Compared to people who take one treatment, more people who take two common stop-smoking treatments have stopped smoking three and six months after starting treatment. But there’s no difference after twelve months.
Varenicline (brand name Champix) and bupropion (brand name Zyban) are two types of treatments that help people stop smoking. There are other treatments too, and doctors usually recommend people take the treatment that they prefer, and those that suits their needs and preferences.
Doctors usually recommend people only take one type of treatment at a time - either varenicline, bupropion, or one of the other treatments. This is because we don’t yet know if taking combinations of treatments works better than taking one on its own, and whether taking combination treatments in this way is safe.
To try and find out, researchers looked at 506 adults who smoked and wanted to stop. Roughly half the group was randomly chosen to take varenicline and bupropion, while the other half of the group took varenicline along with a placebo (dummy) treatment. Both groups had treatment for 12 weeks. The researchers recorded how many people in each group had stopped smoking after 12, 26, and 52 weeks, and how many people had unwanted side effects.
More people who took combination treatments stopped smoking for 12 and 26 weeks, but there was no difference between the groups after 52 weeks.
After 12 weeks, about 53 in 100 people who took combination treatments had stopped smoking compared to about 43 in 100 people in the varenicline-only group.
After 26 weeks, about 37 in 100 people in the combination group had stopped smoking compared with about 28 in 100 in the varenicline-only group.
After 52 weeks, about 31 in 100 people in the combination group and about 25 in 100 people in the varenicline only group had stopped smoking. (This difference wasn’t large enough to rule out the effect of chance.)
When the researchers looked for differences between the number of people in each group who had side effects, they found more people in the combination treatment group had anxiety or depression. About 10 in 100 people in the combination treatment group had anxiety or depression, compared with about 4 in 100 in the varenicline-only group.
There was also a difference in how much weight people in the two groups gained after 12 weeks of treatment. On average, people in the combination treatment group gained 1.1 kilograms, and people in the varenicline-only group gained 2.5 kilograms. But people in both groups had gained a similar amount of weight, on average, after 26 and 52 weeks.
How reliable is the research?
Giving different treatments to people in randomly chosen groups is usually a reliable way of comparing treatments. It’s worth noting that about one third of the participants dropped out during the study. We don’t know whether these people stopped smoking or not. However, the researchers argue that as roughly the same proportion of people dropped out from both groups, this may not have had that much of an effect on the results. This study was done in relatively healthy adults, with no major illnesses, so we can’t be sure if the results apply more generally.
To provide even greater transparency and choice, we are working on a number of other cookie-related enhancements. More information