One in five people who smoke also drink heavily, but they show worse outcomes than non-heavy drinkers in quitting smoking and are often excluded from smoking cessation trials.
The study was published in JAMA Network Open.
Knowing how challenging it can be to quit smoking, Andrea King, PhD, Professor of Psychiatry and Behavioral Neuroscience at the University of Chicago, wanted to find a treatment that could help smokers to quit, particularly those who would describe themselves as heavy drinkers.
It may be easy to dismiss heavy drinking and smoking behaviors as “bad habits,” but there are biological mechanisms that tie the two tightly together.
To this point, King’s past research has shown that the higher the alcohol consumption, the more intense the urge to smoke, and that alcohol acutely activates brain reward pathways when smokers were shown images of smoking.
“Instead of blaming them, I thought, if we could find treatments that could help them, that would really help because they are at risk for health consequences that are worse than using either substance alone,” she said.
King set out to test whether smokers who also drink heavily could be helped through a combination treatment, using two drug therapies together instead of just one. She wondered whether combining treatments that are known to work well would help with smoking cessation for this group.
During the 12-week study, King and her collaborators gave 122 smokers who were also heavy drinkers either nicotine replacement therapy (in the form of the nicotine patch) in combination with the smoking cessation drug varenicline, or in combination with placebo. During weeks nine to 12, the participants were asked to report whether they were abstaining from smoking. Those individual reports were confirmed by a lab test administered during week 12.
The results showed that the combination treatment of nicotine replacement and varenicline was indeed more effective for smoking cessation, with 44.3 per cent of participants abstaining from smoking through the last weeks of the study.
In contrast, less than a 27.9 per cent of the participants who received nicotine replacement combined with placebo had still quit at the end of the study. The combination treatment was also well tolerated by most participants and did not produce any severe side effects.
King and her colleagues were surprised to find that participants from both groups in the study also reduced their rates of drinking.
At the beginning of the study, male participants drank more than 14 drinks per week and female participants drank more than seven drinks per week. All had at least one heavy drinking day (at least four to five drinks in a day) per week.
But by the end of the study, weekly drinking days for participants decreased by 25 per cent. Surprisingly, this was true in both the combination treatment and the nicotine replacement-alone groups. Neither varenicline nor nicotine replacement had been shown to decrease drinking rates in smokers before, so it was unclear why the study participants reduced their drinking during the study.
In light of these findings, King says that she wants to see drinking addressed more frequently in treatment programs for smokers who are trying to quit.
For example, smoking cessation treatment could be tailored to heavy drinkers by administering a combination treatment like varenicline and nicotine replacement therapy to provide extra support. Treatment providers could also inform patients of how their drinking habits might affect their efforts to quit smoking, which could help participants to struggle less with smoking and/or drink less for better health outcomes.
“Patients listen when we say, ‘This is what we know from a science base and this could really help you,'” she said. “It’s so important to identify those effective treatment combinations and be able to tell patients what works and help them along this important journey.”