Nearly one in five smokers offered help in kicking the habit while visiting their doctorâ??s office for a check-up will make a serious attempt to quit, a new study shows. And in this “real world” setting, the most effective smoking cessation drug therapy was a combination of bupropion SR (a sustained-release form of Zyban) and nicotine lozenges, Dr. Stevens S. Smith of the University of Wisconsin School of Medicine and Public Health in Madison and colleagues found.