Pharmacotherapy in Obesity Management

Version 2. Update October 2022.

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  • Pharmacological treatments are an effective and scalable approach to treating obesity. As with any chronic disease, such as type 2 diabetes (T2DM) or hypertension, pharmacotherapy is an important pillar in the management of obesity.
  • The focus of obesity management should be the improvement of health parameters (metabolic, mechanical, mental, and/or quality of life [QoL]), not solely weight reduction, and should include outcomes that the patient identifies as important. Obesity is defined by body mass index (BMI) in clinical trials, which itself does not adequately reflect the burden of adiposity-related disease.
  • There are four medications indicated for long-term obesity management in Canada as adjuncts to health-behaviour changes: liraglutide (Saxenda®), naltrexone/bupropion (Contrave®) in a combination tablet, orlistat (Xenical®) and semaglutide (Wegovy®). All four medications are effective in producing clinically significant weight loss and health benefits greater than placebo over a duration of at least one year.
  • The individual response to pharmacotherapy for obesity management is heterogeneous. Efficacy (both for weight and management of obesity-related health issues), mechanism of action, safety, potential side effects/tolerability, contraindications, medication interactions, mode of administration and cost are important considerations in choosing the most appropriate obesity pharmacotherapy.
  • Obesity medications are intended as part of a long-term treatment strategy. Clinical trials of pharmacotherapy for obesity management consistently demonstrate regain of weight when treatment is stopped.
  • Medications that are not approved as pharmacotherapy for obesity management should not be used for this purpose.

  1. Pharmacotherapy for obesity management can be used for individuals with BMI ≥ 30 kg/m2 or BMI ≥ 27 kg/m2 with adiposity-related complications, in conjunction with medi­cal nutrition therapy, physical activity and/or psychological interventions (semaglutide 2.4 mg weekly [Level 1a Grade A],1 liraglutide 3.0 mg daily [Level 2a, grade B],2-4 naltrexone/ bupropion 16 mg/180 mg BID [Level 2a, Grade B],5 orlistat 120 mg TID [Level 2a, Grade B]).6
  2. Pharmacotherapy may be used to maintain weight loss and to prevent weight regain (liraglutide 3.0 mg daily [Level 2a, Grade B],4 orlistat 120 mg TID [Level 2a, Grade B]).7
  3. Pharmacotherapy for obesity management in conjunction with health-behaviour changes for people living with predi­abetes and overweight or obesity (BMI ≥ 27 kg/m2) can be used to delay or prevent type 2 diabetes (T2DM) (liraglutide 3.0 mg daily [Level 2a, Grade B],3 orlistat 120 mg TID [Level 2a, Grade B]).8
  4. Obesity pharmacotherapy can be used in conjunction with health-behaviour changes in people living with T2DM and a BMI ≥ 27 kg/m2, for weight loss and improvement in gly­cemic control (semaglutide 2.4 mg weekly [Level 1a, Grade A],9 liraglutide 3.0 mg daily [Level 1b, Grade A],10 naltrex­one/bupropion 16 mg/180 mg BID [Level 2a, Grade B],11 or­listat 120 mg TID [Level 2a, Grade B]).12
  5. Pharmacotherapy can be considered in conjunction with health-behaviour changes in treating people with obstruc­tive sleep apnea and BMI ≥ 30 kg/m2, for weight loss and associated improvement in apnea-hypopnea index (liraglu­tide 3.0 mg daily [Level 2a, Grade B]).13
  6. Pharmacotherapy can be considered in conjunction with health-behaviour changes in treating people living with non-alcoholic steatohepatitis (NASH) and overweight or obesity, for weight loss and improvement of NASH param­eters (liraglutide 1.8 mg daily [Level 3; Grade C],14 semaglu­tide [Level 4 Grade D]).15
  7. Metformin and psychological treatment (such as cognitive behavioural therapy) should be considered for prevention of weight gain in people with severe mental illness who are treated with anti-psychotic medications associated with weight gain [Level 1a, Grade A].16*

* Please see Taylor VH, Sockalingam S, Hawa R, Hahn M. Canadian Adult Obesity Clinical Practice Guidelines: The Role of Mental Health in Obesity Management. Available from: https://obesitycanada.ca/guidelines/mentalhealth.

  1. For people living with overweight or obesity who require pharmacotherapy for other health conditions, we suggest choosing medications that are not associated with weight gain [Level 4, Grade D, Consensus].
  2. We do not suggest the use of prescription or over-the-counter medications other than those approved in Canada for obesity management [Level 4, Grade D, Consensus].

  • Obesity medications are effective for managing weight and weight-related health issues, often in combination with healthy behaviour changes and/or psychological interventions.
  • The goals in obesity management should include improve­ment in health and should include outcomes that are important to you.
  • There are four medications approved by Health Canada for long-term obesity management in Canada: liraglutide 3.0 mg (Saxenda®), naltrexone/bupropion in a combina­tion tablet (Contrave®), orlistat (Xenical®) and semaglutide 2.4 mg (Wegovy®). These medications can help you to achieve and maintain improvements in weight and health complications associated with excess weight. These medications have been proven to be safe and effective for obesity management.
  • Medications that are not approved for obesity treatment may not be safe or effective for obesity management and should be avoided.

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