GLP-1 Agonists - FAQ

GLP-1 Agonists - Frequently Asked Questions

What are these medications?

• GLP-1 agonist is a class of medications that are used in type 2 diabetes and obesity.

• Via the incretin pathway, they stimulate insulin release, suppress glucagon release, slow down gastric emptying, and enhance central satiety signal.

• They, therefore, have favourable effect on glucose metabolism and lead to significant caloric intake reduction and resultant weight reduction, usually in the vicinity of 3 - 8 kg depending on the dose and agent used.

• GLP-1 agonists are one of a few classes of diabetes medications proven to have cardiovascular, renal and mortality benefit in large-scale prospective randomised controlled trials.

• They include Dulaglutide (Trulicity) and Liraglutide (Victoza / Saxenda).

Who are these for?

• Diabetes - GLP-1 agonists should be primarily considered in patients with type 2 diabetes with suboptimal glycaemic control despite maximal tolerated dose of metformin (+/- other agents) especially where weight loss is desired and/or significant stroke risk is present.

• Weight loss - GLP-1 agonists could also be considered for weight loss even in the absence of type 2 diabetes. Suggested cut-off is BMI >30, or >27 with weight related co-morbidity.

How to start?

• Injection technique is relatively straightforward, similar to insulin; hence, GLP-1 agonists could be started in primary or secondary care.

• Diabetes (Type 2)

  • Available in NZ = Dulaglutide (Trulicity, weekly injection) or Liraglutide (Victoza, daily injection).

  • Identical Pharmacy eligibility criteria to SGLT-2 inhibitor Empagliflozin, but funding is “either… or…”

  • Some patient could benefit from both SGLT-2 inhibitor and GLP-1 agonists. If they are willing to self-fund, self-funding SGLT-2 inhibitor ($80-100/month) is cheaper than self-funding GLP-1 agonists ($150-250/month)

  • DPP-4 inhibitor (e.g. Vildagliptin / Galvus / Galvumet) would have to be ceased when GLP-1 agonist is initiated.

• Weight loss

  • Available in NZ = Liraglutide high dose (Saxenda, daily injection)

  • Self-funding needed ($500-600/month)

  • Not available in NZ = Semaglutide (Ozempic, Wegovy) or Tirzepatide (Mounjaro), as of May 2023

• Side effects, particularly upper gastrointestinal, are common with GLP-1 agonist initiation. Slow up-titration is usually advisable for Liraglutide (Saxenda).

Should patients see an endocrinologist?

• GLP-1 agonist initiation could be done in primary care, as long as primary care doctor and team are comfortable.

• Those who have complex or difficult-to-control diabetes, or those intending to use GLP-1 agonist for weight loss are encouraged to see an endocrinologist.

David Kim, endocrinologist