOACs: rivaroxaban and dabigatran. Risk factors for hemorrhagic events among these cases were further explored. We found gastrointestinal hemorrhage was the most frequently reported bleeding site associated with rivaroxaban and dabigatran uses. In addition, our study identified several risk factors associated with NOACs-related hemorrhagic events, such as older age, impaired renal function or concomitant use of drugs with potential bleeding risk. Therefore, close monitoring of renal function and dosage adjustment for those with risk factors are suggested to reduce NOACs-associated hemorrhagic events.