Cholestyramine is used to lower high levels of cholesterol in the blood, especially low-density lipoprotein (LDL) ("bad" cholesterol).

Cholestyramine is also used to treat itching caused by a blockage in the bile ducts of the gallbladder.

Cholestyramine may also be used for purposes not listed in this medication guide.

You should not use cholestyramine if you have a blockage in your stomach or intestines.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Although cholestyramine is usually taken once or twice per day, cholestyramine may be taken up to 6 times per day. Carefully follow your doctor's dosing instructions.

Mix the cholestyramine powder with at least 2 to 6 ounces of water or other non-carbonated beverage. You may also mix the powder with a brothy soup, crushed pineapple, or applesauce. Measure the powder using the scoop provided with your medication. Do not use any other scoop or measuring cup to measure your cholestyramine dose.

Use cholestyramine regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

Cholestyramine can affect the surfaces of your teeth. Sipping the cholestyramine/liquid mixture slowly or holding the liquid in your mouth for too long may result in tooth discoloration, enamel erosion, or tooth decay. Be sure to brush your teeth regularly while you are using this medicine.

Drink extra fluids to prevent constipation while you are taking cholestyramine.

While using cholestyramine, you may need frequent blood tests.

Cholestyramine is only part of a complete program of treatment that may also include diet, exercise, and weight control. Follow your diet, medication, and exercise routines very closely.

Store at room temperature away from moisture and heat.

You should not use cholestyramine if you are allergic to it, or if you have:

• a blockage in your biliary tract.

Tell your doctor if you have ever had:

• chronic constipation;

• a thyroid disorder;

• diabetes;

• kidney disease;

• liver disease; or

• coronary artery disease (clogged arteries).

This medicine may contain phenylalanine. Talk to your doctor before using cholestyramine if you have phenylketonuria (PKU).

Taking cholestyramine can make it harder for your body to absorb certain vitamins. Your doctor may recommend you take a vitamin supplement.

Tell your doctor if you are pregnant or breastfeeding.

You may have an even greater need for vitamin supplements during pregnancy or while you are breast-feeding a baby. Follow your doctor's instructions about taking vitamin supplements during treatment with cholestyramine.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include severe stomach pain or constipation.

Avoid taking other medications at the same time you take cholestyramine. Wait at least 1 hour before or 4 to 6 hours after taking cholestyramine before you take any other medications.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Cholestyramine may cause serious side effects. Call your doctor at once if you have:

• ongoing or worsening constipation;

• severe stomach pain;

• blood in your urine;

• black, bloody, or tarry stools; or

• easy bruising, unusual bleeding.

Side effects such as constipation may be more likely in older adults.

Common side effects of cholestyramine may include:

• mild constipation, diarrhea;

• stomach pain, nausea, loss of appetite;

• bloating or gas;

• irritation of your tongue; or

• itching or irritation around your rectal area.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your current medicines. Many drugs can affect cholestyramine, especially:

• birth control pills or hormone replacement therapy;

• digoxin (digitalis);

• a diuretic or "water pill";

• penicillin G;

• phenobarbital;

• phenylbutazone;

• propranolol;

• spironolactone;

• tetracycline;

• thyroid medication such as levothyroxine; or

• warfarin (Coumadin, Jantoven).

This list is not complete. Other drugs may interact with cholestyramine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.