What is a Colonoscopy?
  • It is an examination of your large bowel.
  • You will have an injection to make you sleepy so you will be comfortable during the examination.
  • A long thin flexible tube with a light on the end is introduced into the large bowel via the back passage. This allows the doctor to look into the large bowel to see what might be causing your problems.
Preparation for the examination
  • For this examination to be successful your bowel must be as empty as possible.
  • As part of your preparation you will be given a laxative. See the separate instructions. It is very important to follow these instructions carefully.
  • You can continue to take any medicines or pills as normal, except iron pills or medicines that make you constipated e.g. Codeine Phosphate, Imodium, Iomotil (stop seven days before the procedure).
  • If you are taking warfarin, aspirin or clopidogrel, please contact our clinical team by phoning the hospital switchboard on 0207 272 3070 and ask for bleep number 2711.
On arrival at hospital
  • Please go to the Day Treatment Centre reception, level 3.
  • There a nurse will check your blood pressure and pulse as well as answer any questions you may have.
  • If you are allergic to any medication please tell the nurse.
  • The doctor performing the test will explain the procedure and ask you to sign a consent form to confirm that you understand the examination and agree to go ahead with it.
What does the examination involve?
  • First of all you will be given an injection of sedative into a vein in your hand to make you relaxed. This may make you feel sleepy too, but for most patients it induces sleep after the examination, making it a hazy memory.
  • Then while you are lying comfortably on your left side the doctor will gently pass a small flexible tube into the large bowel via the back passage.
  • Some air will be passed into the bowel to expand it so the bowel lining can be seen more clearly. This may give you some discomfort, but it will not last long.
  • Air that has been passed up into the bowel will obviously have to come out again as wind. Please do not worry about this, it is quite normal.
  • You may feel as if you want to go to the toilet, but as the bowel is empty you do not need to worry about it actually happening.
  • A biopsy (sample of the bowel lining) may be taken during the examination to be sent to the laboratory for further tests. You cannot feel this.
  • The examination lasts about 30 minutes.
  • Afterwards the tube is removed quickly and easily.
After the examination
  • You will need to rest for at least 30 minutes, and once recovered you may eat and drink as normal.
  • You may still have a little wind.
  • The doctor will tell you the result of the test before you go home. Any biopsy result will take longer.
Going home
  • You must have a friend or relative to collect you and accompany you home.
  • You must not drive, drink alcohol or operate machinery (including a kettle) for 24 hours following the sedative.
  • You may notice that your bowels do not return to normal until a few days following the procedure.
Are there any significant risks?

This test is very safe, but very rarely there can be a problem, for example:
  • Perforation - this is a small tear in the wall of the colon. This may not need treating at all or it may require repairing with surgery, in which case you will need to stay in hospital.
  • Bleeding - occasionally when a biopsy (sample) is taken from the bowel lining, there may be a little bleeding. If this does not stop within 24 hours please contact your GP.
Any further questions?

Please phone us, we will be happy to help.

If you have a question about your appointment time and/or how to change it, phone our admin team on 0207 288 3822.

If you have a question about your procedure or your medications, contact our clinical team by phoning the hospital switchboard on 0207 272 3070 and ask for bleep number 2711. Alternatively, phone your GP or NHS Direct on 0845 46 47.
Last updated08 Mar 2016
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