DRUGS FOR OBESITY ARE LAST REORT TREATMENT

by Hilary Bower, London

Appetite suppressant drugs should be prescribed as a last resort and only to patients who are clinically obese and respond rapidly to them, say new guidelines designed to crack down on the inappropriate use of slimming drugs.

The report, compiled by an expert working party of the Royal College of Physicians of London, concludes that treatment with anti-obesity drugs is appropriate only for people with a body mass index greater than 30 who fail to reduce their weight by 10% after three months determined effort with diet, exercise, and behavioural change.

Drugs for obesity must be combined with behavioural change

Even then, the authors say, slimming pills should be prescribed for more than three months only if patients achieve a 10% reduction in that time and do not regain more than 3 kg.

The report was commissioned by the Department of Health after widespread concern over the misuse of the drugs by private slimming clinics prompted calls for a complete ban on anorectic agents.

It backs continued prescription of centrally acting appetite suppressants but notes that only one in nine patients is likely to benefit from longer term prescription of dexfenfluramine, the only anti-obesity drug currently licensed in Britain for use beyond 12 weeks.

The authors say that there are too few data on long term safety to support the use of the drugs beyond 12 months, and they categorically dismiss the use of amphetamines, selective serotonin reuptake inhibitors, and diuretics for the treatment of obesity.

Professor David Grahame-Smith, a member of the working party and Rhodes professor of clinical pharmacology at the John Radcliffe Hospital, Oxford, said: "We have taken away a lot of the mythology about what drugs can be used for obesity, and what we are left with is dexfenfluramine."

He added: "But let's be clear, the basis of losing weight is diet and lifestyle change. Dexfenfluramine helps, but it isn't God's gift to the obese."

Professor Grahame-Smith said data showing a 30-fold increase in the rare but serious occurrence of primary pulmonary hypertension after three months of taking centrally acting appetite suppressants were worrying but must be balanced against substantial reductions in the far greater risk of cardiovascular and cerebrovascular events prompted by obesity.

He urged doctors to ensure drug use was part of a disciplined medical protocol and monthly monitoring. This approach concurs with the recent Effectiveness Bulletin on the management of obesity produced by the NHS Centre for Reviews and Dissemination in York.

Susan O'Meara, research fellow at the centre, said: "The concern is that there is pattern of weight regain after six to nine months of drug therapy. Maintenance strategies which involve diet, behaviour, and lifestyle changes in combination are most successful." But she added that the Effectiveness Bulletin had found that selective serotonin reuptake inhibitors also gave similar short term benefits.