Azathioprine（Imuran®）是一個抗代謝性免疫抑制劑，臨床上常作為治療全身性紅斑性狼瘡、重度風濕性關節炎、腎臟移植手術防止排斥之藥物。Azathioprine引起骨髓抑制的可能性與劑量相關，且此不良反應是可逆的，通常以白血球減少症顯現，尤其是腎移植及風濕性關節炎病患為高危險群，發生率分別為50%和28%；偶而也會出現貧血及血小板減少症，但引起泛血球減少症（pancytopenia）之機率則小於1%。
本文將探討一位全身性紅斑性狼瘡病患服用azathioprine 導致泛血球減少症之個案。病患在使用azathioprine六天後其白血球、紅血球及血小板之數值，即有逐漸下降之趨勢，且在停藥一週後，情況更加惡化，隨後介入治療，並於停藥兩週後情況好轉。
本文藉由文獻回顧，探討azathioprine引發泛血球減少症之機轉、進展及治療；並提醒處方者為達到理想治療目的，除謹慎使用藥物外，亦需常規監測血液檢查才是理想防治之道。

Azathioprine, an immunosuppressant antimetabolite, is frequently used to treat systemic lupus erythematosus, severe rheumatoid arthritis and prevent rejection of renal transplant. Therapeutic use of azathioprine may be associated with a dose-related, generally reversible, depression of bone marrow function, most frequently expressed as leukopenia (renal transplant: >50%; RA: 28%), but also sometimes as anemia and thrombocytopenia. The incidence of pancytopenia was less than 1%.
We described a patient with systemic lupus erythematosus who developed pancytopenia while receiving azathioprine 50mg daily. She had been treated with azathioprine for six days. Unfortunately, 6 days later, her complete blood counts decreased gradually. A week after discontinuation of azathioprine, the condition took a change for the worse. The counts of erythrocytes, leukocytes and platelets returned to normal in two weeks after discontinuation of azathioprine by supportive care.
This article discussed the pathology, mechanism and treatment by describing a case of azathioprine-induced pancytopenia and conducting a review of the literatures. In order to ensure patients’ drug safety, when azathioprine is prescribed, close clinical and laboratory monitoring are necessary.