Doctors come clean about the ‘effectiveness’ of weight loss drugs

Share This Post

My blog of 6th December last year lamented the fact that much medical research focuses not on health itself, but supposed ‘markers’ for health such as blood pressure and cholesterol levels. The main point I was aiming to make here was that in assessing a medical treatment or drug, we all (doctors included) need to keep focused on its effects on health outcomes like risk of heart disease, cancer, diabetes and, most importantly of all, death.

I was therefore interested to read a commentary in this week’s edition of the Lancet medical journal which reviewed the benefits of drugs used to help promote weight loss. The review was written by Drs Raj Padwal and Sumit Majumbar from the University of Alberta Hospital in Edmonton, Canada. In it, the authors review the effects of 3 weight loss drugs, two of which, orlistat (Xenical) and sibutramine (Reductil) are generally available. Orlistat works by reducing the amount of fat absorbed from the gut, while sibutramine acts on the brain to suppress appetite. On average, orlistat and sibutramine bring about weight losses of 3 kg and 4-5kg respectively.

In their review, Drs Padwal and Majumbar went on to balance the apparent benefits of these drugs with their potential downsides. For instance, orlistat is associated with a range of side-effects which include flatulence, faecal urgency and oily leakage from the rectum (niiice). Sibutramine is known to have the potential to cause symptoms such as constipation, palpitations, raised blood pressure and sexual dysfunction.

Crucially, though, the authors of this review went on to ask serious questions about the effectiveness of these drugs in promoting not just weight loss, but health. They make the point that the assessment of weight loss drugs should include measures of their impact on obesity related conditions (e.g. diabetes and heart disease) and death related to these conditions. At present, we simply don’t have any published data on the effects of currently available agents on these critical ‘end-points’. Only when we do, they say, can patients and their doctors be confident that the putative benefits of these drugs outweigh their risks and costs.

When it comes to the area of medical research I often find myself being sharply critical of doctors, scientists and researchers. I do feel compelled to write about incidents where it seems we are being misled and misinformed.

However, there is no doubt that from time to time individuals in the scientific community will confirm my faith in human nature by giving what would seem to be a balanced, impartial appraisal of a particular approach or treatment. To my mind, Drs Padwal and Majumbar deserve a big pat on the back for producing a review which is seems to be light-years away from the usual pharmaceutical PR puff pieces that are all too often to be found in medical journals.


1. Padwal RS and Majumbar SR. Drug treatments for obesity: orlistat, sibutramine, and rimonabant. The Lancet. 2007;369:71-77

More To Explore

Walking versus running

I recently read an interesting editorial in the Journal of American College of Cardiology about the relative benefits of walking and running [1]. The editorial

We uses cookies to improve your experience.