If you take a GLP-1 medicine such as semaglutide, liraglutide, dulaglutide or tirzepatide, for diabetes or for weight loss, it is important to tell your surgeon, anaesthetist or endoscopy team before any procedure. These medicines slow down how quickly food leaves the stomach, and that can matter when you are given anaesthesia or sedation. This guide explains why, and what to discuss with your doctors.
Key takeaways
- Always tell your surgeon, anaesthetist or endoscopy doctor that you take a GLP-1 medicine, and when you took your last dose.
- GLP-1 medicines slow stomach emptying, so food can stay in the stomach longer than usual even after normal fasting.
- Many people can continue their medicine, but your team may ask you to take only liquids the day before, or to pause a dose. The plan depends on you and the procedure.
- Do not stop or skip your medicine on your own. Ask your doctors, as early as possible before the procedure date.
Why GLP-1 medicines matter before a procedure
GLP-1 medicines work in several ways. They help the pancreas release more insulin when blood sugar is high after meals, reduce appetite, and slow down how quickly the stomach empties. You can read more in our guide GLP-1 agonists explained.
Slower stomach emptying helps with fullness and weight loss, but it matters before anaesthesia or deep sedation. When you are asleep, the body’s normal protective reflexes are reduced. If food or liquid is still in the stomach, there is a small risk it could come back up and be breathed into the lungs, which is called aspiration. This is why you are asked to fast before procedures.
With GLP-1 medicines, the usual fasting time may not always be enough to fully empty the stomach. During an endoscopy, leftover food can also make it harder for the doctor to see clearly, and the procedure may need to be repeated.
Who may be at higher risk?
The chance of food remaining in the stomach may be higher if:
- You recently started the medicine or your dose was recently increased.
- You currently have nausea, vomiting, bloating, fullness or constipation.
- You have other conditions that slow the stomach, such as long-standing diabetes with nerve damage.
Tell your team if any of these apply to you, as it helps them decide on the safest plan.
Do I need to stop my GLP-1 medicine before surgery or endoscopy?
Not always. Advice on this has changed as more evidence has come in, and international anaesthesia and surgical societies updated their guidance in 2024. In general:
- Many people can continue their GLP-1 medicine, especially if they have no stomach symptoms and are on a steady dose.
- A liquid-only diet for about 24 hours before the procedure may be advised to help the stomach empty.
- A planned pause may be advised for people at higher risk. Because weekly injections such as semaglutide, dulaglutide and tirzepatide stay in the body for several days, a pause usually has to be planned about a week ahead, not the day before.
- On the day, the anaesthetist may ask more questions, check your stomach with a quick ultrasound in some hospitals, or change how the anaesthesia is given.
Hospitals may follow slightly different protocols, so always follow the instructions of your own surgeon and anaesthetist. The key is to raise it early, ideally when the procedure is first booked, so there is time to plan.
If you take a GLP-1 medicine for diabetes
If your GLP-1 medicine is part of your diabetes treatment, pausing it may raise your blood sugar for a while. Very high blood sugar around surgery can slow healing and increase infection risk, so the pause should be planned together with the doctor who treats your diabetes.
- Your doctor may adjust your other diabetes medicines for the days around the procedure.
- You may be asked to check your blood sugar more often.
- If you also take insulin or sulfonylureas, fasting before the procedure can cause low sugar. Ask for specific instructions on these medicines as well.
What to tell your surgeon and anaesthetist
- The name of your GLP-1 medicine and your current dose.
- How often you take it (daily, weekly or as a tablet) and the day and time of your last dose.
- Whether you started it or increased the dose recently.
- Any nausea, vomiting, bloating, fullness or constipation.
- All your other medicines, especially diabetes medicines, blood thinners and blood pressure tablets.
On the day of the procedure, tell the team if you ate anything after the time you were asked to stop, even something small. It is always safer for them to know.
Restarting your GLP-1 medicine after the procedure
Most people can restart once they are eating and drinking normally and are not having nausea or vomiting. Your doctor will tell you when. If you missed several weekly doses, your doctor may restart you on a lower dose to reduce side effects such as nausea; do not jump straight back to a high dose on your own. For more on missed doses, see what to do if you forget a dose, and for common side effects, see our GLP-1 side effects guide.
When to see an endocrinologist
If you have a surgery or endoscopy coming up and take a GLP-1 medicine for diabetes or weight, speak to the doctor who prescribes it as soon as the procedure is booked. At Vishuddha Endocrine Clinic, Dr. Moxit Shah can review your medicines and coordinate a plan with your surgical team, including how to manage your blood sugar around the procedure.
Seek medical help promptly after a procedure if you have repeated vomiting, cannot keep fluids down, have severe abdominal pain, or have blood sugar readings that stay very high or low.
Frequently asked questions
Do I need to stop Ozempic or Mounjaro before an endoscopy?
Not always. Many people can continue, sometimes with a liquid-only diet the day before. Others may be asked to pause a dose. Tell your endoscopy doctor you are taking it when the test is booked, and follow their advice.
Is it enough to skip my weekly injection the day before surgery?
Usually not. Weekly GLP-1 medicines stay in the body for several days, so skipping one the day before has little effect. If a pause is needed, your doctor will plan it about a week ahead.
Does this apply to minor procedures with local anaesthesia?
The main concern is with general anaesthesia and deep sedation. For minor procedures under local anaesthesia where you stay awake, it usually matters less, but still mention the medicine to your doctor.
Does this apply to GLP-1 tablets too?
Yes. Oral semaglutide also slows stomach emptying, so tell your team about it in the same way.
Will my blood sugar go up if I pause my GLP-1 medicine?
If you take it for diabetes, it may rise for a while. Your doctor can adjust your other medicines and ask you to check your sugar more often so that it stays in a safe range around the procedure.
Need personalised advice? Book a consultation with Dr. Moxit Shah at Vishuddha Endocrine Clinic, Ahmedabad. Book an appointment or call +91 99799 92797.
This article is for general education and does not replace a consultation. Please speak to your doctor before making any change to your treatment.
