FDA lists intestinal obstruction and fecal impaction as a class signal covering both tirzepatide brands
FDA's April–June 2025 adverse event report lists intestinal obstruction and fecal impaction as a potential serious risk across the whole GLP-1 class, including Mounjaro and Zepbound, with no decision yet on label changes. [1]
The U.S. Food and Drug Administration has flagged intestinal obstruction and fecal impaction as a potential signal of a serious risk for the entire class of GLP-1 receptor agonist drugs, including both tirzepatide products, Mounjaro and Zepbound. [1]
The entry appears in FDA's quarterly report covering April through June 2025, drawn from the FDA Adverse Event Monitoring System (AEMS). Under "Additional Information," updated as of March 13, 2026, the agency's status for this signal reads: "FDA is evaluating the need for regulatory action." [1]
What the listing actually says
The signal is filed under the class heading "Glucagon-like peptide-1 (GLP-1) receptor agonists" rather than against a single brand. FDA names 14 products in the entry: Adlyxin (lixisenatide) injection, Bydureon (exenatide) for extended-release injectable suspension, Bydureon BCise (exenatide extended-release) injectable suspension, Byetta (exenatide) injection, Mounjaro (tirzepatide) injection, Ozempic (semaglutide) injection, Rybelsus (semaglutide) tablets, Saxenda (liraglutide) injection, Soliqua 100/33 (insulin glargine and lixisenatide) injection, Trulicity (dulaglutide) injection, Victoza (liraglutide) injection, Wegovy (semaglutide) injection, Xultophy 100/3.6 (insulin degludec and liraglutide) injection, and Zepbound (tirzepatide) injection. [1]
FDA also notes on the page that the products listed in any of these potential signals "may also include the generic version of the drug product(s), if there are generic versions approved for use by the FDA at the time of this publication." [1]
The page's own title frames these entries as "New Safety Information or Potential Signals of Serious Risks." [1] That wording matters: a listing means FDA has spotted a pattern in reported cases worth a closer look, not that the agency has concluded the drugs cause the problem. The table's status column is the only public indication of where each review stands, and for the GLP-1 entry it still says the agency is evaluating whether regulatory action is needed. [1]
The report shows what a completed review looks like by contrast. For example, for Briumvi and Kesimpta, FDA states that labeling sections including "Warnings and Precautions" and the "Medication Guide" were updated in August 2025 to include information about clinically significant liver injury. [1] For Crysvita, labeling was updated in August 2025 for hypercalcemia. [1] For a particular generic teriparatide injection product, FDA "determined that no action was necessary at the time based on available information." [1] No such outcome is listed for the GLP-1 class entry. [1]
The same quarterly report includes a separate diabetes-adjacent entry: Fournier's gangrene for the SGLT2 inhibitor class, also still under evaluation. [1]
Why it matters for patients
GLP-1 and dual-agonist medicines slow how fast the stomach empties, and gastrointestinal complaints such as nausea and constipation are among the most commonly discussed side effects among people taking them. An FDA class signal for intestinal obstruction and fecal impaction means the agency is formally examining reports at the severe end of that spectrum, where a blockage or hardened stool can require medical attention.
Practically, three things follow from this listing. First, it covers the whole class, so switching between a semaglutide product and a tirzepatide product would not move a patient outside the scope of the review as FDA has defined it. [1] Second, nothing about prescribing has changed because of the listing itself; FDA has not announced a labeling change, a boxed warning, or any restriction tied to this signal. [1] Third, the quarterly reports are an early-stage transparency tool, so the number of reports, the rate, and whether the drugs are the cause are not stated on the page. Those details are not yet known from this source. [1]
Whether the current tirzepatide or semaglutide labels already mention obstruction or impaction in their postmarketing sections is also not addressed in this FDA report. [1]
What happens next
FDA gives no deadline for finishing the review. The agency updates these tables as evaluations close, and as of the March 13, 2026 update the GLP-1 entry remained open. [1] Possible outcomes, based on how other entries in the same table were resolved, include a labeling update, a decision that no action is necessary, or continued evaluation. [1] Patients with questions about gastrointestinal symptoms while taking these medicines can raise them with their prescriber.
Sources
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