2008年12月FDA批准了Prestwick公司用于治疗亨廷顿舞蹈病的药物Xenazine (丁苯那嗪)，这是首个在美国获准治疗该症的治疗药。它获准的依据是一项III期临床实验结果显示，这种具有选择性作用功能的多巴胺耗竭治疗药疗效显著，并且安全性和耐受性良好。
Prestwick表示丁苯那嗪将在一项经FDA批准的风险评估项目下进行销售，这个评估项目主要防止该药有可能导致的抑郁和自杀倾向等不良反应。此前，该药也已被指定为罕见病治疗药，它在美国具有7年的独家销售权。该药获准后在美国受到欢迎，当地约有3万名患者深受这种疾病的困扰。美国遗传性疾病基金会表示，舞蹈病不仅给患者带来不便，它还会严重影响患者在步行、说话、工作和看电视等各方面的能力。目前，该药已在其他14个国家通过批准，新近获准的国家包括荷兰、瑞典和瑞士。

药品名：丁苯那嗪片

主要成分：丁苯那嗪

适应症及用法：口服给药。服药不受进食影响。

治疗舞蹈病、投掷症以及其它运动机能亢进性疾病：

成人:初始量：12.5mg，每天2次，逐渐增加至12.5-25mg，每天3次。如果最大剂量用药7天仍病情没有改善，则用该药可无效。

老人:初始量：12.5mg/天，然后逐渐增加剂量。

口服给药

中重度迟缓性运动障碍：成人:初始量：12.5mg/天，根据反应增加剂量。

药物过量：症状：困倦，出汗，低血压，低体温。处理：支持和对症治疗。

禁忌：对本品过敏者禁用；禁用于哺乳期妇女。

注意事项：可加重帕金森病的症状。影响驾车和机械操作能力。妊娠期妇女慎用。

不良反应：锥体外系症状、帕金森综合征，极少数出现急性肌张力异常，其它常见的不良反应包括困倦、疲劳、紧张、焦虑、失眠、兴奋、精神混乱、流涎、体位性低血压、恶心、头晕、偏执、皮疹、性欲减退、阳痿。

严重不良反应:抗神经病药恶性综合征。

药品相互作用：在单胺氧化酶抑制剂（MAOI）治疗期间或停药后14天内，不能给予本药。本药可阻断利血平的作用。本药消弱左旋多巴的作用，导致帕金森病加重。本药与金刚烷胺、甲氧氯普胺或抗精神病药合用，增加发生椎体外系副作用的风险。

FDA妊娠分级：C级:动物研究证明药物对胎儿有危害性（致畸或胚胎死亡等），或尚无设对照的妊娠妇女研究，或尚未对妊娠妇女及动物进行研究。本类药物只有在权衡对孕妇的益处大于对胎儿的危害之后，方可使用。

药理毒理：丁苯那嗪通过耗竭大脑神经末梢内的多巴胺来发挥作用，主要用于控制运动功能障碍。

药代动力学：

吸收:口服后经胃肠道吸收差，且不稳定。

代谢:大部分经肝脏首过代谢作用还原为羟基丁苯那嗪。

排泄:以代谢物形式经尿液排泄

Indications and Usage

XENAZINE can increase the risk of depression and suicidal thoughts and behavior (suicidality) in patients with Huntington’s disease. Anyone considering the use of XENAZINE must balance the risks of depression and suicidality with the clinical need for control of choreiform movements. Close observation of patients for the emergence or worsening of depression, suicidality, or unusual changes in behavior should accompany therapy. Patients, their caregivers, and families should be informed of the risk of depression and suicidality and should be instructed to report behaviors of concern promptly to the treating physician.

Particular caution should be exercised in treating patients with a history of depression or prior suicide attempts or ideation, which are increased in frequency in Huntington’s disease. XENAZINE is contraindicated in patients who are actively suicidal, and in patients with untreated or inadequately treated depression.

XENAZINE is also contraindicated in patients who have impaired hepatic function or are taking monoamine oxidase inhibitors or reserpine. At least 20 days should elapse after stopping reserpine before starting XENAZINE.

The need for therapy should be evaluated on an ongoing basis with the patient’s doctor. XENAZINE should be titrated slowly over several weeks for a dose that is appropriate for each patient. Before a dose greater than 50 mg is administered, the patient’s CYP2D6 metabolizer status should be determined.

Neuroleptic malignant syndrome (NMS), akathisia, agitation, parkinsonism, dysphagia, and QT prolongation–related arrhythmias have been reported with use of XENAZINE. XENAZINE should not be used in combination with drugs known to prolong QTc (which in certain circumstances can lead to torsades de pointes and/or sudden death), in patients with congenital long QT syndrome, or in patients with a history of cardiac arrhythmias. A potentially irreversible syndrome of involuntary, dyskinetic movements called tardive dyskinesia (TD) may develop in patients treated with neuroleptic drugs.  If signs and symptoms of TD appear in a patient treated with XENAZINE, drug discontinuation should be considered.  Adverse reactions associated with XENAZINE, such as QTc prolongation, NMS, and extrapyramidal disorders, may be exaggerated by concomitant use of dopamine antagonists.

XENAZINE elevates serum prolactin concentrations. Xenazine may induce sedation and somnolence (sleepiness or drowsiness) and may impair the ability to drive or operate dangerous machinery.

Some adverse events such as depression, fatigue, insomnia, sedation/somnolence, parkinsonism, and akathisia may be dose-dependent. If the adverse effect does not resolve or decrease, consideration should be given to lowering or discontinuing XENAZINE. The most commonly reported adverse events with XENAZINE compared to placebo were sedation/somnolence (31% vs 3%), fatigue (22% vs 13%), insomnia (22% vs 0%), depression (19% vs 0%), akathisia (19% vs 0%), anxiety (15% vs 3%), and nausea (13% vs 7%).

For more information, please see full Prescribing Information, including Boxed Warning, or go to www.xenazineusa.com.