A drug which treats obesity by reducing the desire to eat has been launched in the UK.
Obesity is a major killer
But NHS chiefs warned people not to expect it to become widely available straight away as the cost-effectiveness of the pill needed to be assessed.
Rimonabant is the first drug to target factors governing the body's appetite, metabolism and energy use. Trials showed it can reduce weight by a tenth.
UK experts said it could not replace healthy food and regular exercise.
In the UK, it is estimated that one in five men and a quarter of women are obese.
But at a cost of over £55 for a month's treatment, it could end up costing the NHS billions of pounds of money.
The drug still has to be assessed by NHS advisers the National Institute for Health and Clinical Excellence.
The review is not expected for another two years and NHS bosses warned the public not to expect its widespread use immediately.
Gill Morgan, chief executive of the NHS Confederation, said primary care trusts may be reluctant to prescribe the drug ahead of NICE guidance.
"PCTs receive a fixed allocation of money to deliver all the services for their local community and have to take difficult decisions on competing priorities."
And she added weight loss was "predominantly about diet and exercise".
The drug's manufacturer, Sanofi Aventis, has argued the drug represents good value for money when set against the £7bn per year cost of tacking obesity.
Other anti-obesity drugs are already available, but rimonabant is the only one to target the endocannabinoid system, which governs the body's appetite.
In a series of trials involving more than 6,000 patients in the US and Europe, a quarter lost more than 10% of their initial body weight after a year. About half lost more than 5%.
Side effects in some patients included nausea, dizziness and anxiety.
Significant improvements in measures of glucose control, cholesterol and triglyceride blood fats were also seen.
Rimonabant, sold under the brand name Acomplia, is currently licensed for the treatment of obese patients, or overweight patients with associated risk factors such as type 2 diabetes or poor cholesterol and triglyceride readings.
But there are also trial data suggesting that the drug can help people give up smoking by overcoming their cravings.
However at present it is only being marketed to tackle obesity.
Dr David Haslam, clinical director of the National Obesity Forum, said the drug offered a real opportunity to get to grips with the obesity crisis.
"Preventative measures aren't enough on their own. It brings into focus the priority that should be given to treatment as well as prevention.
"The launch of rimonabant is important news for patients who are overweight, with type 2 diabetes, or low HDL cholesterol or high triglycerides."
Would you consider taking this drug? Your comments:
I would not take the drug as i keep myself in shape by eating right and exercising. This should not be available on the NHS. If someone isn't willing to stop stuffing their face with burgers then they certainly shouldn't be given a pill costing the tax payer. The money would be better spent on food education and combating aggressive marketing by fast food companies. Jim, London
Oh dear. Another 'answer' to the supposed 'epidemic'. Contrary to the drug industry-fuelled hysteria, obesity is not a disease and those who wish to class it as such are usually those who stand to make money from doing so. Obesity is a symptom of our modern sedentary lifestyles. Offering pills to people such as this will do nothing to improve the health of the public in general who will continue to lead these lifestyles, albeit 10% lighter yet afflicted by bouts of nausea, dizziness and anxiety. James, UK
I bet there are lots of people in the UK who would be willing to pay the £55 per month out of their own pockets to try this drug right away. Yet there doesn't seem to be any publicity about this, and where they can obtain it from. Surely this is the immediate market for Acomplia, with no implications for NHS funding? Caroline, London
If its going to start costing that much money for a course of treatment then I propose a "Fat Tax" for clinically obese people to have a higher rate of income tax to help pay for it. I certainly dont want my tax paid earnings to go towards people who cant be bothered to eat properly. Matt Sims, Frome
Yes I will!! I've been overweight my whole life and have tried everything!! I am a male in my 30's, just about heart attack years, so I will try anything! J van Rensburg, Edinburgh
I have tried numerous obesity drugs over the years with no success, if i was given the opportunity to try this one i would jump at the chance especially if it also increases my chances of stopping smoking. Kill two birds with one stone. £55 might sound a lot but if you can reduce the number of obesity and smoking related admissions to hospital in one go the long term savings would greatly out weigh the initial cost of treatment. Neil Forrest, Tipton, West Midlands
This drug should not be available on the NHS. Being overweight is due to diet and lifestyle and is a personal choice are we such a nanny state we have to use the NHS to assist people to adopt a healthy lifestyle. the NHS resources should be used to tackle cancer and other serious illness not associated with overeating and drinking. Robert Smith, Portsmouth.