Bile acid sequestrants for lowering blood lipid levels:
This class of drugs works by blocking the absorption of bile acids or cholesterol from the intestines, causing them to be excreted in the feces and reducing the levels of free cholesterol in liver cells. They accelerate the breakdown and metabolism of low-density lipoprotein (LDL) cholesterol through the liver’s own regulatory mechanisms, thereby reducing cholesterol and LDL levels. They are only suitable for isolated hypercholesterolemia.
Due to the high cost and large dosage of these drugs, as well as the potential for foreign body and gastrointestinal reactions, they can easily cause constipation. Long-term use can interfere with the absorption of fat-soluble vitamins A, D, E, and K, making them less acceptable to patients. Therefore, they are rarely used nowadays.
(1) Cholestyramine (Bile acid sequestrants):
- [effect] it is used to treat primary hypercholesterolemia, and can also remove irritating cholic acid, so as to relieve skin itching caused by primary biliary cirrhosis and biliary obstruction. It can reduce low-density lipoprotein and cholesterol.
- [usage and dosage] 1~6 times a day, 4~5g each time, the total amount is no more than 24 times a day.
- [adverse reactions] common adverse reactions include vomiting, nausea, gastrointestinal bleeding. Large doses can cause steatorrhea and osteoporosis. It can also have bad taste and constipation. Constipation can be alleviated by eating more fiber. Those with bad taste can be corrected with seasoning. Rare adverse reactions include lipodysentery, diarrhea, severe abdominal pain and intestinal obstruction.
- [precautions] for those who take colexemide for a long time, vitamin A, vitamin D, vitamin K, calcium and folic acid can be appropriately supplemented. Especially pregnant and lactating women. Because colexemide will interfere with the absorption of digoxin, warfarin, probucol, fibrates and statins, it should be taken 1-4 hours before taking colexemide or 4 hours after taking colexemide.
(2) Colestipol (Bile acid sequestrants):
- [Action] This drug can reduce serum cholesterol and LDL-C levels, promote regression or slow the progression of atherosclerotic plaques, but has no significant effect on triglycerides.
- [Dosage] Take 1 to 2 times daily, 10 to 20 grams each time, mix with water or beverage before consumption to reduce esophageal irritation. It is generally recommended to take before meals or at bedtime.
- [Adverse Reactions] Adverse reactions include nausea, vomiting, constipation, dizziness, abdominal discomfort, and allergic reactions.
- [Precautions] Since this drug affects the absorption of cefaclor, thiazide diuretics, lincomycin, phenobarbital, and warfarin, it should be taken 1 hour before or 4 hours after taking the medication to ensure good absorption.
(3) Probucol (Bile acid sequestrants):
- [Action] This drug can lower cholesterol and LDL-C levels, which is beneficial for the prevention and treatment of atherosclerosis. It can also lead to regression of Achilles tendon xanthomas and skin xanthomas in patients.
- [Dosage] Take twice daily, 0.2 to 0.5 grams each time. Take with breakfast and dinner.
- [Adverse Reactions] Common adverse reactions include abdominal pain, diarrhea, and nausea. Rare adverse reactions include elevated levels of serum transaminases, alkaline phosphatase, creatine kinase, as well as transient increases in bilirubin, uric acid, blood urea nitrogen, and blood glucose.
- [Precautions] Prolonged use of this drug can cause prolongation of the Q-T interval on the electrocardiogram (EKG), so it should be avoided in patients with low blood potassium, arrhythmias, and prolonged Q-T interval.