DOCTORS have been asked to restrict the number of controversial anti-smoking pills given to patients because of safety fears.

GPs in Darlington are being urged to limit Zyban prescriptions after reports that some patients have been sharing the pills with friends.

Zyban should not be taken by patients with a range of medical conditions.

The move is designed to reduce the number of unused tablets which may be circulating.

A spokesman for Darlington Primary Care Group said that it was concerned that spare pills "may be used in a dangerous and unsupervised manner".

Zyban is a powerful drug which works by changing chemicals in the brain to prevent nicotine addiction.

It should not be taken by people with liver or kidney problems, epileptics or women who are pregnant or breastfeeding.

While the drug has been linked to at least 37 deaths and 5,350 reported side-effects, the Department of Health says that Zyban thas helped hundreds of thousands of people to give up smoking.

Although there is no official advice on restricting the number of pills, Darlington Primary Care Group has asked family doctors in the area to prescribe a maximum of 20 pills rather than the normal 28.

The move follows "concerns" about patients who do not complete the course and pass spare pills to contacts.

Dr John Canning, a Middlesbrough GP who is a member of the British Medical Association's national GP committee, said: "It is really quite worrying."

Smoker, Amanda Sinclair, 25, from Thornley, near Wheatley Hill, County Durham, blacked out after taking Zyban and is considering legal action.

She said she was horrified that people were passing on unwanted Zyban pills.

Medical negligence experts Alexander Harris, of Manchester, said they had been contacted by more than 40 smokers who had adverse side-effects after taking Zyban.

"It is extremely unwise to take someone else's medicine," a spokesman for Alex-ander Harris said.

A spokesman for the Department of Health said: "If a GP makes a clinical judgement it is entirely up to them. If they think people are at risk they are within their rights."