FDA flags intestinal obstruction and fecal impaction as possible risk for GLP-1 drugs including Mounjaro and Zepbound
FDA's April-June 2025 monitoring report flags intestinal obstruction and fecal impaction across the GLP-1 class, including Mounjaro and Zepbound, and says a decision is still pending.
Federal regulators have added two gastrointestinal conditions, intestinal obstruction and fecal impaction, to the list of possible serious risks they are tracking across all GLP-1 receptor agonist medicines, a group that includes the tirzepatide brands Mounjaro and Zepbound [1].
The change appears in the FDA's quarterly publication of new safety information and potential signals from its Adverse Event Monitoring System, covering April through June 2025 [1]. The entry is written at the class level rather than for a single drug. It lists 14 products: Adlyxin (lixisenatide), Bydureon and Bydureon BCise (exenatide), Byetta (exenatide), Mounjaro (tirzepatide), Ozempic (semaglutide), Rybelsus (semaglutide), Saxenda (liraglutide), Soliqua 100/33 (insulin glargine and lixisenatide), Trulicity (dulaglutide), Victoza (liraglutide), Wegovy (semaglutide), Xultophy 100/3.6 (insulin degludec and liraglutide) and Zepbound (tirzepatide) [1].
The agency labels the finding a "potential signal of a serious risk," the category it uses for reports that have not been confirmed as caused by a drug [1]. The status line for the GLP-1 row, dated March 13, 2026, reads: "FDA is evaluating the need for regulatory action" [1].
The listing does not say how many reports prompted the entry, what doses or patient characteristics were involved, or how often the conditions occurred [1]. It does not separate tirzepatide from semaglutide, liraglutide or the other ingredients in the class [1]. It also does not say whether the current labels for Mounjaro or Zepbound already mention the two conditions [1].
Other rows in the same table show how differently these reviews can end. For Briumvi (ublituximab-xiiy) and Kesimpta (ofatumumab), FDA said labeling was updated in August 2025 after a liver-injury signal [1]. For one generic teriparatide injection, the agency "determined that no action was necessary at the time based on available information" [1]. For the GLP-1 entry, no labeling change is shown [1].
Why it matters for patients
A potential signal is a note that FDA is reviewing reported cases, not a finding that the drugs caused them, and the GLP-1 entry itself does not change what these medicines are approved for or how they are labeled [1]. Because the entry is written for the whole class, it covers people taking Mounjaro or Zepbound as well as those taking semaglutide products such as Ozempic, Wegovy and Rybelsus, and older GLP-1 drugs [1].
The listing gives no patient-facing instructions, no symptom list and no description of who might be at higher risk [1]. Anyone who wants to know how this applies to their own treatment has to get that from a clinician, because the FDA publication does not provide it [1]. The practical effect for now is that the two conditions are on the agency's radar and under review, while the medicines remain on the market [1].
What happens next
FDA says it is still evaluating whether regulatory action is needed on this signal, as of the March 13, 2026 status note [1]. The listing sets no deadline for a decision [1]. Outcomes shown elsewhere in the same table have ranged from labeling updates to a conclusion that no action was necessary [1]. FDA publishes these potential-signal listings by quarter, so the entry's status may be updated in a later edition [1].
Sources
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