Warning signs to report to your prescriber

Get help right away

Signs of a serious allergic reaction

Stop the medicine and get medical help right away if you have swelling of your face, lips, tongue or throat, problems breathing or swallowing, severe rash or itching, fainting or feeling dizzy, or a very rapid heartbeat.^{[6, 5]} All four labels warn about serious allergic (hypersensitivity) reactions.^{[1, 2, 3, 4]}

Severe stomach pain that will not go away

This can be a sign of inflammation of the pancreas (pancreatitis). Stop the medicine and call your healthcare provider right away if you have severe pain in your stomach area that will not go away, with or without vomiting.^{[5, 6]} All four labels include a warning about acute pancreatitis.^{[1, 2, 3, 4]}

Call your healthcare provider

• Gallbladder problems: pain in your upper stomach, fever, yellowing of your skin or eyes (jaundice), or clay-colored stools.^{[5, 6]}
• Dehydration and kidney problems: nausea, vomiting and diarrhea can cause a loss of fluids, which may cause kidney problems. Tell your provider if these do not stop.^{[5, 6]}
• Severe stomach problems: tell your provider about stomach problems that are severe or will not go away.^[5]
• Low blood sugar: the labels note a higher risk if you also take insulin or a medicine that makes your body release insulin, such as a sulfonylurea. Signs include dizziness or light-headedness, blurred vision, anxiety, irritability or mood changes, sweating, slurred speech, hunger, confusion or drowsiness, shakiness, weakness, headache, a fast heartbeat or feeling jittery.^{[6, 2, 4]}
• Vision changes, if you have type 2 diabetes. The labels include a warning about diabetic retinopathy complications.^{[5, 6, 2, 4]}
• Heart racing or pounding in your chest that lasts for several minutes (Wegovy). The Wegovy label includes a warning about increased heart rate.^{[6, 3]}

The thyroid warning

All four medicines carry a boxed warning, the FDA's most prominent kind. In rodent studies these medicines caused thyroid C-cell tumors, and it is unknown whether they cause these tumors, including medullary thyroid carcinoma (MTC), in people.^{[1, 2, 3, 4]}

The Mounjaro and Wegovy labels, for example, say they must not be used by people with a personal or family history of MTC or with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).^{[2, 3]} Tell your healthcare provider if you get a lump or swelling in your neck, hoarseness, trouble swallowing or shortness of breath.^{[5, 6]}

Before surgery or sedation

Every label warns that food can get into the lungs (pulmonary aspiration) during general anesthesia or deep sedation.^{[1, 2, 3, 4]} Tell all your healthcare providers about any planned surgery or procedure.^{[5, 4]}

Which label lists which warning

From the Warnings and Precautions in each prescribing information (Highlights), revisions current in September 2026.^{[1, 2, 3, 4]} "No" means the warning is not listed in that label's Highlights; read your own Medication Guide for the full list.

Every label also warns never to share a pen between people. The Ozempic label adds: even if the needle is changed.^{[1, 2, 3, 4]}

Common questions