Skin drug helps smokers

Drug may reduce nicotine craving

A drug developed to relieve symptoms of the skin disorder psoriasis might also help smokers to quit the habit, say researchers.

They have discovered that the psoriasis medication Methoxsalen can reduce smokers' craving for nicotine.

Methoxsalen is usually given in combination with intense ultraviolet light to patients with psoriasis, a chronic skin disorder characterised by reddish plaques covered with dry silvery scales and often severe itching.

Professor Edward Sellers and his team from the University of Toronto have discovered that the drug also acts to block an enzyme in the body that breaks down nicotine.

If you can slow the breakdown of nicotine, people will smoke less and get into a position where they can actually stop

Professor Edward Sellars, University of Toronto

Usually, the enzyme, CYP2A6, acts to remove half the amount of nicotine contained in a cigarette within an hour of it being smoked.

This means that the smoker will soon crave another cigarette to replenish nicotine levels.

Methoxsalen acts to slow down this process so that the craving for more cigarettes is reduced.

Professor Sellers said: "If you can slow the breakdown of nicotine, people will smoke less and get into a position where they can actually stop."

Big reduction

The Toronto study was conducted on only 12 people, who got just a single dose of the drug.

But the findings were impressive: the volunteers smoked 25% less after taking the drug.

In combination with a nicotine replacement treatment, such as the patch, the figure rose to as much as 50%.

The researchers now plan further studies to ensure that the drug is both effective in the longer term, and safe in high doses.

Professor Sellars said: "For it to be effective in smoking, we would have to give it chronically every day."

He is already working on a bigger study with about 30 smokers, which should be completed within a few months.

Clive Bates, director of the anti-smoking charity Action on Smoking and Health (ASH) said new drugs could complement existing treatments such as nicotine replacement therapy and the recently released drug Zyban.

Zyban works on receptors in the brain to reduce the craving for nicotine, but it cannot be prescribed for some patients, including those who are pregnant or taking anti-depressants.

"Any new approach to reducing nicotine addiction has got to be a good thing.

"It is too soon to know whether this drug might be useful, but potentially it might help people who cannot take the other drugs that are available, or it might be used in combination with other products."