Weight and Lifestyle Management

An introduction to weight Loss medications

Until recently, good medical options have not been available in Canada to help patients lose weight and keep it off. Fortunately, we now have four medications approved by Health Canada for weight loss:

  1. Saxenda®

  2. Contrave®

  3. Xenical®

  4. Wegovy®

Currently Saxenda®, Contrave® and Xenical® are available in Canadian pharmacies and Wegovy® (semaglutide) is expected to be available in the spring of 2023. In the meantime, many Board Certified weight loss physicians like myself are prescribing Ozempic® (also semaglutide) in place of Wegovy®.

In Canada, all of these weight loss medications can be used in adult patients with an initial body mass index (BMI) of:

  • 30 Kg/m2 or greater, or

  • 27 Kg/m2 or greater in the presence of at least one weight-related comorbidity (ie, high blood pressure, type 2 diabetes, high cholesterol, fatty liver, sleep apnea, etc)

To find out if any of these agents are covered on your benefits plan, use each of the drug identification numbers (DIN) listed below each medication name to check with your benefits plan or pharmacy.

SAXENDA® (lirglutide)
Drug identification number (DIN): 02437899

Saxenda pen

Saxenda® is a daily self-administered injection that increases the effects of an appetite suppressing hormone called glucagon-like peptide-1 (GLP-1) that is found naturally in your body. Studies with Saxenda® have also shown that it may also improve waist circumference, blood pressure, blood glucose and cholesterol levels.

Click here for Cleveland Clinic information regarding Saxenda®

Click here for the official Canadian website for Saxenda®

CONTRAVE® (buproprion/naltrexone)
Drug identification number (DIN): 02472945

Contrave® is a tablet taken twice daily that combines low doses of naltrexone, a medication used to help treat alcohol or opioid dependency, and bupropion (Wellbutrin®), an antidepressant that’s also used for smoking cessation (Zyban®). These medicines work on two different areas of the brain and work especially well for people with strong cravings for food. It is important to gradually increase the dosage of Contrave® slowly up to the maximum recommended dose, two tablets administered twice daily. 

Click here for Cleveland Clinic information regarding Contrave®

Click here for the official Canadian website for Contrave®

XENICAL® (orlistat)
Drug identification number (DIN): 02240325

Xenical® is a weight loss medication that was approved in 1999. It is a capsule that is taken during or after each meal and prevents enzymes called lipases from breaking down fat, leading to your body not being able to absorb some calories from your diet which leads to weight loss. Some studies have also shown that Xenical® may also improve waist size, blood pressure, blood glucose and cholesterol levels. Unfortunately, the side effects of this medication do include significant diarrhea, which has limited how many people are willing to take this medication.

Click here for Cleveland Clinic information regarding Xenical®

OZEMPIC® (semaglutide)
Drug identification number (DIN): 02471477

While semaglutide has been approved as an injectable medication for weight loss by Health Canada, it is currently not available in Canadian pharmacies at the weight loss dose of 2.4 mg (as Wegovy®). Like many weight loss doctors I am prescribing Ozempic® (semaglutide 1 mg) instead.

Like Saxenda®, Ozempic® (semaglutide) is is a glucagon like peptide 1 (GLP-1) receptor agonist which is helps decrease appetite and has been found to lower blood sugars, cholesterol and blood pressure in multiple studies. It is available in two self-injecting pens, one that offers dial up dosing levels of 0.25 mg and 0.5 mg and another that offers dial up dosing of 1 mg.

Ozempic® has several advantages over Saxenda®:

  1. It only requires once weekly dosing.

  2. It is more affordable than Saxenda® for those without drug benefits.

  3. It can be raised close to the dosage of Wegovy® which so far leads to the most weight loss (about 15%) out of all the weight loss medications available in Canada today.

Click here for Cleveland Clinic information regarding Ozempic®

Click here to view a video on how to inject Ozempic®

FUTURE WEIGHT LOSS MEDICATIONS

The future of weight loss medications is bright with many new medications on the horizon. It is not hard to imagine a time when we will have multiple options to treat this chronic condition called obesity, just like we currently do for high blood pressure and diabetes. To start off with, a phase 3 trial with oral semaglutide 50 mg has been completed which showed good weight loss results. (1)

In addition to all of the GLP-1 medications currently on the market, the actions of several other gut hormones are being researched for weight loss including gastric inhibitory polypeptide (GIP), glucagon, gastrin and amylin.

Tirzepatide is a molecule that modulates the receptors for two hormones, GIP and GLP-1, which both increase satiety. It has been approved for diabetes by the FDA and Health Canada as Mounjaro. Since it led to over 20% weight loss in the SURMOUNT-1 trial, it was approved for weight loss by the FDA in the United States in November 2023 (as Zepbound) and will hopefully be approved by Health Canada in the near future. (2,3)

Cagrilintide is a molecule that mimics the effects of amylin, a hormone that increases satiety or fullness (like GLP-1). It has completed phase 2 trials. (4) In addition, in phase 2 trials where it was combined with semaglutide, it lead to significantly more weight loss. (5)

Cotadutide is a molecule that works on both the glucagon and GLP-1 receptors and is being studied for multiple medical conditions including diabetes and obesity. (6) A phase 2 study of survodutide which works on glucagon and GLP-1 receptors showed impressive results. (7) although it did show a significantly higher amount of nausea and vomiting than both semaglutide and tirzepatide (8).

Orforglipron is an oral non-peptide GLP-1 agonist that has just completed a phase 2 trial with 272 patients and shown impressive results. Since it is a non-peptide molecule, it should be significantly less expensive to produce, hopefully making it much more affordable than all of the current weight-loss drugs based on peptide molecules. (9)

Retatrutide works on three different incretins: GLP-1, glucagon, and GIP, and has had the best results to date - 24.2% average weight loss. However, it has only completed phase II trials. (10)

Danuglipron, a GLP-1 receptor agonist has completed phase 2 trials for diabetes and has been found to cause significant weight loss. (11)

Pemvidutide, a dual GLP-1 and glucagon agonist, which is currently in phase II trials for the treatment of fatty liver, has so far been shown to lead to significant weight loss in test subjects with a similar side effect profile to other GLP-1 receptor agonists that are currently available. (12)

  1. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01185-6/fulltext

  2. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038

  3. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01200-X/fulltext

  4. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00845-X/fulltext

  5. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01163-7/fulltext

  6. https://clinicaltrials.gov/ct2/results?term=cotadutide

  7. https://www.hcplive.com/view/ada-2023-survodutide-impresses-in-phase-2-dose-finding-trial

  8. https://www.evaluate.com/vantage/articles/events/conferences/ada-2023-toxicity-undermines-boehringer-and-zealands-incretin

  9. https://www.nejm.org/doi/10.1056/NEJMoa2302392

  10. https://www.nejm.org/doi/10.1056/NEJMoa2301972

  11. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2805054

  12. https://ir.altimmune.com/events/event-details/easl-international-liver-congresstm-2023