Hormonal
GLP-1 RAs can cause clinically significant drug-drug interactions (DDIs) by delaying gastric emptying, particularly affecting the absorption of oral contraceptives and levothyroxine.
If you take oral contraceptives or levothyroxine, be aware that GLP-1 drugs can change how well these work by slowing stomach emptying. Your doctor may need to monitor your levels or adjust doses. Use backup contraception if advised.
Mechanism-of-action-mediated DDIs are currently limited to those involving delayed gastric emptying... significant changes in exposure were observed for oral contraceptives and levothyroxine following the administration of tirzepatide and oral semaglutide, respectively, indicating the need for close monitoring in these instances.
Why this rating
Based on specific clinical observations noted in the review, though described as 'limited' compared to enzyme-mediated DDIs.
Source
A Comprehensive Review on the Pharmacokinetics and Drug−Drug Interactions of Approved GLP-1 Receptor Agonists and a Dual GLP-1/GIP Receptor Agonist
Jee Sun Min et al. · Drug Design Development and Therapy · 2025
DOI 10.2147/dddt.s506957
Related findings · Hormonal
- Initial treatment for type 2 diabetes should be a combination of metformin and either an SGLT-2 inhibitor or a GLP-1 receptor agonist to achieve cardiorenal protection, rather than monotherapy or older agents like sulfonylureas.Strong
- For patients with specific monogenic obesity syndromes (leptin deficiency, POMC/PCSK1/LEPR mutations), targeted pharmacotherapy (recombinant leptin or setmelanotide) is highly effective and should be prioritized, unlike in polygenic obesity.Strong
- Continued weekly administration of 2.4 mg subcutaneous semaglutide prevents weight regain and promotes further weight loss in adults with overweight or obesity, whereas switching to placebo results in significant weight regain.Strong
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