Long-Term Safety
GLP-1 receptor agonists likely need to be used long term, potentially for life, for the effects on body weight to persist. Whether there are side effects and complications that only become apparent over time is currently unknown — especially when these medications are used for weight reduction.
Studies in rodents have suggested an increased risk of medullary thyroid carcinomas. Whether a similar signal exists in humans may only become apparent in many years. In patients who have had medullary thyroid carcinoma themselves or in the family, dulaglutide, liraglutide, semaglutide, and tirzepatide, a dual GLP-1/GIP receptor agonist, are contraindicated.
With dual agonists like tirzepatide or even triple agonists like retatrutide (GLP-1/GIP/glucagon), patients can lose significantly more weight than with the monoagonist semaglutide. Gastrointestinal events were also frequent in studies of dual agonists.
Awaiting Guideline Updates
Guidelines for using these new medications are still scarce. “There are clinical guidelines for obesity therapy, but they were all written before the GLP-1 receptor agonists came on the market,” said Dr. Yanovski. “Medical societies are currently working intensively to develop new guidelines to help doctors use these medications safely and effectively in clinical practice.”
This article was translated from the Medscape German edition. A version of this article appeared on Medscape.com.