Antilipemic Drugs Overview

Antilipemic Drugs Overview

• Antilipemic drugs primarily reduce LDL cholesterol and total cholesterol levels.
• They can also increase HDL and decrease triglycerides in some patients.

HMG-CoA Reductase Inhibitors

• Commonly known as statins; all generic names end in "statin."
• Mechanism of action involves blocking HMG-CoA reductase, decreasing cholesterol synthesis and increasing LDL receptor numbers in the liver.

Side Effects and Risks

• The most significant side effect is myopathy; liver toxicity is also a concern.
• Regular liver function tests (AST/ALT) are recommended.
• All antilipemics may cause cataracts.

Therapeutic Uses

• Indicated for hyperlipidemia, primary and secondary prevention of cardiovascular events, post-myocardial infarction therapy, and protecting diabetics from myocardial infarction.

Contraindications

• Includes drug allergies, pregnancy (category X), and liver disease.

Adverse Effects

• Common issues include GI upset, headaches, rash, insomnia, and constipation.

Drug Interactions

• Increased risk of myopathy when used with other lipid-lowering drugs.
• Statin levels can be elevated by drugs that inhibit CYP3A3 and grapefruit juice.

Bile Acid Sequestrants

• Second-line agents used alongside statins; examples include colesevelam, cholestyramine, and colestipol.
• These agents interfere with bile acid reabsorption, necessitating greater cholesterol use for bile acid synthesis.

Contraindications and Adverse Effects of Bile Acid Sequestrants

• Contraindicated in individuals with biliary or bowel obstruction and phenylketonuria (PKU).
• Side effects are generally limited to the GI tract, including constipation, bloating, nausea, and indigestion.

Specific Bile Acid Sequestrants

• Colesevelam is the preferred choice available in powder form; taken with food.
• Cholestyramine, also a powder, can decrease vitamin K levels and affect bleeding when combined with anticoagulants like Coumadin.
• Colestipol is available in tablet form and should also be taken with food.

Niacin

• Primarily used to treat triglyceride levels in patients at risk for pancreatitis and to improve HDL levels.
• Side effects include flushing, gastrointestinal upset, liver toxicity, and hyperglycemia.

Preparations and Forms of Niacin

• Available in immediate release, timed-release, and extended-release formulations; over-the-counter doses typically do not cause adverse effects.

Fibric Acid Derivatives

• Considered as third-line drugs for lipid management, specifically effective in reducing triglycerides and raising HDLs.

Gemfibrozil and Fenofibrate

• Gemfibrozil is administered 600 mg twice daily, taken 30 minutes before meals; similarly, fenofibrate has analogous actions.
• Adverse effects can include gallstones, myopathy, and liver toxicity.
• Both drugs interact with warfarin and statins, increasing bleeding risk and myopathy, respectively.

Ezetimibe

• Works by inhibiting dietary cholesterol absorption; used as adjunct therapy with dietary modifications.
• Interacts with fibrates and bile acid sequestrants and is generally well tolerated; standard dosage is 10 mg per day.