A colonoscopy is a highly effective technique for the early detection of signs of colorectal cancer such as inflammation, tumours, and small growths (polyps). However, its accuracy depends on the preparation done before the procedure.
Thorough bowel preparation is crucial for a successful colonoscopy. A clean colon allows doctors to
visualise the entire lining clearly, enabling the detection and removal of abnormalities before they
can develop into serious complications. Inadequate preparation can lead to inaccurate results and
necessitate a repeat or rescheduled procedure.
Several days before the colonoscopy, patients will receive specific instructions for bowel
preparation. It is essential to carefully read and adhere to these instructions to ensure effective
cleansing.
Thorough bowel preparation is crucial for a successful colonoscopy. A clean colon allows doctors to Preparation for a colonoscopy may start a week before the procedure. Here is a general step-by-step guide on how to prepare for a colonoscopy:
- Consult a doctor to discuss medical history and medications
- Adjust medications (e.g., blood thinners, supplements) under medical advice
- Begin a low-fibre diet
- Stay hydrated to facilitate bowel preparation
- Switch to a clear-liquid diet
- Follow instructions on taking bowel preparation medication (e.g., timing and dosage)
- Fast for at least 6–8 hours before the procedure.
- Ensure an empty bowel for the procedure.
Patients are typically required to consume a laxative the day before a colonoscopy. This helps cleanse the colon thoroughly, ensuring a clear view during the procedure. The doctor will recommend a specific laxative based on the patient's individual medical history, preferences, and tolerance.
Some doctors recommend splitting the laxative dose to improve tolerability. This involves taking half of the prescribed dose in the evening and the rest 6 hours before the procedure. This approach can help minimise the solution's initial impact and make the overall process more manageable.
Aside from the split method, here are other ways to make the bowel prep solution easier to drink:
- Drink the solution in small sips over time
- Use a straw to reduce the unpleasant taste
- Mix it with a sports drink, ginger or lime
- Take it well chilled
- Suck on a lemon slice or candy after drinking it
Changes to the diet should be started a few days beforehand to help improve the chances of a successful procedure. Doctors usually recommend light, low-fibre food as they are easy to digest and leave the system quickly. High-fibre, fried and fatty food, on the other hand, should be avoided as they take longer to digest.
- White bread (no spread)
- White rice/porridge
- Noodles
- Eggs
- Lean meat (chicken/fish)
- Canned fruits, without skin
- Well-cooked vegetables without skin
- Seeds, nuts, or popcorn
- Tough meat
- Whole grains/oats
- Raw vegetables
- Fruit with seeds or peel
- Dairy products
Proper hydration is also crucial during bowel preparation for colonoscopy. Dehydration can lead to headaches, dizziness, fatigue, and even more serious complications. Staying hydrated helps the bowel prep solution work more effectively and makes patients feel more comfortable during the process.
- Water
- Coffee/tea without milk
- Clear sodas
- Clear broths
- Red, blue or purple liquids
- Milk
- Juices with pulp
- Alcohol
Certain medications may need to be adjusted before a colonoscopy, as they can interfere with the
procedure or increase the risk of complications. Patients should inform their doctor about their
medication, preferably one to two weeks before the procedure. This allows the doctor to decide
whether to adjust the dose or temporarily stop the medications.
Common medications that need adjustment include:
- Medications for high blood pressure
- Diabetes medications
- Blood thinners such as aspirin and warfarin
- Iron supplements
It is important to note that this information is for general guidance only and should not be considered medical advice. Any adjustments to your medication regimen must be made under the direct supervision of your doctor.
Preparing for a colonoscopy involves more than just bowel preparation. Here is a list of what to bring and wear on the day of the colonoscopy to ensure a smooth experience.
What to bring:
- Identification: NRIC, Birth Certificate (if under 15 years old), Work Permit, or Passport (for foreigners),
- For Civil Servants/SAF Personnel: Civil Service Card (CSC) or Medical Benefits Identification Memo (MBIM).
- For Employer-Sponsored Hospitalisation Coverage: Hospitalisation Identity Card or Letter of Guarantee.
- For Work Pass Holders: Valid work pass, CPF membership card (if applicable), or employer’s letter (if required).
- For MediSave Payment: NRIC of the MediSave account holder.
- For Blood Donors: Blood Donor or Blood Donor Nominee Card.
What to wear:
- Comfortable, loose clothing
- Comfortable shoes
- No jewellery
- No make-up, lotions, perfume
- No nail polish
A typical colonoscopy procedure takes approximately 20–40 minutes to complete. Following the procedure, patients are typically monitored in a recovery area while the effects of sedation wear off. Nurses carefully observe patients for any potential complications, such as bleeding or excessive discomfort. Once the effects of sedation have subsided and the doctor has cleared the patient for discharge, they can return home.
Patients may experience some mild side effects as their body recovers from a colonoscopy. These side effects are only temporary and should resolve within a day or two. Common side effects include:
- Mild cramping or bloating
- Grogginess from sedation
- Mild bleeding
- Bloating and gas
Recovery time after a colonoscopy varies from person to person. While most patients recover a day after, some may take slightly longer especially if polyps were removed. Following a colonoscopy, it is generally recommended to adopt a light and easily digestible diet.
Suitable food choices may include:
- Mashed or baked potatoes
- Skinless chicken breast
- White toast
- Scrambled eggs (without added seasonings or dairy products)
- White rice
- White fish
- Yoghurt
- Plain crackers (lightly salted or unseasoned)
While colonoscopy is a safe screening procedure, some possible complications may still occur. Warning signs that require immediate medical attention include:
- Severe abdominal pain
- Excess or prolonged bleeding
- High fever or chills
If you experience any of these symptoms, please contact your doctor immediately.
Most patients can resume normal activities, including returning to work, the day after a colonoscopy, provided they are feeling well.
Failure to adhere to the prescribed bowel cleansing instructions will compromise the colonoscopy results. As such, the procedure will likely need to be repeated or rescheduled.
Yes, alternative bowel preparation options are available for patients with allergies or intolerances to standard solutions.