GLP-1 severe gastrointestinal adverse reactions: what the labels say

All eight US labels covered here carry a section 5 warning titled Severe Gastrointestinal Adverse Reactions (October 2025 label update). It says use of these drugs is associated with gastrointestinal adverse reactions, sometimes severe. Trial rates of severe GI reactions range from under 1% on lower Ozempic doses to about 4–5% on some Wegovy, Saxenda and Trulicity arms, versus lower placebo rates. Overall GI adverse reactions are much more common than the severe subset.

Every US label says the product is not recommended in patients with severe gastroparesis. Canadian monographs for Ozempic, Rybelsus, Wegovy, Mounjaro, Zepbound and Trulicity say the same or that experience is limited / the drug was not studied in severe gastroparesis and is not recommended. Saxenda and Victoza say inflammatory bowel disease and diabetic gastroparesis have not been studied and should not be used in that population. Ask your prescriber; Glidedose does not suggest doses or who should start.

Ileus is slowed or stopped movement of the intestines. Several US labels list ileus, intestinal obstruction or severe constipation among postmarketing gastrointestinal reports for GLP-1 receptor agonists. Canadian monographs for Ozempic, Wegovy, Rybelsus, Mounjaro and Zepbound also list ileus or intestinal obstruction under post-market GI reactions; Ozempic, Rybelsus and Wegovy warn that GLP-1 RAs may be associated with severe GI disease including ileus. Contact your healthcare professional for severe or persistent GI symptoms.

From the US labels: Ozempic severe GI 0.4% (0.5 mg) and 0.8% (1 mg) vs 0% placebo; Wegovy adults injection 4.1% vs 0.9% placebo (tablet 2% vs 0%); Rybelsus 0.6% (7 mg) and 2% (14 mg) vs 0.3% placebo; Mounjaro 1.3% / 0.4% / 1.2% on 5 / 10 / 15 mg vs 0.9% placebo; Zepbound Studies 1+2 1.7% / 2.5% / 3.1% on 5 / 10 / 15 mg vs 1% placebo; Saxenda 4.8% vs 1.4%; Victoza 4.4% (1.2 mg) and 4.2% (1.8 mg) vs 1.1%; Trulicity 2.2% (0.75 mg) and 4.3% (1.5 mg) vs 1.4%. These are trial arms reported on the labels, not a dosing suggestion.

Discontinuation for GI adverse reactions was higher than placebo on every label that reports it. Examples from US labels: Ozempic 3.1% / 3.8% vs 0.4% placebo; Wegovy adults 4.3% vs 0.7%; Rybelsus 8% / 4% on 14 / 7 mg vs 1%; Mounjaro 3.0% / 5.4% / 6.6% vs 0.4%; Zepbound 1.9% / 3.3% / 4.3% vs 0.5%; Saxenda 6.2% vs 0.8% (pediatric disc. GI 8% vs 0%); Victoza withdrawals GI 4.3% vs 0.5%. Canadian section 8 figures are in the Canada table on this page (for example Rybelsus CA 4.5% / 7.9% vs 0.6% placebo; Trulicity CA 1.3% / 3.5% vs 0.2%). Logging how long nausea, vomiting, diarrhea or constipation lasted helps your prescriber decide what to do next.

The US labels elevated Severe Gastrointestinal Adverse Reactions to its own section 5 warning in the October 2025 update and state not recommended in severe gastroparesis. Canadian monographs put similar points under Gastrointestinal warnings: Ozempic and Rybelsus note GLP-1 RAs may be associated with severe GI disease including ileus and that people with gastroparesis may have more serious GI effects; Mounjaro, Zepbound and Trulicity say not studied / not recommended in severe GI disease including severe gastroparesis; Wegovy notes limited experience and post-market ileus; Saxenda and Victoza say IBD and diabetic gastroparesis were not studied and should not be used in that population. Zepbound’s Canadian monograph also reports severe GI adverse reactions in 2.7% of tirzepatide patients vs 1.2% placebo in weight-reduction trials.

Section 8 (Adverse Reactions) of each Canadian product monograph reports GI discontinuation rates from the trials. Examples: Ozempic 0.5 mg 3.9% and 1 mg 5.9% vs comparator 0.9%; Wegovy adults 4.3% vs 0.7% placebo; Rybelsus 7 mg 4.5% and 14 mg 7.9% vs 0.6% placebo; Mounjaro 3.0% / 5.4% / 6.6% vs 0.4%; Zepbound 1.9% / 3.3% / 4.3% vs 0.5% (GI led to discontinuation in 3.8% overall in the overview); Saxenda GI withdrawals 6.2% vs 0.8%; Victoza GI withdrawals 5.0% vs 0.5% comparator; Trulicity 0.75 mg 1.3% and 1.5 mg 3.5% vs 0.2% placebo. These are monograph figures, not a suggestion to stop on your own.

Ozempic, Rybelsus and Wegovy warn that GLP-1 receptor agonists may be associated with severe gastrointestinal disease including ileus / intestinal obstruction, and list intestinal obstruction (grouped with ileus) under post-market adverse reactions. Mounjaro and Zepbound list ileus under post-market gastrointestinal disorders. Trulicity reports events related to impaired gastric emptying, including severe gastroparesis. Saxenda and Victoza focus on IBD and diabetic gastroparesis not having been studied rather than an ileus post-market line in the monographs we checked.

US labels describe dose escalation schedules that exist in part to reduce gastrointestinal adverse reactions. Canadian monographs likewise note that most nausea, vomiting and diarrhea reports occur during dose escalation. That is a label design note, not a suggestion to change your dose. Never change a schedule based on this page; talk to your prescriber.

Labels tell patients to contact a healthcare professional for severe or persistent gastrointestinal symptoms. That includes ongoing nausea, vomiting, diarrhea, constipation, or stomach pain that will not go away. Severe vomiting or diarrhea also ties into the acute kidney injury / dehydration warning on the same labels. Canadian patient leaflets for several products also describe ileus as a condition where the intestine cannot push food and waste through (severe constipation with bloating, pain or vomiting).

Date and time of nausea, vomiting, diarrhea, constipation or stomach pain; how strong it was; how many days it lasted; whether you could keep fluids down; and anything your care team asked you to watch. Never log a dose change suggested by an app — Glidedose is a GLP-1 tracker for dates and symptoms so you can show your prescriber.

Ozempic 5.7; Wegovy 5.6; Rybelsus / Ozempic tablets 5.6; Mounjaro 5.6; Zepbound 5.2; Saxenda 5.7; Victoza 5.6; Trulicity 5.6. Section numbers can change when labels are revised.

The same delayed gastric emptying that drives severe-GI and gastroparesis warnings also drives the pulmonary aspiration under anesthesia warning on every US label. If you have a planned procedure, see the aspiration guide and tell your surgical team you take a GLP-1. Glidedose does not suggest holds or doses.