近日，FDA批准了戒烟新药Chantix，该药为片剂，它的活性成分为varenicline tartrate，是一种新分子实体。因为该药会为公众健康带来较大的益处，因此它获得了FDA的优先审批权。
Chantix作用于人体脑部受尼古丁影响的部位，并通过两种方式帮助吸烟人士戒烟：即在一定程度上发挥与尼古丁相似的作用以缓解在戒烟过程中出现的戒断症状；并且在这些人戒烟后复吸时阻断烟草所含尼古丁对人体的作用。
Chantix的戒烟效果在六个临床试验中得到了证实，与安慰剂对照组相比，该药的戒烟效果更佳。参加临床试验的受试者平均烟龄达25年，每天平均吸21根烟。
Chantix的疗程为12周，戒烟成功后，还需继续用药12周以保证长期的戒烟效果。它的副作用包括恶心呕吐、头痛、肠胃气胀、失眠多梦和味觉减退。
批准日期：2006年9月1日  公司：辉瑞公司
CHANTIX（伐尼克兰[varenicline]）片剂,供口服使用
美国最初批准：2006年
警告：
严重的神经病学事件请参见完整的BOXED警告的完整预定信息。
在服用CHANTIX的患者中报告了严重的神经精神事件。
告知患者和护理人员患者应立即停止服用CHANTIX并立即联系医务人员，如果观察到患者出现躁动，敌意，情绪低落或行为或思维变化，或患者出现自杀意念或自杀服用CHANTIX时或停用CHANTIX后不久的行为。
权衡CHANTIX对其使用效益的风险。与使用安慰剂治疗相比，CHANTIX已被证明可以增加戒烟的可能性长达一年。戒烟带来的健康益处是即时和实质性的。
最近的重大变化
禁忌症：4/2010
已知的超敏反应
作用机制
伐尼克兰在α4β2神经元烟碱乙酰胆碱受体上以高亲和力和选择性结合。 CHANTIX在戒烟中的功效被认为是伐尼克兰在烟碱受体的α4β2亚型上的活性的结果，其中其结合产生激动剂活性，同时防止尼古丁与这些受体结合。
体外电生理学研究和体内神经化学研究表明，伐尼克兰与α4β2神经元烟碱型乙酰胆碱受体结合并刺激受体介导的活性，但其水平明显低于尼古丁。伐尼克兰阻断尼古丁激活α4β2受体的能力，从而刺激中枢神经中脑边缘多巴胺系统，被认为是吸烟时经历的强化和奖励的神经元机制。伐尼克兰具有高选择性，对α4β2受体的抑制作用强于其他常见的烟碱受体（> 500倍α3β4，> 3500倍α7，> 20,000倍α1βγδ），或非烟碱受体和转运蛋白（> 2000倍） ）。伐尼克兰还以5-HT3受体的中等亲和力（Ki = 350nM）结合。
适应症和用法
CHANTIX是一种烟碱受体部分激动剂，用于辅助戒烟治疗。
剂量和给药
在患者设定的日期前一周开始CHANTIX给药以戒烟。
开始一周：第1-3天每天一次0.5mg，第4-7天每天两次0.5mg。
持续数周：每天两次，每次1毫克，共12周。
建议成功戒烟者再接受12周的治疗，以增加长期戒烟的可能性。
肾功能损害：减少严重肾功能不全患者的剂量（估计肌酐清除率<30 mL / min）。
考虑不能​​耐受不良反应的患者的剂量减少。
对于未能戒烟或复发的人，建议采取另一种治疗尝试，以解决导致尝试失败的因素。
为患者提供适当的教育材料和咨询，以支持戒烟尝试。
剂量形式和强度
片剂：0.5mg和1mg。
禁忌症
对CHANTIX有严重超敏反应或皮肤反应的病史。
警告和注意事项
血管性水肿和过敏反应：已报道此类反应，包括血管性水肿，不经常危及生命。指导患者停止使用CHANTIX，并在症状出现时立即就医。
严重的皮肤反应：据报道，罕见的，可能危及生命的皮肤反应。指导患者停止使用CHANTIX并在首次出现皮疹和粘膜病变时立即联系医务人员。
意外伤害：已报告意外伤害（例如交通事故）。指导患者使用谨慎驾驶或操作机器，直到他们知道CHANTIX如何影响他们。
恶心：恶心是最常见的不良反应（发病率高达30％）。减少剂量可能会有所帮助。
不良反应
最常见的不良反应（>5％和安慰剂治疗患者中的两倍）是恶心，异常（例如，生动，异常或奇怪）的梦，便秘，胃肠胀气和呕吐。
要报告疑似不良反应，请致电1-800-438-1985联系辉瑞公司，或致电1-800-FDA-1088或www.fda.gov/medwatch联系FDA。
药物相互作用
其他戒烟疗法：安全性和疗效与其他戒烟疗法相结合尚未确定。伐尼克兰和透皮尼古丁的共同给药导致由于不良事件导致的高停药率。
戒烟的影响：某些药物的药代动力学或药效学可能因CHANTIX戒烟而改变，需要调整剂量。
用于特定人群
怀孕：只有在潜在的益处证明对胎儿有潜在风险的情况下，才应在怀孕期间使用CHANTIX。
护理母亲：考虑到药物对母亲的重要性，停止使用药物或护理。
儿科用途：未建立安全性和有效性。
肾功能损害：严重肾功能损害需要调整剂量。
包装提供/存储和处理
CHANTIX提供两种强度的口服给药：0.5毫克胶囊双凸面，白色至灰白色，薄膜包衣片，一面用“Pfizer”压印，另一面用“CHX 0.5”和1毫克胶囊双凸面， 浅蓝色薄膜包衣片的一面是“Pfizer”，另一侧是“CHX 1.0”。 CHANTIX提供以下包装配置：
CHANTIX 0.5MG TAB 56 VARENICLINE TARTRATE PFIZER PHARM 69046856 
CHANTIX 1MG TAB 56 VARENICLINE TARTRATE PFIZER PHARM 69046956 
CHANTIX CONT MTH PK 1MG TAB 56 VARENICLINE TARTRATE PFIZER PHARM 69046903
CHANTIX STRT MTH PK TAB 53 VARENICLINE TARTRATE PFIZER PHARM 69047103
储存在25ºC（77ºF）; 允许偏移15-30ºC（59-86ºF）（参见USP受控室温）。
完整说明资料附件：
https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=826c77fa-d8b2-48df-8028-720b15912d92 。
Chantix ™
Chantix (varenicline) is the latest prescription medication designed to help adults quit smoking. It is also sold under the name Champix in Canada, Europe and other countries. Chantix is not a nicotine replacement therapy (NRT) product like the nicotine patch or nicotine gum that have been on the market for many years. Instead, Chantix is believed to work by blocking nicotine from reaching the receptors in the brain that are normally associated with cravings and addiction to nicotine. In clinical studies, patients using Chantix reported that their urge to smoke was reduced. In some of those same studies, as high as 44% of patients using Chantix abstained from smoking.
How does Chantix work?
To understand the way Chantix works, it’s important to understand how nicotine works.
Nicotine affects the brain. That’s one reason why it is so addictive. Nicotine enters the body and travels to the brain where it attaches itself to tiny receptors. This tells a different part of the brain to release dopamine, a neurotransmitter commonly associated with the pleasure response in the brain. The feelings of enjoyment provided by dopamine reinforce behaviors and motivate individuals to proactively perform certain activities, such as smoking.
When dopamine levels quickly drop, smokers often feel bad and experience cravings for another cigarette.
What Chantix does is attach to the same nicotine receptors, preventing dopamine release. Thus, while smoking introduces nicotine into the body, the nicotine is unable to cause dopamine release. No dopamine, no pleasure, no desire for more nicotine.
Since Chantix is attached to the nicotine receptors, there is some stimulation, but at much lower levels than that caused by nicotine. The stimulation “stays on” all the time since Chantix is taken daily for an extended period of time, creating a shield from the roller coaster ride of nicotine addiction. Smokers have fewer cravings and experience less of the typical withdrawal symptoms they might experience without the use of Chantix.
Clinical Trials of Chantix
Chantix was tested and studied in six separate trials, involving 3659 smokers who smoked 10 or more cigarettes per day.
Two of the studies were double-blind, meaning that neither the personnel administering the medication, nor the patients knew which medication each patient was receiving. This type of study removes any bias that might creep in when one or more parties has preconceived expectations about a particular pill. The two studies compared the use of placebo (sugar) pills, Zyban (bupropion, another prescription smoking cessation medication) and Chantix. Both studies had nearly identical results, with 44% of patients treated with Chantix abstaining from smoking during weeks 9 through 12 of the study. Patients given the Zyban had an abstinence rate of 30%. Patients treated with the placebo had abstinence rates of 17% in the first study and 18% in the second.
Five of the six studies examined long-term abstinence rates, with 40 weeks of follow-up. In all of the studies, patients treated with Chantix were more likely to remain smoke-free after the treatment ended than those treated with the placebo or Zyban.
A sixth study was conducted to determine if patients would benefit from an additional 12 weeks of treatment after the initial 12 week treatment period. The study found that patients who used Chantix for the additional 12 weeks were more likely to abstain from smoking during the 12 week treatment period, and were more likely to remain smoke free after the treatment ended.
Chantix Side Effects
As with most prescription and non-prescription medication, Chantix may cause side effects.
Chantix patients have reported a variety of side effects including nausea, headache, sleep difficulties (insomnia, vivid or strange dreams), constipation and gas. If these symptoms persist or if they bother you, let you doctor know.
Other more serious side effects such as suicidal thoughts, depression and behavioral changes have been reported as well. It’s important to report these symptoms to your doctor. Your family or others around you may notice these effects before you notice them yourself.
Before taking Chantix, tell your doctor about any history of depression or other mental health problems, since these may worsen when taking Chantix.
Use caution while driving or operating machinery until you know how Chantix may affect you.
Chantix should not be taken with other quit smoking medications.
If you have a kidney disorder or receive dialysis, you may need a lower dose of Chantix.
If you are pregnant, plan to become pregnant, or if you take insulin, asthma medicines, or blood thinners, tell your doctor before you start taking Chantix.
Dosage Info
Smokers receiving a Chantix prescription should first set a quit date upon which they will completely stop smoking. They should begin taking Chantix one week prior to their quit date.
The pills should be taken after a meal, with a full glass of water.
The recommended dose of CHANTIX is 1 mg twice daily following a one week introduction to the medication:
Days 1 to 3: 0.5 mg once daily
Days 4 to 7: 0.5 mg twice daily
Day 8 to end of treatment: 1 mg twice daily
If the patient cannot tolerate any adverse effects of Chantix they may have their dose reduced temporarily or permanently.
Treatment with Chantix should be for 12 weeks. After the initial 12 weeks, patients who have remained smoke free may receive an additional 12 week treatment to increase long-term smoking abstinence.
Patients who are not able to successfully quit smoking during the initial 12 weeks of treatment, or who relapse after treatment, should be encouraged to try again once they have addressed the reason their first attempt was not successful.
As with most any smoking cessation method or product, Chantix users are more likely to quit smoking successfully if they are self-motivated to end their habit, and if they are given additional support and advice. Ask your doctor for their help and suggestions to make quitting easier and more successful.
Conclusion
While the results from Chantix are promising (up to 44% quit rate), it still won’t help every smoker to quit. Nothing, short of death, will force a smoker to end their habit. Sorry, but their is no magic pill. Influencing and changing the way your brain reacts to nicotine can improve your chances of quitting smoking permanently. But you must first want to quit, and be willing to stick it out, even if you experience some discomfort. Remember, too, that smoking is more than just a nicotine addiction. As a smoker, you have created a life that tends to revolve around your next cigarette. To quit, you’ll need to change and disrupt your routine, stop doing certain behaviors that tend to trigger a desire for a cigarette such as getting a drink at a bar, and perhaps most important, you must believe that you can actually quit smoking.
http://dailymed.nlm.nih.gov/dailymed/archives/fdaDrugInfo.cfm?archiveid=11345
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