Life / Health

New anti-smoking drug Naltrexone has his and hers effects

It’s a tobacco cessation drug with very strange his and hers effects.

A drug that can double the chances a man will win his killer weed battle has no apparent effects on a woman’s ability to quit, a new study shows.

But the medication known as Naltrexone can help women dramatically curb the weight gain associated with ditching cigarettes while having no effects on a male quitter’s battle with the post-smoke bulge, according to University of Chicago research.

“It was very confusing to us,” says Andrea King, a clinical psychologist and addiction expert at the school.

“But there are distinct benefits for men and women.”

An opioid blocker, Naltrexone itself has long been approved for use in combating heroin and alcohol addiction.

And as it’s already in the medical armament, doctors can prescribe it immediately for smokers – albeit for starkly different, sex-based reasons, King says.

The study of 700 smokers — all of them using tobacco patches — showed those men using the drug increased their chances of quitting from 17 to 30 per cent after a 12-week trial.

For women, however, the increase in quit rates were negligible.

Those female subjects who’d taken Naltrexone, however, had gained an average of just over one kilogram after at the three month trial. Those who did not get the drug put on more than double that amount, averaging more than two kilograms in gained girth.

And the weight control effects persisted for a year, though the differences diminished over the months. After six months, for example the Naltrexone women had gained 40 per cent less weight on average than their counterparts.

That dropped to 20 per cent after a year — 5.9 versus 7.4 kilograms.

Still, King says those types of weight-control effects have never been seen in an anti-smoking drug before and that Naltrexone could be used by women to stem post-smoking gains.

And with weight worries a key reason many women don’t even attempt to quit, such a drug could provide female smokers with a strong incentive to try, King says.

“There have been some other treatments that have delayed the weight gain,” she says.

“But this is the first medication I’m aware that’s shown the effects even months and months after you’ve been off of it.”

On the men’s side, King says the quitting advantage that Naltrexone appears to offer rivals those of the well known cessation medications Zyban and Wellbutrin and that it could be added to that arsenal in the future.

But men experienced little or no weight control benefits from the drug.

King says researchers have no idea why the drug shows such pronounced gender differences, but speculate there may be hormonal or psychological factors at play.

The study appears in the December issue of the journal Biological Psychiatry

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