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Long term pharmacotherapy for obesity and overweight: updated meta-analysis

BMJ 2007; 335 doi: (Published 06 December 2007) Cite this as: BMJ 2007;335:1194

This article has a correction. Please see:

  1. Diana Rucker, clinical fellow1,
  2. Raj Padwal, assistant professor1,
  3. Stephanie K Li, assistant clinical professor1,
  4. Cintia Curioni, assistant professor2,
  5. David C W Lau, professor3
  1. 1Department of Medicine, University of Alberta, Edmonton, AB, Canada
  2. 2Department of Nutrition, Faculdade Arthur Sá Earp Neto, Petrópolis, Rio de Janeiro, Brazil
  3. 3Department of Medicine, University of Calgary, Calgary, AB, Canada
  1. Correspondence to: R Padwal rpadwal{at}
  • Accepted 26 September 2007


Objective To summarise the long term efficacy of anti-obesity drugs in reducing weight and improving health status.

Design Updated meta-analysis of randomised trials.

Data sources Medline, Embase, the Cochrane controlled trials register, the Current Science meta-register of controlled trials, and reference lists of identified articles. All data sources were searched from December 2002 (end date of last search) to December 2006.

Studies reviewed Double blind randomised placebo controlled trials of approved anti-obesity dugs used in adults (age over 18) for one year or longer.

Results 30 trials of one to four years’ duration met the inclusion criteria: 16 orlistat (n=10 631 participants), 10 sibutramine (n=2623), and four rimonabant (n=6365). Of these, 14 trials were new and 16 had previously been identified. Attrition rates averaged 30-40%. Compared with placebo, orlistat reduced weight by 2.9 kg (95% confidence interval 2.5 kg to 3.2 kg), sibutramine by 4.2 kg (3.6 kg to 4.7 kg), and rimonabant by 4.7 kg (4.1 kg to 5.3 kg). Patients receiving active drug treatment were significantly more likely to achieve 5% and 10% weight loss thresholds. Orlistat reduced the incidence of diabetes and improved concentrations of total cholesterol and low density lipoprotein cholesterol, blood pressure, and glycaemic control in patients with diabetes but increased rates of gastrointestinal side effects and slightly lowered concentrations of high density lipoprotein. Sibutramine lowered concentrations of high density lipoprotein cholesterol and triglycerides but raised blood pressure and pulse rate. Rimonabant improved concentrations of high density lipoprotein cholesterol and triglycerides, blood pressure, and glycaemic control in patients with diabetes but increased the risk of mood disorders.

Conclusions Orlistat, sibutramine, and rimonabant modestly reduce weight, have differing effects on cardiovascular risk profiles, and have specific adverse effects.


  • This paper is based on a recently updated Cochrane review that is currently undergoing peer review. The conclusions of this review represent the opinions of review authors, and are not necessarily shared by the Cochrane Collaboration.

  • Contributors: RP was responsible for conception and design, data extraction, and data analysis, cowrote the initial and final drafts, and is guarantor. DR performed data extraction and analysis and co-wrote the initial and final drafts. SKL, CC, and DCWL performed data extraction or data interpretation and cowrote the final draft.

  • Funding: None.

  • Competing interests: DCWL has received consulting and speaker fees, research grants, and travel assistance from makers of anti-obesity drugs.

  • Ethical approval: Not required.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Accepted 26 September 2007
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