Effect of Carbamazepine Initiation and Discontinuation on Antithrombotic Control in a Patient Receiving Warfarin: Case Report and Review of the Literature
Effect of Carbamazepine Initiation and Discontinuation on Antithrombotic Control in a Patient Receiving Warfarin: Case Report and Review of the Literature
复制标题
卡马西平开始和停药对接受华法林患者抗血栓控制的影响：病例报告和文献综述
作者：
R. Parrish;Danielle E. Pazdur;Philip O’Donnell
1例72岁的白人女性阵发性房颤患者接受华法林治疗5年，国际标准化比值（INR）稳定。她的牙医随后给她开了卡马西平200 mg/天的处方，以控制面部神经疼痛。在开始卡马西平治疗后约2周的下一次医生访视时，患者的INR从3.3降至1.3;她报告饮食或华法林剂量未发生变化，也未服用其他相互作用的药物。她的华法林剂量增加，大约2个月后INR恢复到2.0-3.0的目标范围。患者的INR保持稳定约6个月，直到她接受面部手术。在此期间，她的华法林停药5天，患者停止服用卡马西平，因为她没有疼痛。一个月后，她的INR从2.2增加到3.6。患者未发生任何血栓形成或出血事件。Warcantine通过细胞色素P450 2C 9进行肝脏代谢，卡马西平诱导这种同工酶。诱导华法林代谢需要增加华法林剂量以维持INR在治疗目标范围内。据我们所知，这是第一份报告记录的影响，卡马西平开始和停止在患者接受抗凝治疗华法林。对于服用华法林的患者，临床医生应在开始或停用卡马西平或改变剂量时密切监测INR。
A 72‐year‐old Caucasian woman with paroxysmal atrial fibrillation had been taking warfarin therapy for 5 years with a stable international normalized ratio (INR). Her dentist then prescribed carbamazepine 200 mg/day to control facial nerve pain. At her next physician visit about 2 weeks after the start of the carbamazepine, the patient's INR had dropped from 3.3 to 1.3; she reported no contributing changes in her diet or warfarin dosage, nor had she taken other interacting drugs. Her warfarin dosage was increased, and the INR returned to the target range of 2.0–3.0 approximately 2 months later. The patient's INR remained stable for approximately 6 more months, until she had facial surgery. During that time, her warfarin was discontinued for 5 days, and the patient had stopped taking the carbamazepine because she had no pain. One month later, her INR increased from 2.2 to 3.6. She did not experience any thrombotic or hemorrhagic episodes. Warfarin undergoes hepatic metabolism through cytochrome P450 2C9, and carbamazepine induces this isoenzyme. Inducing warfarin metabolism necessitates an increase in the warfarin dosage to maintain the INR in the therapeutic target range. To our knowledge, this is the first report documenting the effect of the carbamazepine initiation and discontinuation in a patient receiving anticoagulation therapy with warfarin. In patients taking warfarin, clinicians should monitor the INR closely when carbamazepine is started or discontinued, or when either dosage is changed.