A bile-acid sequestrant
Colestyramine
A powder mixed with water or juice that lowers cholesterol by binding bile acids in the gut; it can cause constipation and bloating and can reduce the absorption of other medicines.
What is Colestyramine?
Colestyramine is a bile-acid sequestrant taken as a powder mixed with water or juice to lower cholesterol, and it is also used for certain types of diarrhoea and itching. It works in the gut by binding bile acids so they are removed, which prompts the liver to use up cholesterol making more. Because it can bind other medicines, you should take them well apart from colestyramine, and it commonly causes constipation and bloating.
Education and reference only. This is a plain-language guide to Colestyramine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Colestyramine is a bile-acid sequestrant used in the UK to lower cholesterol, and also to relieve diarrhoea caused by too much bile reaching the bowel (for example after gallbladder surgery or in certain bowel conditions) and the itching that can come with some liver conditions. It is taken as a powder that is mixed with water, juice or another fluid and drunk, rather than as a tablet. It is not absorbed into the body but works locally in the gut, which is why its main downsides are bowel-related and its main practical issue is how it affects other medicines.
How it works
Bile acids are made by the liver from cholesterol and released into the gut to help digest fats; normally most are reabsorbed and recycled. Colestyramine binds bile acids in the gut and carries them out in the stools instead of letting them be reabsorbed. To replace the lost bile acids, the liver pulls more cholesterol from the blood to make new ones, which lowers blood cholesterol. The same binding action removes excess bile that can cause diarrhoea, and helps with itching linked to bile build-up.
Company & origin
Originated / developed by: Long-established medicine; Questran is marketed in the UK by Bristol-Myers Squibb..
Colestyramine is a bile-acid sequestrant that has been used for many years to lower cholesterol and to relieve certain types of diarrhoea and itching.
What it treats
Conditions Colestyramine is used for
Practical use
How to take Colestyramine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Mix the powder thoroughly with water, juice or another suitable fluid and drink it; never take it dry.
- Take any other medicines at least an hour before, or several hours after, colestyramine, as it can bind them and reduce their absorption.
- Drink plenty of fluids and aim for enough fibre, as constipation and bloating are common.
- Take it regularly and long-term, alongside a healthy diet, as it works in the background on your cholesterol.
- Ask your team about fat-soluble vitamin (A, D, E and K) supplements if you are taking it for a long time.
- Tell your pharmacist about all your medicines, so the timing can be planned to avoid interactions.
Weighing it up
Advantages & disadvantages of Colestyramine
Advantages
- It lowers cholesterol without being absorbed into the body, which suits some people who cannot take other medicines.
- It can be used safely in situations such as pregnancy, where many cholesterol medicines are avoided.
- It also relieves bile-related diarrhoea and the itching of certain liver conditions.
Disadvantages
- It commonly causes constipation, bloating and wind, which some people find hard to tolerate.
- It can reduce the absorption of other medicines, so careful timing is needed.
- It is a powder that must be mixed and drunk, which is less convenient than a tablet, and long-term use may need vitamin supplements.
Practical use
Good to know
The most important practical point is that colestyramine can bind other medicines in the gut and reduce how well they are absorbed. To avoid this, take your other medicines at least an hour before, or several hours after, colestyramine. It is a powder that must be mixed thoroughly with water, juice or another fluid before drinking — it is not swallowed dry. It commonly causes constipation, bloating and wind, which can often be eased with plenty of fluids, fibre and, if needed, advice from your pharmacist. With long-term use it can reduce the absorption of fat-soluble vitamins (A, D, E and K), so your team may recommend supplements. It works in the background, so you will not feel a day-to-day difference.
Who should not take it / use with caution
- People with a complete blockage of the bile ducts, where bile cannot reach the gut.
- People with severe constipation or certain bowel problems, in whom it is used with caution.
- It is not suitable when blood triglyceride levels are very high, as it can raise them further.
- Anyone who has had a serious allergic reaction to colestyramine.
Monitoring
- Blood fat (lipid) levels to check the cholesterol-lowering effect.
- Reviewing bowel symptoms such as constipation, and the response if it is being used for diarrhoea.
- Considering fat-soluble vitamin levels and clotting (vitamin K) with long-term use.
Side effects
- Constipation, which is the most common effect.
- Bloating, wind and tummy discomfort.
- Nausea and, in some people, a reduced appetite.
- With long-term use, reduced absorption of fat-soluble vitamins (A, D, E and K).
Key interactions
- It can bind and reduce the absorption of many medicines (including some heart, thyroid, water and blood-thinning medicines), so other medicines are taken well apart from it.
- It can reduce absorption of fat-soluble vitamins, which may need to be supplemented.
- Tell your prescriber and pharmacist about all your medicines so the timing can be planned.
Available as: Oral powder in sachets, mixed with water or juice before drinking.
Answers
Colestyramine: frequently asked questions
How does colestyramine lower cholesterol?
It works in the gut by binding bile acids, which are made from cholesterol, so they are removed in the stools instead of being reabsorbed. To replace them, the liver pulls more cholesterol from the blood to make new bile acids, which lowers blood cholesterol.
Why do I need to take my other medicines at a different time?
Colestyramine can bind other medicines in the gut and stop them being absorbed properly. To avoid this, take your other medicines at least an hour before, or several hours after, colestyramine, and check the timing with your pharmacist.
How do I take colestyramine?
It is a powder that must be mixed thoroughly with water, juice or another suitable fluid and then drunk. It should never be taken dry. Mixing it well and drinking plenty of fluids also helps reduce bloating.
Does colestyramine cause constipation?
Yes, constipation is the most common effect, along with bloating and wind. Drinking plenty of fluids and eating enough fibre can help, and your pharmacist can advise if it becomes troublesome.
Will I need vitamin supplements?
With long-term use, colestyramine can reduce the absorption of fat-soluble vitamins (A, D, E and K), so your team may recommend supplements. This is more of a concern with prolonged treatment than with short-term use.
The wider class
About Bile-acid sequestrants
Colestyramine belongs to the bile-acid sequestrants class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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