Update on Weight Loss Drug Sibutramine (MERIDIA)

Worst Pills, Best Pills readers may remember that we petitioned the FDA to ban the widely prescribed weight reduction drug sibutramine (MERIDIA) in the spring of 2002 (See Worst Pills, Best Pills News, May, 2002) because a large number of people had suffered severe cardiovascular adverse effects, including many deaths, from this drug that shares some properties with amphetamines. As more people used the drug, not very effective at significant weight losses, more life-threatening adverse effects and deaths occurred — the drug causes high blood pressure and cardiac arrhythmias, along with increased heart rate. Last fall, we amended our petition to include new cases. By that time there was a total of 124 serious cardiovascular adverse events requiring hospitalization in addition to the 49 cardiovascular adverse events that resulted in death. Of the nine people 40 years old or younger who died, eight were women. Most of the other deaths were also in women.

Now, almost seven years after its ill-conceived approval by the FDA over the objection of the FDA physician who was the principle reviewer for the drug, comes a thorough review of published and some unpublished studies of people using sibutramine. The study appeared in the medical journal Archives of Internal Medicine in May of this year. In addition to their important finding that the more favorable studies were more likely to be published than the less favorable ones, here are some of the results of their review:

• Among the very obese people getting the drug, the average weight loss at 3-months was only 6.1 pounds and, at one year, only 9.8 pounds.
• Between 3 and 8 patients would have to be treated with sibutramine for one year for just one patient to achieve a 10% weight loss.
• Up to 55% of weight loss may be regained at 18 months after the discontinuation of sibutramine therapy.
• Although some experts advise the use of sibutramine as a short-term aid to long-term lifestyle modifications that promote weight loss and weight maintenance, the authors of this study “did not identify any evidence to support this theoretical use.”
• There was no direct evidence that sibutramine reduces obesity-associated morbidity or mortality.
• There is insufficient evidence to accurately determine the risk-benefit profile for sibutramine.

Ironically, there is nothing new under the sun with regard to weight reduction drugs, as with most other topics. The dangerously low FDA approval standard has led, over the years, to needless deaths and injuries from sibutramine and other diet drugs. Thirty-six years ago, in June 1968, FDA Medical Officer Dr. Robert O. Knox refused to approve the New Drug Application (NDA) for a new diet drug. This disapproval touched off a dispute between the FDA and the drug’s manufacturer, A.H. Robbins, which eventually led to the drug’s approval and Dr. Knox’s transfer to another area within the agency. His reason for recommending against approval was this: obesity is a chronic disease and there is no evidence that these drugs affect the course of the disease over the long term.

The drug Dr. Knox refused to approve was fenfluramine (PONDIMIN), a drug that ultimately became the “fen” portion of the notorious “fen/phen” combination that was removed from the market on September 15, 1997, because it caused heart valve damage and a potentially fatal adverse reaction of the lungs known as primary pulmonary hypertension.

What You Can Do

As we advised when we first wrote about sibutramine: The best advice we can give about obesity is that prevention may be the best course. Our advice about losing weight and diet pills has remained the same for 25 years: eat a little less each day, exercise a little more. This approach to losing weight is slow but effective. The only one who profits from it is you. That’s why it isn’t sold.