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Good drug, bad drug?


The Lancet has published two articles on the efficacy and safety of the anti-obesity drug Acomplia.  This has been widely reported in the news as showing that patients using the drug have well over double the risk of depression and anxiety.  This comes on top of US studies linking Acomplia to suicidal thoughts.


Acomplia offers help to obesity sufferers, but at a price of increased risk of depression and anxiety.  The risk is small but significant, yet the health and psychological benefits are substantial.  Obesity also increases anxiety and depression, so users have the challenge of things getting worse before they get better.  Weighing the benefits against the risks, there seems insufficient case for prohibition but a good argument for use with caution.

The UK Government recently labelled obesity a crisis on the scale of climate change.  Non-pharmaceutical approaches have shown little success, so the hunt is on for a drug to tackle the problem.  The most promising candidate to date is rimonabant, the active ingredient of Acomplia.  And it seems to work. A “meta-analysis” study by Christensen in the latest issue of the Lancet, reported weight loss of 4-6kg over 6-12 months and patients “much more likely to achieve a 10% weight reduction after 1 year.  These figures are significant – the same paper notes that weight loss of 5–10% is associated with improvements in cardiovascular risk profiles and reduced incidence of type 2 diabetes.  Moreover, they report startling statistics linking obesity and depression with obese women being 23% more likely to have made a suicide attempt than non-obese women, and up to 48% of individuals seeking treatment being prone to depression.

So far, so good for Acomplia, but there bad that comes with it, and that’s what has made the news.  The findings indicate an increase of depressed mood and anxiety which is quantified as 2.5 times more likely to discontinue treatment due to depression and 3 times more likely to discontinue treatment due to anxiety.  But when you look at the figures these are increases of 14 in a thousand to 30 in a thousand and 4 in a thousand to 10 in a thousand, respectively.  This is significant but minor.  Christiansen et al’s conclusion was a modest recommendation to increase alertness to these potentially severe psychiatric adverse reactions.  Hardly the ringing condemnation of the drug presented in the news reports.

As a footnote, the reported adverse side-effects of rimonabant may not be as surprising as they may at first seem.  Rimonabant was discovered when examining the effects of cannabis-related chemicals and indeed works by suppressing “the munchies” familiar to cannabis users.  Unfortunately, this same blockage is also known to increase anxiety.


Efficacy and safety of the weight-loss drug rimonabant: a meta-analysis of randomised trials, Christensen, R. et al. The Lancet (2007) Volume 370 Issue 9600 17 November 2007-23 November 2007, Pages 1706-1713

Depression and anxiety with rimonabant, Mitchell, P.B. and Morris, M.J. The Lancet, Volume 370, Issue 9600, 17 November 2007-23 November 2007, Pages 1671-1672

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