In a safety update posted on its Web site, the MCA reminded doctors that Zyban should not be prescribed to patients with a history of seizures, bulimia, anorexia nervosa, or those experiencing abrupt withdrawal from alcohol or benzodiazepines.
It added that the contribution of Zyban to the 57 deaths was «unproven» and that in most cases, the individuals underlying condition might have been responsible. It added that in 14 cases, patients were not taking Zyban at the time of death.
A GSK spokesman told APM-Reuters: «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 drug has been under close surveillance since it was re-launched for smoking cessation in mid 2000. An estimated 500,000 people have so far taken the drug in the UK where it accounts for a 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 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.
According to the MCA, Zyban is associated with a dose-related risk of seizure of approximately 0.1% per cent. It said 168 reports had been received in the UK of seizures suspected as being associated with the use of Zyban. 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.
