Smoking Cessation Drugs Can Help Smokers Quit Weeks Beyond Their Target Quit Dates

02/04/08  Portland, Ore

Smokers, clinicians should not be discouraged or discontinue cessation medication when success is not immediate

An Oregon Health & Science University researcher has found smokers taking cessation drugs who are unable to quit in the first few weeks of treatment can quit weeks later if they continue taking the medication. Gonzales and colleagues will present findings this week at the annual meeting of the Society for Research on Nicotine and Tobacco in Austin, Texas.

"Our recent analysis shows smokers and clinicians should not be discouraged when total abstinence is not achieved in the first weeks of treatment with smoking cessation medications," said David Gonzales, Ph.D., lead author, director of the OHSU Smoking Cessation Center, and clinical investigator in medicine (pulmonary and critical care medicine), OHSU School of Medicine. "We found that quitting smoking was a dynamic process that was immediate for some, but delayed, taking several weeks, for others who took varenicline or bupropion."

To reach this conclusion, Gonzales and colleagues analyzed pooled data from two pivotal multicenter Phase III clinical trials that tested the efficacy of the smoking cessation drug varenicline (marketed as Chantix) versus bupropion (marketed as Zyban or Wellbutrin), or placebo. Gonzales was lead investigator for one of these studies; both of the studies were published in the July 5, 2006, issue of JAMA (Journal of the American Medical Association).

In the JAMA studies, Gonzales and researchers at 19 sites nationwide evaluated 1,025 smokers from June 2003 to April 2005 and found the non-nicotine drug varenicline to be more effective than bupropion or placebo in helping smokers quit and remain continuously abstinent from smoking for the last four weeks of drug treatment. But these studies did not look at quitting patterns for smokers taking varenicline over the 12 weeks of treatment. No study ever has.

Traditionally, clinicians and smokers have expected fairly immediate positive results from smoking cessation medications, according to Gonzales. "If smokers on medication don't quit in the first week or two following their target quit date, clinicians often will instruct their patients to discontinue their medication. Clinicians consider this a failed attempt," said Gonzales.

Smokers also often expect immediate results and may decide to stop taking their medication if they don't quit in a week or two, Gonzales explained.

With this in mind, Gonzales and colleagues endeavored to learn whether smokers taking varenicline, bupropion or placebo who failed to quit on their target quit date (beginning of second week of treatment) but who continued to take their medication would be able to quit  and stay quit by the last four weeks of treatment (weeks nine through 12).

In their recent analysis, the researchers found that smokers who achieved continuous abstinence for weeks nine through 12 had two distinct patterns of quitting; immediate quitting (quit on their target date) and delayed quitting (failed to quit on their target quit date, but quit later). There was a higher percentage of "immediate quitters" in those treated with varenicline (24.1 percent) versus bupropion (18.1 percent) and placebo (10.2 percent), and a higher percentage of "delayed quitters" for varenicline (20.1 percent) versus bupropion (11.7 percent) and placebo (7.5 percent).

These data suggest that quitting is a dynamic process and if smokers are encouraged and supported during treatment with varenicline or bupropion, they can quit over a period of weeks, not only quit on their target quit day, and clinicians should consider continuing to encourage their patients to stay on their medications beyond the first weeks of treatment even if they are unable to quit immediately.

Another important implication from this analysis, Gonzales explained, is that clinicians who don't encourage smokers unable to quit on their target quit date to continue taking their medication and to keep trying to quit, could inadvertently contribute to lost opportunities for nearly one-half of those who could quit if they provided such support.

The study participants evaluated for the 2006 JAMA studies and Gonzales and colleagues' subsequent 2007 Society for Research on Nicotine and Tobacco presentation were aged 18 to 75 and had smoked 10 or more cigarettes a day with fewer than three months of smoking abstinence during the past year. Participants had been randomly assigned to receive brief counseling plus either varenicline twice per day, bupropion twice per day or a placebo orally for 12 weeks, with 40 weeks of non-drug follow-up.

For more information on Gonzales' 2006 JAMA article, visit:

Gonzales has received research contracts from Pfizer, Sanofi-Aventis, Glaxo-SmithKline, Nabi Biopharmaceuticals and Addex Pharmaceuticals; consulting fees and honoraria from Pfizer,Sanofi-Aventis and GlaxoSmithKline; and owns five share of Pfizer stock.