Bowel preparation before colonoscopy

What is in the box

• Two bottles of 177 ml each, lemon flavour. Each bottle is one dose. You need both doses.
• The liquid is very strong. It must be mixed with drinking water before you drink it. Never drink it straight from the bottle.
• A leaflet. Read it before you start.
• Check the label. Each bottle should say: sodium sulphate 17.5 g, potassium sulphate 3.13 g, magnesium sulphate 1.6 g. If your box looks different or lists other contents, it is a different product. Ask before you use this sheet.

Your timetable

1. 5 days beforeStop iron tablets and fibre powders such as isabgol, unless your centre gave a different number of days. Tell the doctor now if you take a blood thinner, diabetes medicines, blood pressure tablets or tablets that make you pass more urine, or if you are pregnant or have kidney disease, heart failure, gout or fits. Do not stop a blood thinner on your own.
2. The day before, morningA light breakfast is allowed: white bread, plain white rice or a boiled egg. No vegetables, fruit, nuts, seeds or whole grains.
3. After that breakfastClear liquids only, no solid food and no milk until the colonoscopy is over. Drink plenty.
4. The evening before: dose 1Pour one whole bottle (177 ml) into a clean jug. Add about 300 ml of cool drinking water, to make about half a litre (475 ml) in all. An empty half-litre water bottle is an easy measure. Drink all of it. Then drink about 1 litre of plain water over the next hour. If the leaflet in your box gives a different amount of water, follow the leaflet.
5. The morning of the test: dose 210 to 12 hours after dose 1, mix and drink the second bottle in the same way, followed by about 1 litre of water over the next hour. Start it 4 to 6 hours before the colonoscopy.
6. At least 2 hours before the testFinish the dose and the water, then stop all drinking. Some centres ask for a longer gap: use the time they gave you.

What to expect

• Loose motions begin within a few hours of the first dose. Stay close to a toilet.
• By the end, what you pass should be watery and clear or pale yellow, like urine. If it is still brown or has solid pieces on the morning of the test, tell the endoscopy centre before you leave home.
• Bloating, nausea and cramps are common and settle.

To make it easier

• Chill the mixed dose and drink it through a straw.
• If you feel sick, stop for 30 minutes, then start again slowly.
• If you are bloated after dose 1, wait until it settles before you take dose 2.
• Put petroleum jelly around the back passage before the motions start. Use soft tissue and pat, do not rub.

Your other medicines

• Do not swallow any tablet in the hour before you start each dose. It may pass through without being absorbed. Some medicines need a bigger gap, 2 hours before and 6 hours after each dose: digoxin, and antibiotics such as doxycycline, ciprofloxacin and levofloxacin. Ask the pharmacist.
• Take blood pressure and heart tablets as your doctor advised for this day. Ask in advance. Do not take painkillers such as ibuprofen or diclofenac during the preparation: with the fluid loss they can harm the kidneys.
• If you take a weekly injection for diabetes or weight (semaglutide, tirzepatide, dulaglutide), tell the endoscopy centre. They may ask for a longer time on clear liquids.
• If you have diabetes, a day on clear liquids changes your tablets and insulin. Ask your doctor for a written plan, or use our diabetes medicines before a procedure tool. Medicines whose names end in -gliflozin (dapagliflozin, empagliflozin, remogliflozin and others, alone or in a combination tablet) are usually stopped 3 days before. Check your sugar more often and use sweet clear liquids if it drops.