The thought of having a gastroscopy or a colonoscopy can cause some anxiety, but these procedures are incredibly valuable tools for diagnosing and treating conditions of the gastrointestinal (GI) tract. They provide your doctor with a direct view of your digestive system, allowing for accurate diagnoses that other tests might miss.
A successful procedure, however, depends heavily on one thing: proper preparation. Following your doctor’s instructions to the letter is not just a suggestion—it’s essential for ensuring the test is accurate, safe, and effective. Incomplete or poor preparation can obscure the view, leading to a missed diagnosis or the need to repeat the entire process.
This guide will walk you through everything you need to know about preparing for a gastroscopy and colonoscopy, so you can approach your appointment with confidence and peace of mind.
Understanding the Procedures
Before diving into the preparation, let’s quickly clarify what these procedures involve. Both are types of endoscopy, which means a doctor uses a thin, flexible tube with a camera and light (an endoscope) to look inside your body.
- A gastroscopy (or upper endoscopy) examines the upper part of your digestive system: the oesophagus, stomach, and the first part of the small intestine (the duodenum).
- A colonoscopy examines the lower part: the entire large intestine (colon) and rectum.
Your doctor will provide specific instructions tailored to your health and the procedure you are having. This guide offers a general overview of what to expect.
Preparing for a Gastroscopy (Upper Endoscopy)
The preparation for a gastroscopy is relatively straightforward compared to a colonoscopy. The main goal is to ensure your stomach is empty so the doctor has a clear view.
The Key Rule: Fasting
An empty stomach is non-negotiable for a clear and safe gastroscopy. If there is food in your stomach, it can block the doctor’s view and, more dangerously, increase the risk of food entering your lungs during sedation (aspiration).
- Stop Eating: You will need to stop eating solid food for at least six to eight hours before your scheduled procedure.
- Clear Liquids: You can usually drink clear liquids (like water, black tea or coffee without milk, or clear broth) up to two to four hours before the procedure. After that, you must not consume anything by mouth.
- Follow Exact Timings: Your hospital or clinic will give you a precise cut-off time. Adhere to it strictly.
Medication Adjustments
It is crucial to discuss all your medications with your gastroenterologist in Johor Bahru well before your procedure date.
- Routine Medications: Most medications can be taken with a small sip of water on the morning of the procedure. However, always confirm this with your doctor.
- Blood Thinners: Medications like warfarin, clopidogrel, or newer anticoagulants may need to be stopped or adjusted several days before the gastroscopy to reduce the risk of bleeding, especially if a biopsy is taken. Never stop these medications without your doctor’s explicit instruction.
- Diabetes Medications: If you have diabetes, your doctor will provide specific advice on how to manage your insulin or tablets during the fasting period to prevent your blood sugar from dropping too low.
Preparing for a Colonoscopy: The “Bowel Prep”
The preparation for a colonoscopy is more intensive because the entire large intestine must be completely clean. Any remaining stool can hide polyps or other abnormalities, making the procedure less effective. This process is commonly known as “bowel prep.”
The Low-Fibre Diet (A Few Days Before)
Your doctor will likely ask you to switch to a low-fibre (or low-residue) diet for two to three days before your colonoscopy. This helps to reduce the amount of waste in your colon, making the final clean-out easier.
Foods to Eat:
- White bread, white rice, and plain pasta
- Lean meat, poultry, and fish
- Eggs
- Clear broths
Foods to Avoid:
- Whole-grain bread, cereals, and pasta
- Nuts, seeds, and popcorn
- Raw vegetables and fruit with skins or seeds
- Red or purple coloured foods and drinks (these can stain the colon and be mistaken for blood)
The Clear Liquid Diet (The Day Before)
The day before your colonoscopy, you will transition to a clear liquid diet only. This means no solid food at all.
What you CAN have:
- Water
- Clear, pulp-free fruit juices (like apple or white grape juice)
- Clear broth or bouillon
- Black tea or coffee (no milk, cream, or sugar substitutes with colour)
- Clear sports drinks or electrolyte solutions
- Jelly (avoid red, purple, or blue colours)
The Bowel Preparation Solution
This is the most challenging part of the preparation for many people, but it is also the most important. You will be prescribed a strong liquid laxative solution designed to empty your colon completely.
- Timing is Key: The solution is often taken in a “split dose.” You will drink half of it the evening before your procedure and the second half on the morning of your procedure, about four to six hours before your appointment. Studies show this split-dosing method results in a cleaner colon.
- Follow Instructions: The laxative will come with specific mixing instructions. Follow them precisely.
- Stay Near a Toilet: Once you start drinking the solution, you will need to use the toilet frequently and urgently. Plan to be at home and comfortable.
- Tips for Drinking: The taste of the solution can be unpleasant. Here are some tips to make it more tolerable:
- Chill the solution in the refrigerator for a few hours.
- Drink it through a straw placed at the back of your tongue.
- Rinse your mouth with water or mouthwash after each glass.
- Suck on a hard, clear sweet (like a lemon drop) between glasses.
By the end of the prep, your bowel movements should be a clear or yellowish liquid. This is the sign that your colon is clean and ready for the examination.
On the Day of Your Procedure
Whether you are having a gastroscopy or a colonoscopy, there are a few final things to remember.
- Arrange a Ride: You will receive sedation for the procedure, which will make you drowsy and impair your judgment. You will not be allowed to drive, operate machinery, or make important decisions for 24 hours. Arrange for a responsible adult to take you home and ideally stay with you.
- Wear Comfortable Clothing: Choose loose, comfortable clothes to wear to your appointment.
- Bring Your Information: Have your ID, insurance details, and a list of your current medications ready.
Conclusion: Your Effort Makes a Difference
Preparing for a gastroscopy or colonoscopy can feel like a major undertaking, especially the bowel prep for a colonoscopy. However, your diligence and commitment to following the instructions are what enable your specialist to perform a thorough and accurate examination. A clean digestive tract allows the gastroenterologist to detect polyps, identify sources of bleeding, diagnose diseases, and ultimately provide you with the best possible care.
Think of the preparation not as a hurdle, but as the first and most crucial step in taking control of your digestive health. Your effort directly contributes to the success of the procedure and the clarity of your results.