LONDON (Reuters Health) - Fifty-seven people have died and nearly 7,000 have reported suspected adverse reactions in Britain after taking GlaxoSmithKline's smoking cessation drug Zyban (buproprion), according to new figures from the UK Medicines Control Agency (MCA).

In a safety update posted on its Web site, the agency reminded doctors not to prescribe Zyban to patients with a history of seizures, bulimia, anorexia nervosa or those experiencing abrupt withdrawal from alcohol or benzodiazepines.

The drug, which was originally licensed for treating depression, has been under close surveillance since it was relaunched for smoking cessation in mid-2000. An estimated 500,000 people have taken the drug so far in the UK, where it accounts for one third of all reported adverse drug reactions.

In its latest statement, the MCA said that up to 10 January 2002, a total of 6,975 reports of suspected adverse reactions to Zyban had been received in the UK.

It stressed reactions were ``not necessarily caused by the drug'' and might relate to other factors such as nicotine withdrawal, other illnesses or other medicines taken at the same time.

It added that the contribution of Zyban to the 57 deaths was ``unproven'' and that in most cases, the individual's underlying condition might have been responsible. In 14 cases, patients were not taking Zyban at the time of death, it noted.

A GlaxoSmithKline spokesperson told Reuters Health, ``There is currently no reason to believe that patients taking Zyban have an increased risk of death. The medicine is used in patients who are already at risk because of smoking. Smoking-related disease claims 320 lives a day.''

The firm said in October that Zyban sales had slumped 34% to 22 million (US$31.26 million) in the 3 months up to September 30 following media coverage of the reported deaths.

According to the MCA, Zyban is associated with a dose-related risk of seizure of approximately 0.1%. It said 168 reports had been received in the UK of seizures suspected of being associated with Zyban use. In half of the reports, patients had a history of seizures or seizure risk factors.

Last May, the UK Committee on Safety of Medicines issued a statement to doctors ordering changes to the starting dosages of Zyban and warning that patients at risk of a seizure should take the drug only if there were compelling reasons to do so.

It said at the time there had been over 5,000 adverse reports relating to Zyban, including 40 deaths.

French drug bulletin Prescrire--the ``bible'' for doctors on what to prescribe--concluded in October that Zyban had an unfavourable risk-to-benefit profile and recommended use of nicotine replacement therapy patches instead.

Prescrire said there was a 3% risk of hypersensitivity reactions with the drug and a 0.1% risk of convulsions, while no data was available on the dangers to patients with heart trouble.

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