Zyban linked to spike in UK adverse drug reactions

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Zyban linked to spike in UK adverse drug reactions

By Woodman

LONDON, Jun 27 (Reuters Health) - The number of suspected adverse drug

events being reported in the UK has shot up by over one third, mainly

because of GlaxoKline's smoking cessation drug Zyban, the Medicines

Control Agency (MCA) said on Wednesday.

The MCA's latest statistics show that 37% more so-called " yellow cards "

recording adverse reactions were received from January to April 2001

compared with the same period in 2000. The number of serious reports also

rose 16%.

" The main factor in the 37% increase is the large number of reports

associated with the smoking cessation aid, Zyban, " an MCA spokeswoman

explained in a statement to Reuters Health.

She pointed out that reporting for this drug only began in July 2000 and was

therefore not a factor at this time last year. However from January to April

2001 Zyban " accounted for 32% of all yellow cards. "

On May 31, 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 there had been over 5,000 adverse reports relating to Zyban,

including 40 deaths.

Today's statement makes clear that the number of reports of adverse

reactions that are received in association with a drug depends on many

factors, including the extent of use of the drug and the publicity

surrounding the drug.

" In addition, reporting tends to be high for newly introduced medicines.

Therefore, the number of reports received in association with Zyban is

expected to be high, as this

drug has been widely prescribed--at least 419,000 individuals have received

Zyban (in the UK)--and has been the subject of considerable public

interest. "

The spokeswoman said another reason for the high number of reports was that

doctors had been asked to report suspected adverse events as well as events

they felt were definitely linked to Zyban.

A GSK spokesman told Reuters Health that it was well known that Zyban is a

prescription-only medicine that must be taken appropriately and not by

patients with a history of seizures.

He said over five million people had taken the medication worldwide and

there had been huge usage in the UK. The rate of seizures seen was

consistent with the clinical trials' experience, he said, and the product

remained a very valuable medicine for quitting smoking.

The yellow card scheme was introduced in the UK after the Thalidomide

tragedy-a jump in the rate of severe birth defects in Europe in the 1950s

and 1960s that occurred when the sedative drug was taken by pregnant women.

The system is intended to pick up side effects of drugs that may not have

been seen during clinical trials. The cards are filled in by doctors and

other healthcare professionals and sent to regulators.