Stories relating to diet pills bought over the internet are regular features in the news. While it is possible to buy safe medicine such as Xenical and Orlistat on prescription from online pharmacies, there are unfortunately many unscrupulous websites selling treatments which aren’t safe, or even legal.

The dangers of illegal diet pills is a subject we've tackled elsewhere. But there are also other treatments, which were once legal, but have since been taken off the market due to their high risk of harmful side effects.

Sibutramine, also known as Reductil, is one example.

What was Sibutramine?

Sibutramine was a widely used weight loss treatment before being withdrawn in the United Kingdom in 2010 due to safety concerns that it could potentially increase the risk of strokes or heart attacks.

Its use has also been suspended in the United States, Europe and China.

Who was Sibutramine for?

It was available on prescription to patients with a Body Mass Index (BMI) of over 30, or those with a BMI of 27 who were also at high risk of developing conditions such as type 2 diabetes or high blood pressure. The medication was designed to be taken alongside a fitness programme and a controlled diet.

How did Sibutramine work?

Launched in 1998 after first being developed in Britain, Sibutramine was an appetite suppressant, and worked by increasing the levels of serotonin and noradrenaline in the brain. These are known as inhibitory neurotransmitters, and induce feelings of fullness after eating. Sibutramine helped augment these feelings, so the appetite would be satisfied after eating less food.

Though not as widely used as Orlistat, it was used by 86,000 people in 2009.

Why was Sibutramine withdrawn?

The tablets proved to be controversial from the start; its efficiency in treating weight loss was questioned when an American survey found that patients taking 10mg of the drug for one year only lost an average of six and a half pounds.

Already not deemed suitable for use by patients with a history of strokes, heart problems or high blood pressure, safety concerns caused the European Medicines Agency (EMA) to review the medication in 1999 and 2002, which found the benefits to outweigh the risks.

In 2002, the EMA asked the manufacturer of Reductil, Abbott Laboratories, to conduct a study into the safety and efficiency of the drug in a large sample of obese patients. Following the progress of nearly 10,000 people over six years, and comparing it with a placebo, it was found that the use of Sibutramine only led to modest, short term weight loss, and was more likely to cause heart problems than the placebo.

The EMA suspended all licenses in Europe for Sibutramine in January 2010, citing the research that concluded the potential side effects, including the risk of strokes and non fatal heart attacks, outstripped the benefits of the treatment. It was withdrawn in many other countries later the same year.

Sibutramine can still be found in illegal diet pills, many of which purport to be herbal remedies, and continue to be seized by local councils and the Food Standards Agency. Unlicensed diet pills can have dangerous, even life threatening side effects, and it is strongly advised by health organisations to avoid them.

Alternatives to Sibutramine

Only one weight loss treatment is currently available by prescription. Orlistat, also marketed as Xenical, is prescribed to overweight patients for whom a regimen of diet and exercise has not been adequately effective, and is used in conjunction with a continued fitness programme.

An over the counter tablet, known as Alli, contains a lower dose of orlistat and is available from chemists, following discussion with your pharmacist.

If you are looking assistance with losing weight, you should first see your doctor, who will be able to help you find the causes of your weight gain and a set plan of action to improve your health, which may or may not include medication.

Page last reviewed:  28/09/2021