In a tale of two anti-smoking drugs, two new aids to quitting smoking have emerged — one from the laboratory and one from the library.
Recently approved by the U.S. Food and Drug Administration, the new drug, varenicline tartrate, mimics the effects of nicotine to help kill cravings. According to two recent studies, it is at least as effective — and possibly significantly more so — than other currently used methods.
The most popular drugs used to help people quit smoking are nicotine replacement therapy (NRT) — gum, skin patches, tablets, nasal spray and inhalers — and the antidepressant drugs bupropion hydrochloride and nortriptyline hydrochloride. These have shown success rates varying from seven to 30 percent.
Mitchell Nides, Ph.D., of Los Angeles Clinical Trials, and colleagues with the Varenicline Study Group conducted a randomized, double-blind, placebo-controlled study to evaluate varenicline. Healthy smokers aged 18 to 65 years were randomly assigned to receive varenicline in various dosages, a placebo, or bupropion hydrochloride.
In the August 14/28 issue of the Archives of Internal Medicine, the authors report that varenicline, in combination with brief behavioral counseling, helped people quit in both the short and long term.
"Efficacy improved as the dose increased, with varenicline tartrate, 1 milligram twice daily, providing the highest rates of continuous abstinence across all treatment groups, including bupropion," they write. The four-week continuous quit rate for 1 milligram twice daily of varenicline was 48 percent; it was only 33.3 percent for bupropion hydrochloride and 17.1 percent for the placebo. Long-term quit rates (up to one year) were 14.4 percent for varenicline, 1 milligram twice daily, versus 4.9 percent for placebo.
Meanwhile, a review article in the same issue of the same journal describes a plant-derived drug, cytisine, that has been used to treat tobacco dependence in Eastern Europe for 40 years. While the drug appears to be effective, it is virtually unknown in most of the West.
Cytisine is an alkaloid found in a plant known as the golden rain tree, or Cytisus laburnum. It has been used for decades to help people quit smoking in Eastern European countries.
Jean-Francois Etter, Ph.D., M.P.H., of the University of Geneva, Switzerland, reviewed ten studies, all conducted in Bulgaria, Germany, Poland and Russia between 1967 and 2005.
"Research conducted during the past 40 years suggests that cytisine is effective for smoking cessation," Dr. Etter reports. "Thus, an apparently effective smoking cessation drug that has been used for decades in Germany and Eastern European countries remained unnoticed in other countries."
Most of the articles reviewed by Dr. Etter have never been cited in English language literature. Recent reviews of the efficacy of smoking cessation drugs omitted cytisine, and little research on the drug has been conducted in recent years.
Dr. Etter suggests the omission may be explained because studies on the efficacy of cytisine were not published in English and because the available research is based on studies that do not meet current scientific standards.
"An apparently effective treatment for the first avoidable cause of death in developed countries remained largely unnoticed, despite research published during the past 40 years," he concludes. "How many other effective drugs are there for which efficacy remained unnoticed because existing trials were not published in English in Western countries?"