Kennedy D T, Hayney M S, Lake K D
Drug Evaluation Unit, Hennepin County Medical Center, Minneapolis, MN 55407, USA.
Ann Pharmacother. 1996 Sep;30(9):951-4. doi: 10.1177/106002809603000906.
To report the price of a drug interaction between azathioprine and allopurinol that resulted in pancytopenia in a patient who had undergone a heart transplant.
A 63-year-old white man who received an orthotopic heart transplant in 1987 was hospitalized in June 1991 with a diagnosis of pancytopenia. His immunosuppressive medications on admission included cyclosporine 125 mg bid, azathioprine (AZA) 200 mg/d, and prednisone 2.5 mg/5 mg every other day. Six weeks prior to admission, the patient's local physician prescribed allopurinol for left wrist pain suspected to be gout. It was determined that the pancytopenia was caused by the drug interaction between AZA and allopurinol, both of which were withheld on admission. During hospitalization, the patient's white blood cell count dropped to 1.1 x 10(3)/mm3 with an absolute neutrophil count of less than 0.5 x 10(3)/mm3, a platelet count of less than 20 x 10(3)/mm3, and a hemoglobin of 3.7 g/dL. Four units of packed red blood cells were transfused and regramostim (GM-CSF) therapy was begun on hospital day 3 to speed the marrow recovery process. The patient was discharged on hospital day 8 and AZA, which had been withheld since admission, was restarted. The dosage was titrated to 200 mg/d over the following 2 weeks. The price of this patient's hospital stay was $13,042.
Not included in this price was the effect this drug interaction had on the patient's quality of life. Even after discharge from the hospital, it was estimated that it would take up to 3 months for the patient to fully recover his previous level of strength and functional capability. This interaction between AZA and allopurinol could easily have been avoided. Both the physician and the pharmacist missed this well-documented and potentially life-threatening drug interaction. Also, the patient failed to notify the transplant team when allopurinol was prescribed by his local physician. The importance of patient responsibility for medication therapy must be stressed to help avoid unnecessary drug interactions.
Undetected drug interactions can be life-threatening to patients as well as costly to the healthcare system. Drug interactions also can have a profound negative effect on the patients' quality of life, the price of which cannot be measured in dollars alone. It is vital that the physician, pharmacist, and patient work together to optimize therapeutic outcomes and avoid unnecessary drug interactions.
报告一例心脏移植患者因硫唑嘌呤与别嘌醇药物相互作用导致全血细胞减少的情况及代价。
一名63岁白人男性，1987年接受原位心脏移植，1991年6月因全血细胞减少入院。入院时其免疫抑制药物包括环孢素125毫克，每日两次；硫唑嘌呤（AZA）200毫克/天；泼尼松2.5毫克/5毫克，隔日一次。入院前六周，患者的当地医生因怀疑左腕疼痛为痛风而开具了别嘌醇。确定全血细胞减少是由AZA与别嘌醇的药物相互作用所致，入院时两者均停用。住院期间，患者白细胞计数降至1.1×10³/mm³，绝对中性粒细胞计数低于0.5×10³/mm³，血小板计数低于20×10³/mm³，血红蛋白为3.7克/分升。输注了4单位浓缩红细胞，并在住院第3天开始使用重组人粒细胞巨噬细胞集落刺激因子（GM-CSF）治疗以加速骨髓恢复过程。患者于住院第8天出院，自入院后一直停用的AZA重新开始使用。在接下来的2周内剂量滴定至200毫克/天。该患者此次住院费用为13,042美元。
该药物相互作用对患者生活质量的影响未包含在这一费用中。即使出院后，据估计患者也需要长达3个月的时间才能完全恢复到之前的体力和功能水平。AZA与别嘌醇之间的这种相互作用本可轻易避免。医生和药剂师都忽略了这一有充分记录且可能危及生命的药物相互作用。此外，当患者的当地医生开具别嘌醇时，患者未告知移植团队。必须强调患者在药物治疗中的责任，以帮助避免不必要的药物相互作用。
未被发现的药物相互作用对患者可能危及生命，对医疗系统而言成本也很高。药物相互作用还会对患者的生活质量产生深远的负面影响，而这种影响的代价无法仅用金钱来衡量。医生、药剂师和患者共同努力优化治疗效果并避免不必要的药物相互作用至关重要。
