You’ll hear buzz about new injectable Mounjaro (tirzepatide)...the first “twincretin” for type 2 diabetes.
Think of Mounjaro as similar to a glucagon-like peptide-1 (GLP-1) agonist...but it’s also a glucose-dependent insulinotropic polypeptide (GIP) agonist. More twincretins are in the works.
GLP-1 and GIP stimulate insulin release, increase satiety, and decrease glucose production.
Both hormones are secreted in the gut in response to food...so the dual mechanism doesn’t seem to increase risk of hypoglycemia.
Adding once-weekly Mounjaro to metformin reduces A1c by up to 2.3%...similar to Ozempic (semaglutide), the most “potent” GLP-1 agonist...when either is titrated to max doses.
Mounjaro may also lead to weight loss of up to 25 lb over 10 months in patients with diabetes...about 10 lb more than Ozempic.
Consider downsides. Data on Mounjaro’s CV outcomes aren’t expected until 2025. But some (GLP-1 agonists (Ozempic, etc) or SGLT2 inhibitors (Jardiance, etc) are shown to lower CV risk.
When a metformin add-on is needed for patients at high CV risk, lean toward a GLP-1 agonist or SGLT2 inhibitor with proven CV benefit.
But think of Mounjaro for patients at lower CV risk...especially if maximizing weight loss is a priority and payer coverage isn’t a barrier.
Be aware that Mounjaro labeling cautions about possible reduced efficacy of oral contraceptives...due to delayed gastric emptying.
This effect lessens with time. Choose a non-oral method (ring, IUD, etc) or backup for 4 weeks after starting and each titration.
You’ll also hear Mounjaro may lead to weight loss of up to 47 lb over 18 months in patients with obesity but withOUT diabetes.
But don’t use it for weight loss alone yet...it’s not approved and likely won’t be covered.
- N Engl J Med. 2021 Aug 5;385(6):503-515
- Lancet Diabetes Endocrinol. 2021 Sep;9(9):563-574
- N Engl J Med. 2022 Jun 4. doi: 10.1056/NEJMoa2206038
- Medication pricing by Elsevier, accessed Jun 2022