Colestyramine (Questran, Questran Light, LoCholest, Colestid, Prevalite)

Colestyramine is an exchange resin in powder form, mixed into water and drunk. It is not absorbed from the bowel and does not enter the blood; as it passes down the bowel it catches the bile that is present in excess and causes it to be passed out with the stool. In this way it brings about the excretion of excess bile acid.

It is used most often to lower high cholesterol, to stop the diarrhoea that follows gall bladder surgery, to stop the severe itching in the cirrhosis called primary biliary cirrhosis, which runs its course with severe stasis of bile, and as an antidote in poisoning by digitalis, the drug used in heart failure.

How it is used

One 4-gram sachet of powder should be taken morning and evening, thoroughly mixed into water. Because this drug can reduce the absorption of other drugs, it is best taken between meals. For high cholesterol one to four sachets a day may be taken; it can go as high as six doses a day, but that dose has never yet been reached.

What are the side effects?

It can increase constipation and can aggravate constipation that was already there, which makes it of particular importance in the elderly. For this reason there can be severe cramping abdominal pain, as in obstruction of the bowel. The drug is begun at a low dose and the dose raised over time, and constipation can be prevented in this way. If constipation develops, the drug can be stopped until it settles.

Among its very uncommon side effects, wind, belching, nausea, abdominal pain, heartburn and reduced appetite may be seen. These side effects go away either with time or on reducing the dose.

Take care

The drug should be taken with plenty of water. Holding the drug in the mouth for a long time can cause discolouration of the teeth and erosion or loss of enamel.

Colestyramine binds to other drugs and prevents or delays their effects. For this reason colestyramine should not be taken at the same time as other drugs. Other drugs should be taken an hour before colestyramine or four hours after it.

With long-term colestyramine treatment, the absorption of the fat-soluble vitamins A, D, E and K is reduced.