Cholestyramine — what it does and how to use it safely

If your doctor mentioned cholestyramine, you probably want straight answers: what it treats, how to take it, and what to watch for. Cholestyramine is a bile acid sequestrant — it binds bile acids in the gut. That helps lower LDL cholesterol and can stop bile-acid related diarrhea or itching from liver problems. It’s a powder you mix with water or juice, not a pill.

How it works and common uses

Cholestyramine traps bile acids so they leave the body in stool instead of being reabsorbed. Your liver then pulls more cholesterol out of the blood to make new bile acids, which lowers LDL levels. Doctors also use it to treat bile-acid diarrhea and to relieve itching (pruritus) in some liver conditions. Expect results on cholesterol in weeks; relief from diarrhea or itching can be sooner.

Practical dosing and taking it right

Typical adult doses start around 4 grams once or twice daily, mixed into a glass of water or juice. Some people need more, up to commonly recommended daily totals, but follow your prescriber’s instructions. The powder can be gritty — stir well and drink quickly. Rinse the glass and drink a bit more water so you don’t leave residue in the cup.

Timing matters because cholestyramine binds other medicines and some vitamins. To avoid problems, take other meds at least 1 hour before or 4–6 hours after cholestyramine when possible. For drugs that are critical or have narrow dosing ranges (like warfarin, levothyroxine, or certain antiepileptics such as phenytoin), check with your prescriber or pharmacist for exact timing and monitoring needs.

Common side effects are usually mild: constipation, bloating, gas, and abdominal discomfort. Drinking more fluids, increasing fiber slowly, and using a stool softener can help if constipation starts. Because cholestyramine can reduce absorption of fat-soluble vitamins (A, D, E, K), your doctor may check levels or recommend supplements if you use it long-term.

Tell your provider if you’re pregnant, breastfeeding, or taking multiple medications. Some people can’t use cholestyramine — for example, if they have complete biliary obstruction or a history of severe constipation or bowel blockage. If you notice severe stomach pain, persistent vomiting, or signs of a blockage, seek care right away.

Finally, keep a list of all your medicines and show it to your pharmacist. That simple step helps avoid interactions and ensures any necessary blood tests or dose adjustments happen on time. If something feels off after starting cholestyramine, call your healthcare team — small changes often fix issues quickly.