Bile Acid Sequestrants: Lipid-Lowering Agents with a Twist

Bile acid sequestrants are positively charged molecules that attract the negatively charged bile acid molecules in the intestine, preventing them from getting absorbed. Moreover, the liver compensates by increasing the production of bile salts, eventually using up a lot of cholesterol. The liver also increases the uptake of low-density lipoproteins, hence lowering its levels in the blood.

Bile acid sequestrants are used as an additive in cholesterol-lowering therapy or when patient safety is a concern, such as in children and women.

Examples of bile acid sequestrants include:

• Cholestyramine
• Colesevelam
• Colestipol

Colesevelam and colestipol are available as tablets and resin powder, while cholestyramine is available as resin powder only.

Of note, bile acid sequestrants are not used as the first line of treatment for high cholesterol. However, they are used as an adjuvant medication in certain patient conditions.

Why Are Bile Acid Sequestrants Prescribed?

Too much LDL can lead to various life-threatening conditions, such as myocardial infarction, atherosclerosis, and deep vein thrombosis, by narrowing the arteries. Healthcare providers prescribe these agents to lower LDL levels.

Bile acid sequestrants are a drug of choice in conditions such as:

• Type IIa hyperlipoproteinemia (familial hypercholesterolemia)
• In a patient whose LDL levels do not lower despite dietary changes
• In a patient whose blood cholesterol report shows a severe risk of coronary artery disease
• Pruritus as these agents help lower the “pruritogens” that accumulate in cholestatic forms of liver disease
• In diabetic patients, to keep blood glucose levels controlled

How do Bile Acid Sequestrants Work?

Bile acid sequestrants are not absorbed through the gastrointestinal tract. However, they remain in the intestines for about five hours, where they combine with bile salts and are excreted through feces by forming an insoluble compound; hence, the levels of bile decrease. That forces the liver to synthesize bile from its precursor- cholesterol. Due to this, blood cholesterol levels decrease.

Since the small intestine needs bile acids to emulsify lipids and form chylomicrons, absorption of all lipids and lipid-soluble drugs decreases until the bile acids are replaced.

What are the Adverse Effects of Bile Acid Sequestrants?

Generally, bile acid sequestrants are well tolerated. However, in long-term use, they can cause adverse symptoms such as:

• Severe fecal impaction
• Vomiting
• Diarrhea
• Hemorrhoid irritation

Rarely, it can lead to:

• Peptic ulcers and bleeding
• Gallstones
• Inflammation of the gallbladder

Drug Interactions

Bile acid sequestrants are positively charged molecules. Therefore, they can hinder the absorption of other drugs. Here, we discuss the drug interactions that can occur with bile acid sequestrant therapy. They can:

Interfere with the absorption of digoxin, hydrocortisone, and oral phosphate supplements.

Decrease the absorption of drugs, such as propranolol, tetracycline, furosemide, penicillin G, hydrochlorothiazide, and gemfibrozil.

Interfere with the absorption of fat-soluble vitamins such as A, D, E, and K, as they need lipids to get absorbed. Vitamin K deficiency can affect the prothrombin time and increase the risk of bleeding. Therefore, monitor the prothrombin time with bile acid sequestrants.

What Nurses Should Keep In Mind With Bile Acid Sequestrants

As a nurse, evaluate if the patient should receive bile acid sequestrant therapy and for how long or which other drugs can be given. Here are the nursing processes appropriate for patients undergoing treatment with bile-sequestering agents.

Assessment

• Before therapy starts, check the patient’s blood cholesterol levels and any pruritus.
• Monitor the blood cholesterol and LDL levels periodically during the therapy.
• To monitor the drug’s effectiveness, check cholesterol and triglyceride levels every four weeks or ask the patient whether pruritus has diminished or abated.
• Monitor creatine kinase levels when the therapy begins and at six months. Also, check if the patient takes a cholesterol synthesis inhibitor and complains of muscle pain.
• Keep an eye on drug interactions and adverse drug reactions.
• Check the patient for fat-soluble vitamin deficiencies, including vitamins A, D, E, and K. Also, check the folic acid levels.
• Evaluate the patient’s and family member’s knowledge of drug therapy.

Implementation

• If bile acid sequestering drugs cause severe constipation, lower the dose, add a stool softener, or stop therapy.
• Give all other oral drugs one hour before or four to six hours after cholestyramine intake, as it can impair their absorption.
• For powder dosage forms, mix with 120 to 180 mL of liquid. Never administer dry powder alone because the patient may accidentally inhale and choke.
• To mix the powder, spread it on the preferred liquid or any other sauce, such as apple sauce, soup, or crushed pineapple. Let it stand for a few minutes, and then mix gently.
• If you mix the powder with carbonated beverages, remember that it will lead to excess foaming. Therefore, use a large glass and mix gently. Otherwise, it may spill.
• Tell the patient that after drinking the preparation, swirl a small additional amount of liquid in the same glass and then drink it to ensure ingestion of the entire dose.
• Ask the patient to take the bile acid sequestrants as prescribed and directed. Tell them not to take it in dry form as it can lead to esophageal irritation and severe constipation.

The Bottom Line

Bile acid sequestrants help lower LDL levels. With it, ask the patient to maintain a healthy lifestyle and make dietary changes with the medication. Patients should be instructed to maintain a healthy weight, cease smoking, and maintain a daily exercise routine.

As a nurse, you should counsel the patient about the adverse effects of bile acid sequestrants.

About the Author:

Mariya Rizwan is an experienced pharmacist who has been working as a medical writer for four years. Her passion lies in crafting articles on topics ranging from Pharmacology, General Medicine, Pathology to Pharmacognosy.

Mariya is an independent contributor to CEUfast’s Nursing Blog Program.

Please note that the views, thoughts, and opinions expressed in this blog post are solely of the independent contributor and do not necessarily represent those of CEUfast. This blog post is not medical advice. Always consult with your personal healthcare provider for any health-related questions or concerns.

If you want to learn more about CEUfast’s Nursing Blog Program or would like to submit a blog post for consideration, please visit https://ceufast.com/blog/submissions.