Millions affected by US ban on slimming pills

The booming market for pills to tackle obesity was dealt a severe blow yesterday after reports of damaging health effects led to the withdrawal of the most widely used drugs.

Jeremy Laurance, Health Editor, reports on how the decision was reached.

Two of the most popular slimming pills, taken by millions of people, were withdrawn world-wide yesterday after US reports linked them with heart problems in some patients. The UK Committee on Safety of Medicines advised patients using the drugs, dexfenfluramine (sold in the UK as Adifax) and fenfluramine (Ponderax) to contact their doctors but said there had been no reports of detrimental effects linked with the drugs in this country.

Diet pills have become a craze in America and their use has been growing in the UK. Fenfluramine is half of the diet drug combination called fen- phen, for which 18 million prescriptions were written in the US last year.

The other half, phentermine, is not affected by the withdrawal but patients can no longer use the combination.

Use of the pills, which are prescription- only, is lower in the UK but tens of thousands of people are known to be taking them. Last year 9,000 prescriptions were issued for fenfluramine and 52,000 for dexfenfluramine. Experts say they are the only drugs which have been shown to achieve and maintain weight loss.

The US Food and Drug Administration asked manufacturers to withdraw the pills after reviewing the records of 291 patients, of whom 30 per cent were found to have abnormal echocardiagrams, indicating heart defects. It warned about the drugs in July after doctors at the Mayo Clinic, Minnesota, said they had discovered 24 cases of a rare heart-valve defect in women who took fen-phen. The warning elicited reports of dozens more cases, which led to yesterday's withdrawal.

The UK Department of Health yesterday alerted all doctors to the withdrawal by electronic message. It said some patients might have to stop the drug gradually to avoid suffering side-effects.

The Royal College of Physicians, which published a report on drug treatment of obesity in May, last night said it was withdrawing its recommendations.

Nick Finer, a specialist in obesity at the Luton and Dunstable Hospital, said: "One of the most promising drugs we have had against obesity appears to be under a cloud. We need drugs to treat obesity, because other treatments more often than not fail. It would be a great shame if this led to a prejudice against drugs."