Cholestyramine Is a Bile Acid Resin

Cholestyramine is a cholesterol-lowering drug that belongs to the bile acid resin class of medications. Studies have shown that cholestyramine mainly lowers LDL cholesterol by about 15%. Cholestyramine does not appear to positively impact other aspects of your lipid profile but may increase triglyceride levels in some instances.

Cholestyramine has also been shown to slow the progression of the development of atherosclerosis in a couple of studies. However, it has not been shown to prevent death or disability due to cardiovascular disease. 

Cholestyramine was first approved for use by the Food and Drug Administration in August of 1973 under the brand name, Questran. Since its initial approval, it has also been available under the trade names Prevalite, Locholest, and others.

How Does Cholestyramine Work?

Cholestyramine binds to bile acids in the small intestine, preventing their reabsorption. Bile acids are derived from cholesterol and are needed to help with the digestion of fats consumed in your diet. When cholestyramine binds to bile acids, they become depleted and will not be reabsorbed. To make more bile acids, cholesterol will be removed from the bloodstream and converted into bile acids. This activity lowers your cholesterol levels.

How Should You Take Cholestyramine?

You should take cholestyramine as directed by your healthcare provider. Cholestyramine is available in a powdered form, packaged into small, single-dose packets or in a larger container.

Your healthcare provider may start you on smaller doses and increase your dose based on your response to the medication and side effects. The recommended starting dose is one scoopful or packet (4 grams cholestyramine) once or twice a day. This may be increased to up to six doses a day. The dose should be mixed with at least 2 ounces of water, a fruit juice (with or without pulp), applesauce, a thin soup, or other beverage before consuming. You should ingest the entire contents of the drink containing cholestyramine to get the full dose of the medication. Cholestyramine should be taken with a meal.

Who Shouldn’t Take It?

Due to its components, there are some instances where cholestyramine should not be taken. These would include:

• Individuals who have previously had an allergic reaction to cholestyramine or any of its components should not take cholestyramine. 
• Anyone who has been diagnosed with a biliary obstruction, where bile acids are not secreted into the small intestine.

Conditions That Need to Be Monitored

If you are taking cholestyramine, your healthcare provider may need to monitor you more closely if you have certain medical conditions that could be aggravated by taking the medication. If you have any of the following conditions below, your healthcare provider may decide to start you on cholestyramine but will need to monitor you to determine whether or not taking cholestyramine will be potentially harmful to you. These medical conditions include:

• High triglyceride levels. Cholestyramine has been shown to increase triglyceride levels in studies. If you have high triglycerides, your healthcare provider will monitor your levels to ensure that they do not become too elevated.
• Having chronic constipation. Cholestyramine may worsen this condition if you suffer from constipation.
• Pregnancy. There have not been extensive studies examining the effectiveness and safety of cholestyramine in pregnant women. Since this drug can decrease the absorption of some vitamins, some components of prenatal vitamins may not be effective while taking cholestyramine. Your healthcare provider will make the decision whether or not you should take this drug.

Side Effects 

Constipation is the most commonly noted side effect when taking cholestyramine. This usually goes away with continued treatment. Your healthcare provider may decide to lower your dose or give you a medication to treat your constipation if the side effects become too bothersome. Other common side effects include:

• Bloating
• Flatulence
• Nausea
• Belching
• Vomiting
• Abdominal pain and discomfort

Other side effects have been reported due to prolonged use of cholestyramine. Increased likelihood of bleeding may be noted over time due to decreased Vitamin K. Additionally, changed in liver enzymes and erosion of tooth enamel may occur due to prolonged drinking of the product or holding the product your mouth.

Interacting Medications 

The following drugs may interact with cholestyramine by decreasing the amount of the medication absorbed into your blood. Manufacturer recommends not to take any other medications or supplements at least one hour before or 4 to 6 hours after taking cholestyramine. If you are required to take one of the drugs or supplements listed below, your healthcare provider may need to adjust your dose or the time you take it, monitor you more closely for side effects, or discontinue your use of it all together:

• Thyroid hormones
• Lanoxin (digoxin)
• Birth control pills
• Cholesterol-lowering medications (including fibrates, ezetimibe, statins)
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Corticosteroids
• Diuretics (including hydrochlorothiazide, spironolactone, furosemide)
• Coumadin (warfarin)
• Fat-soluble vitamins (vitamins A, D, E, and K)
• Medication for seizures, such as Dilantin (phenytoin) and phenobarbital

There are several other medications that can also interact with cholestyramine, which is listed above. Therefore, you should make your healthcare provider aware of any prescribed and over-the-counter medications, and natural products that you are taking. This will help your healthcare provider to identify any potential interactions between cholestyramine and your other medications. 

Bottom Line

Cholestyramine is one of the first cholesterol-lowering medications approved in the United States. It is primarily used to lower your LDL cholesterol but has not been directly shown to produce death or complications from cardiovascular disease like some other lipid-lowering medications on the market. You should let your healthcare provider know if you are experiencing any problems with taking cholestyramine since the powdered form may have a gritty taste that may be a little hard to swallow for some people. Because cholestyramine only impacts your LDL cholesterol levels, your healthcare provider may decide to add other therapies—such as a statin or fibrate—to your lipid-lowering regimen.