Side Effects of GLP‑1 Medications: What to Expect and When to Call a Clinician

Common, usually temporary effects

Nausea or vomiting

Diarrhea or constipation

Abdominal pain or bloating

Decreased appetite and early fullness
Most occur during dose escalation and improve as your body adapts. Eating smaller meals, avoiding high‑fat foods, and escalating as prescribed can help.
 

Less common but important
 

Gallbladder problems: Call if you have severe right‑upper‑quadrant pain, fever, or jaundice.
 

Pancreatitis: Sudden, severe abdominal pain that won’t go away. Stop the drug and seek care.
 

Acute kidney injury from dehydration: Maintain fluids, especially if you have vomiting or diarrhea.
 

Diabetic retinopathy complications: Monitor vision if you have diabetes and rapid glucose improvement.
 

Boxed warning and who should not take them
 

All semaglutide and tirzepatide products carry a boxed warning for thyroid C‑cell tumors seen in rodents. Do not use if you or a family member has medullary thyroid carcinoma (MTC) or MEN2. Discuss thyroid nodule symptoms with your clinician.
 

Pregnancy, fertility, and surgery
 

Pregnancy: Stop once pregnancy is recognized. Discuss plans to conceive and timelines for washout.
 

Anesthesia/sedation: GLP‑1s delay gastric emptying. Tell your surgical team; they may adjust timing.
 

Drug interactions and combinations
 

Using GLP‑1s with insulin or sulfonylureas can increase hypoglycemia risk; doses may need adjustment. Do not combine tirzepatide products or mix a GLP‑1 with Zepbound (label discourages coadministration with any GLP‑1 RA).
 

What to do if side effects hit
 

Follow the titration schedule set by your prescriber.
 

Eat smaller, lower‑fat meals; pause overeating.
 

Hydrate; consider oral rehydration if vomiting/diarrhea.
 

If severe or persistent symptoms occur, contact your clinician promptly.
 

Emergency signs: severe abdominal pain (possible pancreatitis), signs of gallbladder infection, allergic reactions (swelling, difficulty breathing), or vision changes with diabetes. Seek urgent care.