NEW HAVEN, Conn., Oct. 7 (UPI) — The smoking cessation drug varenicline, sold as Chantix, is more effective for women during the first year of treatment, before becoming equally effective for both men and women, according to a new study.
Other nicotine replacement therapies, and drugs such as bupropion, which is sold as Wellbutrin and Zyban, generally have lower quitting rates for women than men. Researchers said while they think nicotine receptor system in the brain may work differently for women than for men, they’re not entirely sure why varenicline would appear to even things out.
“Studies show that women have a harder time quitting smoking than men, even as quitting has shown greater benefits to women’s cardiovascular and respiratory health,” said Sherry McKee, a professor of psychiatry at Yale, in a press release. “With this first comprehensive analysis of sex differences in the effectiveness of this drug, now women and their healthcare providers can better decide how to successfully quit and live longer, healthier lives.”
Researchers analyzed 17 of the 43 clinical trials conducted with varenicline, which included 6,710 smokers — 34 percent of whom were women. Participants were randomly treated either with varenicline or a placebo, and monitored for 12 weeks. After treatment, researchers followed up with participants after 6 and 12 months.
Overall, 53 percent of both male and female participants taking varenicline had abstained from smoking after three months of treatment. When the Yale researchers factored in a lower effect from placebos with women, they found varenicline was 46 percent more effective than other treatments at helping women quit, and 31 percent more effective at maintaining complete abstinence after six months.
After one year, however, the researchers found the drug helped about the same amount of men and women quit smoking, which they do not yet completely understand.
“While it’s clear that sex differences in varenicline efficacy exist, we don’t yet know why varenicline is particularly effective for women,” McKee said. “This is the first demonstration that women compared to men have a preferred therapeutic response for a smoking cessation medication when considering short-term treatment outcomes and equal outcomes at one year. Varenicline appears to be particularly useful for reducing the sex disparity in smoking cessation rates.”
The study is published in Nicotine and Tobacco Research.