Antilipemic Drugs: Cholesterol and Triglycerides

• Antilipemic drugs are used to treat high cholesterol and related conditions

Triglycerides and Cholesterol Fundamentals

• Lipids in the blood are water-insoluble and must bind to apolipoproteins
• Apolipoproteins are specialized lipid-carrying proteins
• The liver is a major organ for lipid metabolism, manufacturing cholesterol
• Lipoprotein is a combination of triglycerides or cholesterol and apolipoprotein
• Very-low-density lipoprotein (VLDL) is produced by the liver and transports endogenous lipids to cells
• Low-density lipoprotein (LDL) contributes to plaque formation in arteries
• High-density lipoprotein (HDL) is responsible for "recycling" cholesterol and is known as "good cholesterol"

Cholesterol and Coronary Heart Disease Risk

• Low HDL levels are defined as less than 40 mg/dL
• Total cholesterol levels of 300 mg/dL are three to four times greater than levels less than 200 mg/dL
• Higher cholesterol levels are associated with a higher incidence of death from coronary heart disease

Treatment Guidelines for High Cholesterol

• Antilipemic drugs are used to lower lipid levels and serve as an adjunct to diet therapy
• Drug choices are based on a patient's specific lipid profile
• Antilipemic drugs are recommended for clinical atherosclerotic cardiovascular disease
• Antilipemic drugs are recommended for LDL cholesterol at or above 190mg/dL
• Antilipemic drugs are recommended for diabetics ages 40-75 with LDL levels between 70-189mg/dL and no CVD evidence
• Antilipemic drugs are recommended for those without CVD or diabetes but LDL levels between 70-189mg/dL and high CVD risk factors within 10 years
• Non-drug methods like diet and exercise should be tried for at least six months before considering drug therapy

Types of Antilipemic Drugs

• HMG-CoA reductase inhibitors (HMGs or statins) inhibit cholesterol production
• Bile acid sequestrants help remove bile acids from the body
• Niacin (vitamin B3 or nicotinic acid) affects lipid metabolism
• Fibric acid derivatives (fibrates) are used to lower triglyceride levels
• Cholesterol absorption inhibitors (e.g., Zetia) reduce the absorption of cholesterol
• Herbal medications may also be used

HMG-CoA Reductase Inhibitors (Statins)

• Statins are among the most potent LDL reducers
• Examples of statins include pravastatin (Pravachol), simvastatin (Zocor), atorvastatin (Lipitor), fluvastatin (Lescol), rosuvastatin (Crestor), and pitavastatin (Livalo)
• Statins are administered orally, preferably with the evening meal
• Baseline cholesterol, HDL, LDL, triglyceride, renal, and liver function tests should be monitored before and periodically during statin therapy
• The effects of therapy are typically seen after 6-8 weeks

Action and Effects of Statins

• Statins function by inhibiting HMG-CoA reductase, reducing cholesterol production in the liver
• Statins lower the rate of cholesterol production
• Statins are a first-line therapy for hypercholesterolemia
• Outcomes of statin use include reduction of LDL levels, increase of HDL levels, and reduction of triglycerides
• Mild and transient GI disturbances
• Rash
• Headache
• Myopathy (muscle pain) that can lead to rhabdomyolysis,
• Elevated liver enzymes or liver disease
• Peripheral neuropathy

Statin Interactions

• Oral anticoagulants
• Drugs such as erythromycin, antifungals, verapamil, diltiazem and HIV protease inhibitors
• Amiodarone
• Grapefruit juice can delay the metabolism of statins

Bile Acid Sequestrants Details

• Used in conjunction with statins
• Examples are cholestyramine like Questran and colestipol hydrochloride known as Colestid
• Colesevelam (Welchol) is taken orally in tablet form with food and 8 ounces of water and not with other medications.

Action and Effects of Bile Acid Sequestrants

• Bile acid sequestrants prevent the reabsorption of bile acids from the small intestine
• Bile acids are needed for the absorption of cholesterol
• Side Effects that may get better overtime include Constipation, heartburn, nausea, belching, and bloating

Niacin (Nicotinic Acid) Action and Effects

• Niacin increases activity of lipase, which breaks down lipids, and decreases cholesterol and triglyceride metabolism
• Effects include flushing which is caused by histamine release, pruritus, GI distress, hyperglycemia, and hepatotoxicity

Fibric Acid Derivatives (Fibrates)

• Fibrates include gemfibrozil (Lopid) and fenofibrate (Tricor)
• Outcomes of fibrate use include decreased triglyceride levels and increased HDL levels

Action and Effects of Fibrates

• Fibrates activate lipase
• These suppress the release of free fatty acid from adipose tissue and inhibit synthesis of triglycerides in the liver
• Fibric Acid Derivatives can increase secretion of cholesterol in the bile
• The use of these drugs may have the following effects; abdominal discomfort, diarrhea, nausea, blurred vision and/or headache, increased risk of gallstones, prolonged prothrombin time, and myopathy

Interactions with Fibrates

• Oral anticoagulants
• Statins: increased risk for myositis, myalgias, rhabdomyolysis
• Fibrates can decrease hemoglobin and hematocrit levels as well as white blood cell count
• May lead to increased activated clotting time, lactate dehydrogenase levels, and bilirubin levels

Cholesterol Absorption Inhibitors

• Ezetimibe (Zetia) is a cholesterol absorption inhibitor often combined with a statin drug
• Recommended mainly when patients have not responded to other therapy
• The outcome is decreased total cholesterol, LDL, and triglyceride levels; increased HDL levels

Details on how to use Cholesterol Absorption Inhibitors

• Cholesterol absorption inhibitors inhibit the absorption of cholesterol secreted in the bile and from food
• Side effects include Hepatitis and Myopathy
• It is not for patients who have a mild to severe liver disorder

Herbal Products

• Some herbal products like Omega-3 is used to reduce cholesterol
• Can cause rash, belching and allergic reactions
• It can potentially interact with anticoagulant drugs

Further Information on Herbal Products

• Garlic: used as a lipid reducer; adverse effects include dermatitis, vomiting, diarrhea, flatulence, antiplatelet activity; possible interactions with warfarin and diazepam; may enhance bleeding when taken with NSAIDs
• Flax: both the seed and oil of the plant are used for hypercholesterolemia management; may cause diarrhea and allergic reactions; possible interactions with antidiabetic and anticoagulant drugs

Nursing Implications

• Contraindications include biliary obstruction, liver dysfunction, active liver disease
• Baseline liver function studies
• Patients on long-term therapy may need supplemental fat-soluble vitamins (A, D, K)
• GI upset can be decreased with meals
• Powder forms should be taken with a liquid but not dry
• Other medications should be taken 1 hour before or 4 to 6 hours after meals to avoid interference with absorption
• To minimize adverse effects of niacin, start on a low initial dose

Further Nursing Implications

• Small doses of aspirin or NSAIDs may be taken 30 minutes before dosing to minimize cutaneous flushing
• Several weeks are needed to show effectiveness
• Report persistent GI upset, constipation, abnormal/unusual bleeding, yellow discoloration of the skin
• Monitor for therapeutic effects (reduced cholesterol and triglyceride levels and adverse effects ( increased liver enzyme studies)

SDOH Information

• 30 Tablets of Zocor without insurance is $195.65
• 30 Tablets of generic lipitor is $126.99 without insurance
• 1 Box, 60 packet of generic cholestyramine is $148.99
• No insurance of a lipid panel can range from $200 to $843 but only $19 with private insurance or Medicare