What to Expect from Anesthesia at Your Colonoscopy

Lucky you! It's time for your colonoscopy! Whether you are right on schedule as a 45 year old headed into your first screening colo (that's GI-speak for colonoscopy) or you're having some GI issues requiring a quick look, rest assured that you are in good company. 15 million colonoscopies happen every year in the United States. Although colonoscopy is an incredibly common procedure, anxiety regarding what could happen the day of your procedure can make the idea of this procedure feel a little scary.

Whether this is your first one or your 5th one, I want to take you through the typical anesthesia experience for patients scheduled for colonoscopy and provide a few do's and don'ts. Hopefully, if I can help you understand what to expect, you will feel more relaxed as you head into the big day!

Why do I need a colonoscopy?

A colonoscopy is a routine procedure to examine the colon for signs of abnormalities, such as polyps or early cancer, often recommended for screening or to investigate digestive symptoms. Patients who are having GI symptoms or who have a family history of colon cancer may be at a higher risk for developing colon cancer. Regardless of your risk, you should have a screening colonoscopy at age 45.

While you’ve likely discussed the procedure with your gastroenterologist or general practitioner, the anesthesia part might feel unfamiliar since you typically meet your anesthesia provider only on the day of the procedure. Let’s demystify it together to make it feel less scary.

What Type of Anesthesia Is Used for a Colonoscopy?

The most common anesthesia method for a colonoscopy is monitored anesthesia care (MAC), also known as IV sedation or “twilight anesthesia.” In rare cases, other approaches like general anesthesia may be used, particularly for complex cases or specific medical needs. Below, I’ll explain MAC in detail, as it’s the standard approach, and touch on general anesthesia briefly, focusing on what you can expect.

Monitored Anesthesia Care (MAC): The Standard Approach

Purpose:

MAC involves IV sedation to keep you relaxed, comfortable, and drowsy during the colonoscopy. It ensures you feel no pain and often have little to no memory of the procedure, while allowing you to breathe on your own and recover quickly. This is ideal for a colonoscopy, which typically lasts 15–30 minutes and is performed in an outpatient setting.

The Process:

• Before the Procedure: On the day of your colonoscopy, you’ll arrive at the hospital or endoscopy center and check in. A nurse will take your vital signs and place an IV in your arm or hand to deliver fluids and sedation medications. You’ll meet your anesthesia provider (a nurse anesthetist like me or an anesthesiologist) in the preoperative area, where we’ll review your medical history, discuss any concerns, and confirm the anesthesia plan.

  
  

• In the Procedure Room: Next, you’ll be wheeled into the procedure room on a stretcher. The room may feel cool and busy as the team prepares equipment, but we’ll keep you comfortable with warm blankets. We’ll connect you to monitors to carefully track your heart rate, blood pressure, and oxygen levels throughout your procedure.

  
  

• During MAC: Once you’re positioned (usually lying on your left side), your anesthesia provider will administer sedation medications through your IV, such as propofol or midazolam. These medications help you relax and drift into a light sleep-like state. You’ll breathe on your own, and no breathing tube is needed.

  After you fall asleep, your procedure will begin. Your anesthesia provider will monitor your vital signs as well as your physical reactions throughout the procedure extremely closely to ensure that you are safe. Propofol wears off very quickly once it's given, so you will be given a continuous infusion until the procedure is over. Most colonoscopies last about 20-30 minutes and your anesthesia provider never leaves your side.

  
  

• After the Procedure: Once the colonoscopy is complete, the sedation is stopped, and you’ll begin to wake up quickly. You’ll be moved to the recovery area, where a nurse will monitor you until you’re fully alert and ready to go home (typically within 30 min to 1 hour).

  
  

What It Feels Like:

The IV placement may feel like a quick pinch. As the sedation begins, you will feel a pleasant sense of relaxation. During MAC, you’ll be in a twilight state—drowsy, relaxed, and unaware of the procedure. Many patients don’t remember anything at all, though some recall vague snippets, like hearing voices or feeling gentle pressure. There’s no pain, and any discomfort (like bloating from air used during the procedure) is managed in recovery. You may feel groggy initially but will feel like yourself within a short time.

Want to learn about all of the anesthesia types? Click the image below to read What Is Anesthesia? Understanding the Types and Their Safety.

What Is Anesthesia? Understanding the Types and Their Safety

General Anesthesia (For Rare Cases)

Purpose

General anesthesia, which puts you fully asleep, is rarely used for colonoscopies but may be necessary for patients with specific medical conditions or complex procedures. It ensures you’re completely unconscious and unaware during the procedure.

The Process:

• Before the Procedure: Your anesthesia provider will explain why general anesthesia is needed and review your medical history. An IV will be placed for medications and fluids.

  
  

• During the Procedure: In the procedure room, the same monitors will be used as with MAC. You will breathe oxygen through a mask and then receive IV medications to fall asleep quickly. A breathing tube or airway device will be placed after you're unconscious to help you breathe. We’ll monitor you closely throughout your procedure.

  
  

• After the Procedure: As the procedure ends, the anesthesia is stopped, and you’ll wake up in the recovery area after the airway device is removed. You may feel groggy or slightly confused at first but will recover within about an hour.

  
  

What It Feels Like:

Going under general anesthesia feels like drifting off to sleep. You won’t feel or remember the procedure. Waking up may feel like coming out of a deep nap, with possible grogginess or a sore throat from the airway device, which we’ll manage with medications or lozenges.

Still curious about general anesthesia? Click the image below to read General Anesthesia: The Patient Experience from Start to Finish.

General Anesthesia: The Patient Experience from Start to Finish

Why You Don’t Need to Worry

It’s normal to feel nervous about anesthesia. Rest assured, MAC is a safe, widely used method for colonoscopies, designed to keep you comfortable with minimal side effects. Your anesthesia team is highly trained, using advanced monitoring to ensure your safety throughout the procedure.

Colonoscopies are quick, and the sedation allows you to recover rapidly and return home the same day.

Here are a few tips to prepare mentally:

• Ask Questions: Share any concerns with your anesthesia provider, such as worries about sedation or waking up during the procedure (which is extremely rare with MAC).

  
  

• Focus on the Benefits: A colonoscopy is a powerful tool for detecting and preventing colon issues, and anesthesia ensures you’re comfortable during this quick process.

  
  

• Trust Your Team: Your anesthesia provider and gastroenterologist work together to make the procedure smooth and safe, staying with you the entire time.

Important Tips for a Successful Colonoscopy!

• NPO (Nothing By Mouth):

  Your doctor's office will inform you about when to stop eating and drinking, as well as how and when to take the colon prep medication. Please pay attention to these instructions as they will have a huge impact on the effectiveness of your test.

  
  

  Regardless, you should not have any liquids, gum, mints, tobacco dip, or chewing tobacco within 2 hours of your procedure time. Eating or drinking within certain windows of time near your planned anesthesia time is very dangerous. Patients who consume food or even clear liquids too close to the time for anesthesia risk having gastric contents come up from their stomach and enter their airway.

  
  

• Pregnancy:

  If you are pregnant or think you could be pregnant, be sure to tell your nurse or anesthesia provider before heading to the procedure room. While propofol isn't known to cause birth defects or harm, there is increased risk for aspiration if you are pregnant.

• Diabetes:

  If you are diabetic, be sure to let your GI doctor know when scheduling your test. Often, diabetic patients are scheduled for earlier in the day. Do not take your diabetes medications on the morning of your procedure unless you are a type I diabetic monitoring your blood sugar levels meticulously or are on an insulin pump.

  Diabetes medications lower your blood sugar (glucose level). If you are not eating or drinking and continue to take diabetes medications, your blood sugar level can drop quickly which can lead to a medical emergency.

• Weight Loss Medications

  Ozempic, Semaglutide, Wegovy, Zepbound and other weight loss medications can cause your stomach to stay full for longer. While this may be helpful in losing weight, that full stomach can be dangerous for a patient receiving anesthesia medication as this can increase your risk for aspiration.

  Tell your doctor and your anesthesia provider that you are taking this medication prior to arriving for your procedure. Sometimes a liquid diet must be followed or the medication withheld for a period of time prior to your procedure.

• Blood Pressure Medication

  Generally, you should take your blood pressure medication as directed unless you have been specifically asked not to do so by a physician or pre-operative nurse. If taking medication, swallow only the pill with the smallest amount of water possible- preferably one tablespoon of water.

• Driving

  Many people report feeling great after waking up from a good propofol nap. Despite this, you still aren't ready to get behind the wheel. Always have a driver bring you to your colonoscopy and take you home. In fact, this is likely a requirement of the facility where your test will be performed.

  Although the general anesthesia effects of propofol wear off quickly, you will still need to refrain from driving for the rest of the day and night. Stay home. Rest. Eat. Drink. Do not make big decisions, email your boss, or buy anything online that can't be returned.

Final Thoughts

Anesthesia for a colonoscopy, typically achieved with monitored anesthesia care (MAC), is designed to keep you relaxed, comfortable, and pain-free. With MAC, you’ll drift into a twilight state, unaware of the process, and wake up feeling refreshed. General anesthesia, while rare, is a safe alternative for specific cases.

Rest assured that thousands of these procedures are performed daily without a hitch, and yours is going to go well too! Follow your pre-operative and post-operative instructions to a tee, and then just take a deep breath and relax. Your anesthesia provider has got it from here.

By understanding what to expect, you can approach your colonoscopy with less anxiety and more confidence, knowing it’s a vital step in maintaining your health. If you have questions before your procedure, don’t hesitate to check out more articles here or reach out to your healthcare team—we’re here to support you. Prepared patients have better outcomes!

Want to learn more about anesthesia for specific procedures? Click the icon below for a list of Articles!

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**Information provided is intended as general healthcare information for the public and should be used as a guide. This information should not be substituted for the specific personal advice recommended by your own healthcare team who are familiar with your specific health history.*