Neurodiversity information for parents and young people
A colonoscopy or sigmoidoscopy is done to have a look inside the bowel. Both are a type of endoscopy. For this, the bowel must be completely empty.
You must prepare properly
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7 days before
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2 days before
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1 day before​​​​​​​
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Day of morning appointment
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Day of afternoon appointment
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About bowel preparation
Bowel prep involves:
- taking the medicines Picolax and senna (both laxatives) to make you poo
- cutting down on how much fibre you eat
- stopping all food in the last few hours beforehand.
Important instructions
The instructions given below are very important. If you do not stick to them, we will probably have to cancel the procedure because we will not be able to see inside your bowel clearly.
Effect of bowel preparation
The laxatives will cause repeated bowel movements and eventually diarrhoea.
These effects can start at any time after taking the laxatives. The urge to open your bowels can be sudden, giving you little time to reach a toilet. So, it is a good idea to stay within easy reach of a toilet.
The laxatives may also cause nausea, stomach cramps and bloating.
Very rarely, patient have a severe reaction to the laxatives.
It is sensible to have a supply of the drinks you will need before starting your laxatives. See box A, below.
7 days before the endoscopy
Increase how much fluids you drink to 200 mls (one large cup) every hour. This is to make the laxatives work better.
Start eating only low-fibre food (see box B).
Cut down alcohol to no more than one small glass of wine or one small bottle of beer per day.
2 days before the endoscopy
Stop solid foods 24 hours before you start taking the laxatives. Instead, drink only clear fluids (see box A). Continue to drink 200 mls (one large cup) every hour. Do not eat any solid food until after the endoscopy.
Do not drink just water. It is important you drink sugary drinks for the energy and savoury drinks for the salt. Otherwise, you may feel weak or dizzy and you may even faint.
1 day before the endoscopy
When you start this depends on what time your endoscopy is booked for. The tables, below, set out the details.
Continue to avoid any solid food and drink plenty of clear fluids (see box A).
Morning endoscopy
(8am to 12.45 appointments)
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Day before |
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| midday |
Take all 10 senna tablets. Drink at least one additional litre of clear fluids (see box A). |
| 2pm |
Take the first dose of Picolax (see box C). |
| 8pm | Take the second dose of Picolax. |
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Day of appointment |
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| 4 hours before | Stop all fluids apart from sips of water. |
| 2 hours before | Stop drinking water until after endoscopy. |
Afternoon endoscopy
(1pm to 5.30pm appointments)
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Day before |
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| 3pm |
Take all 10 senna tablets. Drink at least one additional litre of clear fluids (see box A). |
| 7pm | Take the first dose of Picolax (see box C). |
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Day of appointment |
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| 7am | Take the second dose of Picolax. |
| 4 hours before | Stop all fluids apart from sips of water. |
| 2 hours before | Stop drinking water until after endoscopy. |
Box A
| Clear fluids | Avoid |
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Box B
| Low-fibre food you can eat |
Foods to avoid |
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| Cereals | |
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| Dairy | |
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milk, cream
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| Soup | |
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| Protein | |
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| Fruit and vegetables | |
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| Bread and starchy food | |
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| Preserves | |
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| Snacks and puddings | |
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biscuits containing bran |
Box C
| How to take laxatives |
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| • Empty one packet of Picolax into 150ml cold water. • Stir until dissolved. • The Picolax may become hot when mixed with water. • Allow it to cool before drinking it. • You may add squash (without ‘bits’) or ice if you wish. |
Contact information
Endoscopy nurses helpline
Telephone:
020 8934 6614 (2pm to 4pm only)