Are you dying to lose weight? Would you go so far as to take diet pills?  If so, you're in good company.  Sales of diet pills, both prescription and non-prescription, topped $1 billion in the US.  So it's noteworthy that a recent analysis of the data in a study of one of the newest weight loss prescription medications, sibutramine (Meridia), questions its safety.  Based upon this data, the European Medicines Agency went as far to ban its sale in Europe last week.  Here in the US, the FDA has required only new labeling until a complete report is available in March.  The FDA has asked Abbott Laboratories, the manufacturer of Meridia, to include a warning against it use for people with a history of heart disease, strokes, or uncontrolled hypertension.  

Obesity in America

If you are struggling with your weight, you're in the majority.  Almost 70% of Americans are overweight or obese, with more than 1/3 of American adults falling into the obese category.   According to the CDC, in 2008, only one state (Colorado) had an adult obesity prevalence of less than 20%. Thirty-two states had an obesity prevalence of 25%, and six states had an obesity prevalence of 30%.  Medically, the main reason to treat obesity is because it is a major risk factor for cardiovascular disease, diabetes, and some cancers.  It is true that some obese people can be "fit" from a cardiovascular and metabolic standpoint, with normal lipids (cholesterol), blood sugar levels, and normal blood pressure.  But even in these cases, there are a host of other issues that accompany excess body weight. Obesity contributes to disability by exacerbating back pain, arthritis, acid reflux, and sleep apnea, and can increase the likelihood of having gallstones, among other conditions.  

There is no question that losing weight is a difficult process for most, which is why pills start to look tempting.  And if diet, exercise, and nutrition counseling fail, or if weight loss surgery is being considered, a trial of weight loss medication should be considered.

What is Meridia and How Does It Work? 

Sibutramine, marketed as Meridia in the US and as Reductil in Europe and other parts of the world, works by causing satiety, or the feeling of being full.  It does this by altering levels of neurotransmitters, or biochemicals in the brain.  In people who complete one year of therapy, the average weight loss is 10 percent of the initial body weight (5 percent more than those who took a placebo treatment).  It is labelled for use for up to two years maximum.  It is manufactured by Abbott Laboratories.  Abbott's global profits from Meridia totaled $300 million last year, according to the New York Times. 

What Did The Study Show?

The study, known as the Sibutramine Cardiovascular Outcomes, or SCOUT trial, was designed to evaluate the effectiveness of Meridia not just in causing weight loss, but in preventing the consequences of being obese-- cardiovascular disease.  This is the first study to look at the efficacy of weight loss drugs for an endpoint other than simply weight loss.  The European study looked at over 10,000 subjects who had cardiovascular risk factors, including known cardiovascular disease, diabetes, or hypertension, for six years.  About 11.4% of these high-risk patients who took Meridia during the study period had a cardiovascular outcome- heart attack,stroke, or death from these causes.  It was thought to do so by raising blood pressure and heart rate.  According to the New York Times, a spokesperson for Abbott states that "the high-risk patients in the study were not the intended audience for the drug" and did not take it in accordance with labeling directions, by taking it for more than the maximum duration (one year in Europe and two years in the US) recommended by the manufacturer, and by continuing to take it even if they lost no weight after six months.

Aside from sibutramine, the prescription weight loss medications currently available in the US include:

phentermine, diethylpropion- related to amphetamine.  For short term use (up to 12 weeks) only.  May be habit forming.  Increases blood pressure and heart rate.  

orlistat (Xenical or as lower dose OTC, Alli)- works by decreasing your body's ability to absorb fat.  May be used for up to 4 years.  After one year of treatment with orlistat, the average weight loss is approximately 8 to 10 percent of initial body weight (4 percent more than those who took a placebo). 

 Are Diet Pills Effective, Anyway?

As a whole, weight loss medications can achieve a modest reduction in body weight, up to 10%.  However, this is only a small increase above standard care-- nutritional counseling plus lifestyle modification, plain old diet and exercise.   More benefit occurs when diet and exercise and intense nutritional counseling are combined with a weight loss medication, compared to either alone.  However, none of these pills can be taken for more than a few years, and people typically regain wait after discontinuation of any weight loss medication.

Should Anyone Take Diet Pills?

The decision to prescribe any medication should be based upon a careful weighing of potential benefits versus risks.  While obesity is a known risk factor for cardiovascular disease and death, the results from the SCOUT trial question whether the method of achieving weight loss, in this case the use of the diet pill sibutramine, is equally important to consider.

Bottom Line 

What is clear from the research available of all weight loss medications is that there is no magic bullet.  No pill, on its own, is effective in promoting sustainable weight loss without an ongoing behavioral and lifestyle modification program of diet and exercise.  Without making permanent lifestyle changes, weight loss achieved through medication is not sustainable, and as this study points out, possibly unsafe. 

© Linda Shiue, 2010