How to prepare for a flexible endoscopy is the question that arises as soon as you receive the order, and almost always with the fear of doing something wrong and having to reschedule the appointment. The short answer: tell your doctor about your medical conditions and medications, follow the fasting instructions you are given (usually 6 to 8 hours for solids), only discontinue what the specialist authorizes, and bring someone with you. With that taken care of, the exam usually goes smoothly the first time.

A common scenario: a patient arrives at seven in the morning, having fasted, but took their anticoagulant "because it was just a small pill" and didn't mention it. The exam is postponed, she loses the day, and her companion does too. Almost everything that follows is designed to prevent exactly that.

What the patient should do in the days leading up to the exam

In the days leading up to the exam, it is advisable to confirm the appointment and the type of exam, review your medications with the doctor, adjust your meals on the last day, and arrange who will accompany you. Preparation does not start the night before: it starts when you receive the order, because some decisions require consulting in advance.

If you are still unsure what the exam involves, you can read about what happens during a flexible endoscopy to arrive with realistic expectations. Here we focus on what you need to do. This is a reference schedule; your center or doctor may modify it depending on the type of endoscopy and the planned sedation.

Timing	What to do
7 to 10 days before	Confirm the date, time, and location. Ask if there will be sedation. Bring your doctor a list of everything you take, including supplements and natural products.
5 to 7 days before	If you take anticoagulants, antiplatelet medications, or have diabetes, discuss with your doctor what to do with those medications. Do not decide on your own.
2 to 3 days before	Avoid alcohol and very heavy meals. Arrange for a companion and transportation home.
The day before	Have a light, early dinner. Check what time your fast begins and have your bag with documents and the medical order ready.
The day of the exam	Follow the fasting instructions, take only what is authorized with a sip of water, and arrive at the time you were asked.

One detail many people overlook: ask if the center will provide you with written instructions and what to do if an unexpected issue arises. Having a contact number prevents improvised decisions at 6 a.m.

How many hours of fasting are required and why

For an upper gastrointestinal endoscopy, the usual fast is 6 to 8 hours for solid foods and about 2 hours for clear liquids, although the exact time is determined by your center. The stomach must be empty so the specialist can clearly see the mucosa and to prevent the contents from entering the respiratory tract during sedation. 

Fasting before an endoscopy is not a mere formality. Food residue can hide an ulcer or a small lesion, require repeating the exam, or increase the risk of aspiration pneumonia if you receive sedation. That is why, if you accidentally ate something, say so as soon as you arrive. It is better to reschedule than to take an unnecessary risk.

What to do and what not to do during the fast

• Yes: water in small sips up to the limit you are given, and authorized medications.
• No: coffee with milk, juice with pulp, gum, candy, and smoking. These stimulate gastric secretion or leave residue.

If your exam is in the afternoon, ask if you can have a light breakfast at a certain time. Some centers allow it and others do not, and the difference depends on the time and the type of sedation.

Fasting in diabetics, children, and older adults

In people with diabetes, fasting can cause hypoglycemia, so the times are adjusted and the appointment is usually scheduled for the first thing in the morning. In children, fasting times vary depending on age and whether they drink breast milk, formula, or eat solid foods, and are always determined by the medical team. In older adults, it is advisable to stay well hydrated up to the permitted limit.

Which medications to discontinue and which not to

The practical rule: do not discontinue anything on your own, but do not hide anything either. Anticoagulants and antiplatelet medications usually require prior adjustment, while many medications for blood pressure, heart conditions, or thyroid conditions are normally taken with a sip of water. The decision depends on why you use each medication and whether biopsies will be taken or a procedure performed.

This table is for guidance and does not replace your doctor's instructions:

Type of medication	General guideline
Anticoagulants (warfarin and similar medications)	Almost always require prior planning with the doctor who prescribed them.
Antiplatelet medications (clopidogrel, aspirin)	The decision is made based on cardiovascular risk. Do not discontinue them without authorization.
Anti-inflammatory medications (ibuprofen, naproxen)	Are usually paused a few days before if the doctor instructs it.
Antihypertensives and heart medications	Are generally taken with a little water on the day of the exam.
Insulin and oral hypoglycemic medications	Doses are adjusted due to fasting. Ask for specific instructions.
Antacids and proton pump inhibitors	The specialist may ask you to discontinue them so they do not hide lesions. Discuss it with them.
Iron	Is sometimes discontinued a few days before because it darkens the mucosa and makes visualization difficult. Confirm.

A typical mistake: discontinuing the anticoagulant without informing the doctor who prescribed it. Discontinuing it without a plan can increase the risk of thrombosis, and continuing it without informing the doctor can increase the risk of bleeding. Both extremes can be avoided with a timely call.

What information to provide the doctor before the exam

Before the exam, you must provide your relevant history: medical conditions, allergies, medications, previous surgeries, possible pregnancy, and previous experiences with sedation. This information allows the selection of the appropriate anesthesia, anticipates risks, and helps decide whether it is advisable to perform the study at that time or at another.

Prepare the list in writing. During the consultation, details are forgotten, and those that seem minor are often the ones that change the course of action. Include:

• Heart, lung, kidney, or liver diseases, and sleep apnea.
• Allergies to medications, latex, iodine, or anesthetics, and allergies to eggs or soy if propofol is mentioned.
• Everything you take, with dosages and times, including natural products.
• Previous abdominal surgeries or complications with previous sedations.
• Pregnancy or the possibility of pregnancy, and heart valves or prostheses.
• Removable dental prostheses, loose teeth, or difficulty opening your mouth.

If you have doubts about the duration or whether you will lose the day, check how long a flexible endoscopy takes: the exam itself is usually brief, but the subsequent recovery from the effects of sedation is what lengthens the visit.

Where the anesthesia is applied

This is a common question. In an upper endoscopy, a local anesthetic spray may be applied to the throat, and sedation is administered intravenously, normally through a vein in the arm or hand. That is why it is advisable to arrive in comfortable clothing with wide sleeves. The anesthesia is not applied to the stomach, and the exact type is determined by the medical team according to your case.

Endoscopy in children: what to consider

In minors, the exam is usually performed with sedation or general anesthesia and by a team accustomed to pediatrics. The risks are uncommon but do exist: reactions to sedation, respiratory problems, bleeding, or, very rarely, perforation. Parents should report weight, allergies, respiratory history, and medications, and strictly follow the fasting instructions according to age.

What to bring on the day of the procedure

On the day of the exam, bring your ID, the medical order, your insurance card or authorization, relevant previous exams, and the medication list. Also, go with an adult companion: if you receive sedation, you will not be able to drive or sign important documents in the following hours.

A small bag is enough:

• Documents, order, authorization, and results of previous studies.
• Comfortable and loose clothing, no jewelry, and no nail polish if they ask you to measure oxygen.
• Case for dental prostheses, glasses, or contact lenses.
• A light snack to eat when the doctor authorizes it after the exam.
• A responsible companion for the ride home.

Afterward, plan for a quiet rest. In general, it is recommended to rest for the remainder of the day, not drive, not make important decisions, and gradually return to your diet unless otherwise instructed. There are mild discomforts, such as an irritated throat or a feeling of gas, that subside on their own. If biopsies or additional procedures were performed, the doctor will provide more specific instructions. 

Signs that require you to call and reschedule

Call before going if you have a fever, a severe cough, a cold with difficulty breathing, persistent vomiting, have not followed the fasting instructions, have changes in your medication, or suspect pregnancy. In those cases, having the exam can be risky or useless, and calling in time saves you a lost day and helps the center reassign the slot.

Ask for a new date or consult immediately if any of these cases occur:

• Fever or active respiratory infection in the days leading up to the exam.
• You ate or drank during the fasting period.
• You took an anticoagulant, antiplatelet medication, or anti-inflammatory medication without having consulted.
• Your symptoms worsened: severe pain, vomiting blood, black stools, or difficulty swallowing. This is not expected: go to the emergency room.
• You do not have a companion for the ride home.

Rescheduling is not a failure; it is part of doing the exam properly. If you want to better understand the procedure and its scope, the page on flexible endoscopy explains the technology behind the study. For general context on the technique, you can also consult the Wikipedia entry on endoscopy.

Your next step: today, write down your medications, allergies, and medical conditions on a sheet of paper, and call the center where you will have the exam to confirm the exact fasting hours and whether there will be sedation. With that sheet and that call, you will have resolved 90% of the preparation.

Frequently asked questions

How should I prepare for an endoscopy?

Confirm with your doctor which medications to take or pause, follow the fasting instructions (usually 6 to 8 hours for solids), report allergies and medical conditions, bring documents and the medical order, and go with an adult companion. If you will receive sedation, do not drive or make important decisions that day.

Where do they give you the anesthesia for an endoscopy?

In an upper endoscopy, an anesthetic spray may be applied to the throat and sedation administered intravenously, normally through a vein in the arm or hand. It is not applied to the stomach. The medical team determines the type and dose according to your health and the exam.

How long should I rest after an endoscopy?

If sedation was used, it is customary to rest for the remainder of the day, with a companion, without driving or making important decisions. The diet is resumed gradually when the doctor authorizes it. If biopsies or additional procedures were performed, they may give you more specific instructions.

What risks does an endoscopy in children have?

They are uncommon: reactions to sedation or anesthesia, temporary respiratory problems, mild bleeding, and, very rarely, perforation. They are reduced by following the fasting instructions according to age, reporting allergies and medical history, and having the exam performed by a team with pediatric experience.

Can I take my medications on the day of the endoscopy?

It depends on the medication. Many chronic medications, such as antihypertensives, are taken with a sip of water. Anticoagulants, antiplatelet medications, insulin, and anti-inflammatory medications require prior instructions from the doctor. Do not discontinue or continue anything on your own: discuss it with your doctor a few days before the exam.

What happens if I ate something during the fast?

Tell the staff as soon as you arrive, without hiding it. A stomach with food residue makes visualization difficult and increases the risk of aspiration pneumonia with sedation. Most likely, they will reschedule the exam or adjust the procedure, depending on the time elapsed and what you ingested.