GLP-1 medications slow stomach emptying, which can affect how your body absorbs other medications. Most common medications don't need dose changes, but some important interactions exist - especially with insulin, sulfonylureas, oral contraceptives (with tirzepatide), and time-sensitive medications like warfarin.
Insulin + sulfonylurea: Taking insulin is an absolute contraindication for GLP-1 therapy and cannot be overridden. If you currently take a sulfonylurea, your provider will review your regimen before starting.
Oral contraceptives + tirzepatide: Tirzepatide can lower the effectiveness of oral hormonal birth control during initiation and for 4 weeks after each dose increase. Use a non-oral method or add a barrier method during these windows. Semaglutide does not carry this interaction.
Time-sensitive medications: Warfarin, certain antibiotics, and some pain medications can be affected by slowed gastric emptying, particularly when starting tirzepatide. Take these as prescribed and discuss monitoring with your provider.
Most common medications including PPIs, statins, SSRIs, and blood pressure medicines don't need dose changes when starting a GLP-1. Your provider may want to monitor more closely during initiation.
Always share your full medication list with your Belle provider and any other prescribers.