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The recommended and maximum dose of Zyban is 300 mg/day given as 150 mg, twice daily. Dosing should begin at 150 mg/day for the first three days followed by an increase to the usual dose of 300 mg/day. Treatment should be initiated while the patient is still smoking and a target date for smoking cessation should be within the first two weeks of Zyban treatment. Zyban therapy should continue for 7 to 12 weeks, depending on the effect of the therapy. If the patient has not reduced smoking by the seventh week of Zyban therapy, it is unlikely that he/she will quit during that attempt and Zyban therapy should be disc
BETHESDA, M.D. -- May 11, 2006 -- The U.S. Food and Drug Administration (FDA) today approved Chantix (varenicline tartrate) tablets, to help cigarette smokers stop smoking. The active ingredient in Chantix (varenicline tartrate) is a new molecular entity that received a priority FDA review because of its significant potential benefit to public health. Chantix acts at sites in the brain affected by nicotine and may help those who wish to give up smoking in two ways: by providing some nicotine effects to ease the withdrawal symptoms and by blocking the effects of nicotine from cigarettes if they resume smoking. "Tobacco use, particularly cigarette smoking, is the single most preventable cause of death in the United States and is responsible for a growing list of cancers as well as chronic diseases including those of the lung and heart," said Scott Gottlieb, MD, Deputy Commissioner for Medical and Scientific Affairs. "The agency is committed to helping facilitate the development of products to help people quit smoking and improve their overall quality of life." According to the Centers for Disease Control and Prevention (CDC), an estimated 44.5 million adults in the United States smoke cigarettes and more than 8.6 million of them have at least one serious illness caused by smoking. "Cigarette smoking is a very difficult habit to break due in large part to nicotine dependence or addiction" said Dr. Steven Galson, Director of FDA's Center for Drug Evaluation and Research. "Chantix therapy has proven to be effective in smokers motivated to quit and will provide another tool for physicians to use for the millions of smokers who want to quit." The effectiveness of Chantix in smoking cessation was demonstrated in six clinical trials, which included a total of 3659 chronic cigarette smokers who were treated with varenicline. Five of the six studies were randomized, controlled clinical trials in which Chantix was shown to be superior to placebo in helping people quit smoking. These smokers had previously averaged 21 cigarettes a day for approximately 25 years. In two of the five placebo-controlled studies, Chantix-treated patients were also more successful in giving up smoking than patients treated with Zyban (bupropion). The approved course of Chantix treatment is 12 weeks. Patients who successfully quit smoking during Chantix treatment may continue with an additional 12 weeks of Chantix treatment to further increase the likelihood of long-term smoking cessation. In clinical trials, the most common adverse effects of Chantix were nausea, headache, vomiting, flatulence (gas), insomnia, abnormal dreams, and dysgeusia (change in taste perception). Chantix is manufactured and distributed by Pfizer, Inc., New York, NY. SOURCE: Food and Drug Administration
Chantix (varenicline) can be four times as effective in helping a smoker give up cigarettes successfully, according to a report in JAMA (Journal of the American Medical Association), 5 July. According to the report, which cites three studies, Chantix is twice as effective as Zyban (bupropion).
The chances of having a relapse during the first six months after giving up are significantly reduced when a smoker is on Chantix, according to one study.
Chantix was approved by the FDA in May, 2006.
All the studies were funded by the makers of Chantix, Pfizer. A JAMA editorial is sceptical of all the hype surrounding this new smoking cessation drug. Robert Klesges, University of Tennessee Health Science Center, Memphis, USA, says enthusiasm for a new smoking-cessation drug is always high when it first comes onto the market. Even though Chantix has better results than either a placebo or Zyban, this does not necessarily mean it is the holy grail for smoking addicts.
Chantix works in a different way from Zyban or nicotine-replacement therapies. Nicotine-replacement therapies give you a small dose of nicotine - the aim is to provide the smoker with his/her drug while he/she overcomes the enormous psychological problems that come with giving up. Zyban undermines the reuptake of addiction-linked brain chemicals by neurons - dopamanine and norepinephrine. Chantix makes the patient produce more dopamine, which is supposed to help lower the cravings - at the same time brain cell receptors that help perpetuate addiction are blocked.
One study included 1,025 volunteers, all of them smokers who wanted to quit. Chantix, Zyban and a placebo were compared. The study lasted one year. Here are some facts from that study:
-- 44% of those on Chantix were not smoking at 12 weeks
-- 29.5%% of those on Zyban were not smoking at 12 weeks
-- 18% of those on a placebo were not smoking at 12 weeks
-- 22% of those on Chantix did not smoke from week 9 to 52
-- 16% of those on Zyban did not smoke from week 9 to 52
-- 8.4% of those on a placebo did not smoke from week 9 to 52
Another study, from the Unversity of Wisconsin included 1,027 volunteers, all of them smokers who wanted to quit. Results were almost the same as the ones above.
The third study involved people in seven countries - 1,900 smokers who wanted to quit. All of them took Chantix for the first 12 weeks, after which 1,236 (65%) were still not smoking. The 1,236 quitters were then divided into two groups: One group continued taking Chantix while the other took a placebo. This continued for another 12 weeks. At the end of the 24-week period:
-- 70.5% of those on Chantix were not smoking
-- 49.6% of those on a placebo were not smoking
After one year a significantly higher number of those who had been on Chantix were still not smoking compared to those on a placebo.
Chantix has some side effects, which were experienced by about one third of all the volunteers. They included nausea and strange dreams.
Scientists say that the Pfizer funded trials were carried out in ideal conditions for the participant - there was lots of support. Perhaps results may not be as encouraging when a patient gets a prescription from the doctor and is then left to his/own devices.
Even in this third study, which started with 1,900 volunteers, medication and plenty of support, only 871 were not smoking after 24 weeks - less than half.
”Varenicline, an a4 b2 Nicotinic Acetylcholine Receptor Partial Agonist, vs Sustained-Release Bupropion and Placebo for Smoking Cessation”
A Randomized Controlled Trial
Authors: David Gonzales, PhD; Stephen I. Rennard, MD; Mitchell Nides, PhD; Cheryl Oncken, MD; Salomon Azoulay, MD; Clare B. Billing, MS; Eric J. Watsky, MD; Jason Gong, MD; Kathryn E. Williams, PhD; Karen R. Reeves, MD; for the Varenicline Phase 3 Study Group