What is it used for?

• High blood cholesterol levels (hypercholesterolaemia).
• Preventing coronary heart disease in men aged 35 to 59 years who have high blood cholesterol (primary hypercholesterolaemia) that has not responded to a cholesterol-lowering diet or other measures.
• Relieving itching caused by partial blockage of the bile ducts (biliary obstruction), or a form of liver disease involving the bile ducts (primary biliary cirrhosis).
• Relieving diarrhoea associated with:- Crohn's disease; surgical removal of part of the intestine (ileal resection); removal of the nerve supply to the gut (vagotomy); decreased nerve supply to the gut due to diabetes (diabetic vagal neuropathy); or radiation treatment.

How does it work?

• Questran sachets contain the active ingredient colestyramine (previously spelt cholestyramine in the UK), which is a type of medicine called a bile acid sequestrant. (NB. Colestyramine is also available without a brand name, ie as the generic medicine.)
• Colestyramine is not absorbed into the bloodstream. It works in the intestines, where it binds to bile acids.
• Bile is a fluid that is produced by the liver. It is released into the intestine through the bile duct as part of digestion. Bile contains substances called bile acids, which the liver makes from cholesterol in the blood. Bile acids aid the digestion of fats consumed in the diet. Following digestion, the bile acids are reabsorbed into the bloodstream and are then returned to the liver.
• Colestyramine binds to the bile acids in the intestine and prevents them being reabsorbed into the bloodstream. Instead, they pass through the intestine with the colestyramine and are excreted in the faeces. This triggers the liver to produce more bile acids from the cholesterol in the blood, which lowers the level of cholesterol in the blood.
• High cholesterol levels increase the risk of heart disease by clogging and narrowing the arteries (atherosclerosis). Colestyramine is used to lower cholesterol levels and thus reduce the risk of hardening of the arteries and the problems this can cause. It may be used on its own, or in combination with other cholesterol-lowering medicines.
• Medicines are used to lower high cholesterol levels when a low-cholesterol diet and exercise regime have not done this sufficiently. However, it is important to continue to follow your cholesterol-lowering diet while taking this medicine. Discuss this with your doctor.
• Colestyramine is also used to treat people who have an obstruction of the bile duct, or a form of liver disease involving the bile ducts. A blockage in the bile duct can cause bile acids to build up in the blood and then be deposited in the skin. This can make the skin itchy. Colestyramine reduces the levels of bile acids in the blood and so reduces the amount of excess bile acids deposited in the skin. This stops the itching associated with these conditions.
• A further use of colestyramine is in the relief of diarrhoea associated with various conditions described below, in which bile acids are not properly absorbed from the intestine. Colestyramine relieves the diarrhoea by binding to the unabsorbed bile acids.

Use with caution in

• Children with inherited high blood cholesterol (familial hypercholesterolaemia).
• Diabetes (each sachet of Questran contains 3.79g of sucrose).

Not to be used in

• Total blockage of the bile duct (total biliary obstruction).
• This medicine is not recommended for children under six years of age.
• This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

• Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
• The safety of this medicine for use during pregnancy or breastfeeding has not been established. The medicine is not absorbed into the bloodstream, but it may cause deficiences in fat soluble vitamins with prolonged use. For this reason, it should be used with caution in women who are pregnant or breastfeeding, and only if the potential benefit to the mother outweighs any possible risks to the baby. Seek medical advice from your doctor.

Label warnings

• Dissolve or mix this medication with water before taking.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.

• Constipation.
• Diarrhoea.
• High levels of chloride in the blood resulting in high acid levels in the blood (hyperchloraemic acidosis).
• Increased tendency to bleed due to vitamin K deficiency.
• Blockage (obstruction) of the intestines.

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

• It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.
• Colestyramine may interfere with the absorption of other medicines from the gut if they are taken at the same time at this medicine. To avoid this, other medicines should be taken at least one hour before or four to six hours after taking colestyramine.

If you are taking any of the following medicines your treatment should be monitored, as colestyramine may alter the effects of these medicines, even if the above advice regarding timing of doses is followed:

• acarbose
• amiodarone
• anticoagulants, eg warfarin
• glipizide.

Colestyramine significantly decreases the effect of leflunomide and should not given to people taking leflunomide unless it is needed to wash-out the leflunomide.

Colestyramine is not recommended for use in combination with raloxifene.

References:

https://www.netdoctor.co.uk/medicines/heart-blood/a7436/questran-colestyramine/

https://www.verywellhealth.com/cholestyramine-overview-1944663

https://www.medicines.org.uk/emc/product/5715/pil

https://www.medicines.org.uk/emc/product/911/smpc

https://www.webmd.com/drugs/2/drug-3334/questran-oral/details

https://www.rxlist.com/questran-drug.htm