Semaglutide

Risks to know about

• • Boxed warning — thyroid C-cell tumors. In rodent studies, GLP-1 medicines caused thyroid C-cell tumors; whether this occurs in humans is unknown. Do not use if you or a family member have had medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Tell your provider immediately about any neck lump, hoarseness, trouble swallowing, or shortness of breath.
• • Serious risks reported with this medication class include pancreatitis (severe abdominal pain that may radiate to the back — stop and seek care) and gallbladder disease, including gallstones and cholecystitis.
• • Kidney injury, typically from dehydration after vomiting or diarrhea.
• • Hypoglycemia (low blood sugar), especially if you also take insulin or a sulfonylurea.
• • Severe gastrointestinal effects, including delayed stomach emptying (gastroparesis) and, rarely, bowel obstruction or ileus.
• • Worsening of diabetic retinopathy in some patients with diabetes, and reports of allergic reactions.
• • Anesthesia and surgery: these medicines slow stomach emptying, which can increase the risk of pulmonary aspiration under anesthesia. Tell every anesthesiologist, surgeon, and proceduralist that you use this medication — current guidance may require pausing it before sedation or surgery.
• • Pregnancy and fertility: do not use while pregnant, while breastfeeding, or while trying to conceive; stop this medication in advance of a planned pregnancy as your provider directs. Weight loss itself may increase fertility.
• • Vision changes, including rare reports of sudden vision loss (non-arteritic anterior ischemic optic neuropathy, NAION). Seek urgent medical care for any sudden decrease in vision and inform your provider.
• • Reduced absorption of oral medicines, including oral hormonal contraceptives. If you use oral birth control, discuss backup or alternative contraception with your provider.
• • Mental health: report any new or worsening depression or thoughts of self-harm to your provider immediately.
• • Dosing accuracy: compounded GLP-1s may be dispensed as multi-dose vials with syringes rather than pre-set pens, and dosing errors have been reported nationally with vial-and-syringe dosing. Use exactly the dose and volume your provider and pharmacy instruct, and ask before injecting if anything is unclear.
• • Realistic expectations: weight loss varies, and rapid weight loss can cause gallstones and loss of muscle mass. Treatment works alongside — not instead of — nutrition, activity, and sleep. No specific amount of weight loss is guaranteed.