There is currently no reason to believe that patients taking Zyban have an increased risk of death

GlaxoSmithKline spokesman

In a notice published on its website, the MCA said: "There have been 57 reports of suspected adverse reactions to Zyban which have resulted in a fatal outcome.

"The contribution of Zyban to these fatal cases is unproven and in the majority of cases the individual's underlying condition may provide an alternative explanation.

"In 14 of these reports the individual was not taking Zyban at the time of their death."

Raised awareness

The MCA has received 6,975 reports of suspected adverse reactions to Zyban, including insomnia, rashes, headache, nausea, vomiting and depression.

Of those, 168 patients suffered seizures suspected as being associated with Zyban.

As with all new drugs, the safety of Zyban remains under close review

Medicines Control Agency spokesman

A spokesman for the MCA said the figures were an update to keep people aware of the position.

"As with all new drugs, the safety of Zyban remains under close review."

He added: "Comparing Zyban with other medicines, the proportion of Zyban reports that have fatal outcomes is much lower - less than 1%."

Doctors and pharmacists will be asked to continue reporting all suspected adverse reactions to the MCA and the Committee on Safety of Medicines, an expert advisory group.

A spokesman for pharmaceutical giant GlaxoSmithKline, which makes the drug, said: "Smoking-related disease claims 320 lives a day in the UK.

"There is currently no reason to believe that patients taking Zyban have an increased risk of death.

"There is no proven link with deaths and the medicine is used in patients who are already at risk because of smoking.

Clive Bates, of Action on Smoking and Health, told BBC News Online said: "Most of these people would have died anyway.

"It's important not to confuse deaths that happen while using the drug with deaths that happen because of using the drug."

He added that over 400,000 people have used Zyban.