Naltrexone Helps Women Quit Smoking

October 26, 2006

Depade (naltrexone), an opiate blocker, helps women to quit smoking when used in combination with nicotine patches and behavior therapy, according to a new study. However, the drug did not provide the same benefit in men.

Study results showed Naltrexone used in combination therapy raised women’s quit-rate by 50% - and decreased the average first-month weight-gain typical of women who quit, according to researchers Andrea King, PhD, of the University of Chicago, and colleagues.

The study was reported in the October issue of Nicotine & Tobacco Research and summarized by MedPage Today on October 9.

"Women have historically had less success than men in giving up cigarettes. In this small study, naltrexone seems to have closed that gap," Dr King reportedly said.

Despite evidence that Naltrexone helps control opiate addictions (such as heroine) and decrease the likelihood of relapse in people with alcoholism. To date, report on naltrexone’s effectiveness in reducing nicotine withdrawal symptoms have been inconsistent.

Clinical Trial

The researchers conducted a placebo-controlled trial in 110 adult smokers (women and men), recruited through local advertising.

Participants received a combination of behavior counseling (1h/week x 6 weeks) plus a nicotine patch (x 4 weeks: 21mg/first two weeks; 14mg/ third week; 7mg/ fourth week) plus randomly assigned placebo or Naltrexone (starting dose: 25mg daily/three days before quit-date, then 50mg/day from quit-date through another eight weeks).

Smoking cessation was defined as: "not smoking even a puff daily for one week and not smoking even a puff at least one day in each of two consecutive weeks at any point in the trial."

Results

Despite no significant difference in quit-rates between the Naltrexone and placebo groups overall, data breakdown by gender revealed Naltrexone helped raise women’s quit-rates to the level of men’s.

Among women receiving placebo, only 39% had quit smoking at eight weeks, versus 67% of men. However, almost equivalent numbers of women and men receiving Naltrexone were able to quit (58% and 62%, respectively).

"Further examination revealed that naltrexone significantly reduced men’s and women’s cessation-related weight gain and selectively reduced women’s urge to smoke to relieve negative affect and withdrawal," Dr King and colleagues wrote. Weight-gain among the 97 participants completing the first month averaged one pound for participants receiving Naltrexone, versus four pounds for participants receiving placebo.

Weight-gain has been shown to deter some people from quitting smoking. The researchers suggested that the relatively lower weight gain with naltrexone may be more important to women than to men.

"Although prior research is mixed on the role of opioid antagonism in smoking-related behaviors, this preliminary study indicates that naltrexone may be beneficial as an adjunct to comprehensive smoking cessation treatment (counseling and patch), particularly for female smokers," they wrote.

The researchers acknowledged that the study was preliminary and too small to make in-depth analyses of various aspects influencing quitting smoking or gaining weight. They also reported a relapse rate – at week 24 of the study, just over one-third of participants receiving Naltrexone were still smoke-free.

Sources:
Opiate Blocker Helps Women Stop Smoking, MedPage Today, October 09, 2006.
Efficacy of naltrexone in smoking cessation: A preliminary study and an examination of sex differences. King A et al, Nicotine & Tobacco Research, volume 8(5), pages 671-682.

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