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4.5.1 Anti-obesity drugs acting on the gastro-intestinal tract

1st choiceNon-pharmacological treatment-diet and lifestyle changes
2nd choice

Orlistat capsules 120mg

Prescribing Notes

  • Refer to NICE CG189 Obesity: identification, assessment and management of overweight and obesity in children, young people and adults
  • Pharmacological treatment should be considered only after dietary, exercise and behavioural approaches have been started and evaluated
  • Drug treatment may be considered in patients as part of an overall treatment plan for managing obesity, who have a BMI ≥30kg/m2 or BMI ≥28kg/m2 plus associated risk factors
  • Patients should be informed that drug therapy will be discontinued after 3 months if they fail to lose 5% of their initial body weight since starting drug treatment (less strict goals may be appropriate for people with type 2 diabetes). Further courses should only be considered after a suitable period and patients should again demonstrate the ability to lose weight on a suitable diet
  • Continue for longer than 12 months (usually for weight maintenance) only after discussing potential benefits and limitations with the patient
  • Common side-effects with orlistat may be limited by dietary compliance (i.e. decreased fat intake)
  • Orlistat is available to buy over the counter (OTC) from pharmacies, under the brand name alli®. It is licensed for those with a BMI >28kg/m2, and is available as 60mg capsules


  • Orlistat (60mg and 120mg) has been linked to cases of oxalate nephropathy and pancreatitis. Interactions with levothyroxine and epileptic drugs have also been reported (MHRA, Drug Safety Update February 2010)