Cholestyramine for Diarrhea

Cholestyramine is a medication primarily prescribed to lower cholesterol. However, because of its effects on bile acid, it sometimes is used as an off-label treatment for chronic diarrhea.

It belongs to a class of drugs known as bile acid binders or sequestrants and works by attaching itself to bile acids within the digestive tract so that they pass from the body. Cholestyramine is available as a generic drug and typically comes in a powder that can be added to beverages.

Uses

If you have high cholesterol, this reduction of bile acids from cholestyramine triggers your body to convert blood cholesterol into bile acids, which has the effect of reducing the levels of cholesterol in your blood. Cholestyramine is used along with dietary changes to lower LDL (low-density lipoproteins), or "bad" cholesterol, that raises risk of heart disease.

Cholestyramine is also prescribed to relieve pruritus (itchiness) associated with a partial bile obstruction and high levels of bile acids on the skin.

Off-Label Uses

If you have a condition known as bile acid diarrhea (BAD)—also known as bile acid malabsorption (BAM)—in which an excess of bile acids spill into the colon and trigger loose and watery stools, the medication has the effect of reducing diarrhea symptoms.

Bile acids are produced in the liver and stored in the gallbladder. They are released to aid in the absorption of fat and fat-soluble vitamin. After this digestive process, most unbound bile acids get reabsorbed and sent back to the liver to be recycled; only a small portion make its way through the intestines and colon. In people with BAD, a larger amount of bile acids get passed to the colon, where they increase motility and stimulate water secretion that result in diarrhea.

Cholestyramine may also be prescribed for Graves' disease, an autoimmune disorder that leads to an overproduction of thyroid hormones. Cholestyramine has been used for people with Graves' disease with severe thyrotoxicosis, which is high levels of thyroid hormones in the blood. The medication helps to bind thyroid hormones in the intestine, increasing their excretion so that blood levels of the thyroid hormones are reduced. 

Before Taking

Your doctor may do blood tests or collect stool samples to test for bile acids or may simply prescribe cholestyramine if BAM is suspected to see if it lessens or resolves your diarrhea. There are four different categories of BAM:

• Ileal diseases, including Crohn's disease, that prevents reabsorption of bile acids from the terminal ileum, which is the end of the small intestine that intersects with the colon
• Underlying diseases related to malabsorption, such as celiac disease, or diseases of the pancreas, such as chronic pancreatitis
• Diarrhea-predominant irritable bowel syndrome (IBS-D) with no clear underlying cause
• Excessive bile acid synthesis that can occur in those with hypertriglyceridemia, or high levels of fatty acids in the blood, or those on the diabetes drug metformin

Precautions and Contraindications

• Complete biliary obstruction: Don't take this drug if you have a full blockage of your bile ducts that doesn’t allow bile to be secreted into your intestine.
• Phenylketonuria (PKU): This drug contains the amino acid phenylalanine that can be dangerous for those with the inherited metabolism disorder PKU in which the body can't fully break down phenylalanine.
• Low vitamin K or folate: Chronic use of cholestyramine may stop your body from absorbing vitamin K, which can put you at risk of increased bleeding with injuries, and folate, a B vitamin that your body needs for a variety of processes, including maintaining red and white blood cells. Your doctor may have you take supplements of these vitamins if you're on cholestyramine.
• Hyperchloremic acidosis: This drug can lead to high levels of acids in the body, or a pH below 7.35, especially in children or petite patients who may get a higher relative dose. Acidosis can also occur in people with poor kidney function or those taking diuretics.
• Pregnancy or nursing: There are no adequate or well controlled studies of of how cholestyramine affects women who are pregnant or breastfeeding. However, because the drug is known to interfere with fat soluble vitamins, it may carry the risk of inadequate nutrition or affected milk production. For those taking this drug, prenatal vitamin dosage may need to be adjusted since it can interfere with the absorption of vitamins.
• Intestinal obstruction: Rare reports of intestinal obstruction in children have occurred and can be life-threatening.

Dosage

Cholestyramine comes in a powder or chewable bar when taken for cholesterol. A dose of 4 to 7 grams (g) of medication (often the equivalent of 5 to 9 g of powder) may be taken one to six times a day as instructed by a physician. The powder comes in a carton of individual packets or in a canister with a serving scoop.

When taken for pruritus associated with a partial bile obstruction, a dose of 4 g may given up to three times per day.

Cholestyramine for diarrhea is typically given as an initial dose of 4 g a day that may be increased as needed to 4 g taken two to four times per day.

For Graves' disease, 4 g may be given up to four times per day. As an alternative option, there may be a low dose of 1 to 2 g given as an adjunct therapy in combination with other medications.

Modification

A dose for children will vary based on body weight and symptoms but doesn't typically exceed 8 g per day split into two or three divided doses with amounts dependent on body weight.

How to Take and Store

• Always mix the powder form with 2 to 6 ounces of non-carbonated fluids, such as water, juice, or milk, before ingesting it. You can also put it in fluid-rich foods, such as pureed fruit or soup.
• Take this medication before a meal or prior to bed.
• Try to take other medications or vitamins at least 1 hour before or 4 hours after taking cholestyramine since it can interfere with their absorption.
• Store it at room temperature that's ideally between 66 and 77 degrees Fahrenheit
• If you use the bar form, be sure to drink plenty of water.
• Do not force or pack the powder into the serving scoop to make sure you aren't taking more than the prescribed dose.
• Drink the medication quickly instead of slowly sipping and brush your teeth often. If the medication is left in the mouth for prolonged periods, it can cause discoloration of teeth, erosion of enamel, or tooth decay.
• If you miss a dose, take it as soon as you remember; but if it's close to the next dose, skip it to avoid double dosing.

Side Effects

Side effects are more likely to occur in people over age 60. Check with your health care professional if any of the below side effects are persistent or bothersome or if you have any questions about them. Your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Common

The most commonly reported side effect of cholestyramine are digestive in nature and may ease as your body gets used to the medication.

• Constipation
• Abdominal discomfort or pain

The following side effects may also occur:

• Bloating
• Diarrhea
• Dizziness
• Gas
• Headache   
• Extra bleeding due to vitamin K deficiency
• Vitamin A or D deficiencies
• Osteoporosis
• Hyperchloremic acidosis, especially in children
• Rash or irritated skin or tongue

Severe

Seek medical help if you experience signs of an allergic reaction, such as hives, and call your doctor immediately if you experience:

• Rectal bleeding
• Severe abdominal pain
• Sudden loss of weight
• Vomiting
• Rectal bleeding or black stools

Warnings and Interactions

Tell your doctor if you are pregnant or breastfeeding or have any chronic health problems, such as diabetes, kidney disease, or heart or blood vessel disease.

Cholestyramine can delay or reduce the absorption of other oral medications, so be sure to tell your doctor what other medications you are currently taking, such as:

• Oral birth control pills or hormone therapy
• Penicillin G
• Phenobarbital
• Phenylbutazone
• Warfarin
• Thyroid drugs
• Oral phosphate supplements
• Thiazide diuretics
• Propranolol
• Tetracycline
• Digoxin