PAD Refills

How does the evidence for tirzepatide subcutaneous (Mounjaro^®) compare with semaglutide subcutaneous (Ozempic^®) for type 2 diabetes?

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Conclusion: In type 2 diabetes trials, tirzepatide has a larger effect on HbA1c lowering and body weight loss compared to semaglutide. It shares a similar adverse event profile and is more costly. Tirzepatide cardiovascular trials are due later this year and in 2027.

The BC Provincial Academic Detailing (PAD) service’s topic Medications for weight loss looks at the evidence for tirzepatide, semaglutide, liraglutide, naltrexone-bupropion and orlistat.¹ Visit www.bcpad.ca to book a session with an academic detailing pharmacist in your area. We received this question during PAD sessions: How does tirzepatide compare with semaglutide for type 2 diabetes?

1. Tirzepatide basics:^1-3 Tirzepatide (Mounjaro^®) is officially indicated in Canada for adults with type 2 diabetes to improve glycemic control. In the US, tirzepatide is also indicated for chronic weight management (Zepbound^®). Tirzepatide is a glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) agonist. It reduces blood sugar by increasing sensitivity to insulin, it slows gastric emptying, it reduces blood pressure and affects other hormones (such as glucagon). Tirzepatide is given as a once weekly subcutaneous injection with an initial dose of 2.5 mg which can be increased every 4 weeks to a maximum of 15 mg.
2. Effect on HbA1c and body weight in type 2 diabetes:^4,5 Type 2 diabetes trials generally enrol people with a baseline HbA1c of ~8% and body weight ~90 kg.  A 2024 systematic review found that tirzepatide lowered HbA1c and body weight more than semaglutide. Tirzepatide decreased HbA1c by 2.1% and decreased body weight by 8.5 kg. Semaglutide decreased HbA1c by 1.4% and decreased body weight by 3 kg. Both medications increase the risk of gastrointestinal adverse events and drug discontinuations due to adverse events. They share similar precautions and contraindications.
3. Cost:⁶ The annual drug cost of semaglutide subcutaneous 1 mg is ~$3030 and limited coverage is available through BC PharmaCare up to the 1 mg dose. The cost of tirzepatide ranges from $5,300 (2.5 or 5 mg dose), $7,400 (7.5 or 10 mg dose) or $10,600 (12.5 or 15 mg dose). Tirzepatide is a non-benefit under BC PharmaCare.
4. Cardiovascular trials: To date, one chronic kidney disease (CKD) and four cardiovascular (CVD) trials have been published for semaglutide which demonstrate that semaglutide improves patient-important outcomes in people at high CVD and CKD risk (refer to the table below). Tirzepatide CVD trials are ongoing and due in 2025 and 2027.

¹BC PAD Service Medications for Weight Loss (Nov 2024 updated); ²Health Canada Drug Product Database Mounjaro; ³US FDA Approved Drugs Zepbound; ⁴DRAKE Ann Intern Med 2024 (PMID:38639549); ⁵YAO BMJ 2024 (PMID:38286487); ⁶McKesson PharmaClik (accessed Apr 3, 2025 – drug cost excludes markup and professional fees)