McKenna's Pharmacology for Nursing, 2e

735

C H A P T E R 4 7 Lipid-lowering agents

■■ CAD is associated with arterial atheromas or plaques, narrowed arterial lumens and hardening of the artery wall, all of which lead to impaired contraction and vascular dilation. ■■ Risk factors for CAD include increasing age, male gender, genetic predisposition, high-fat diet, sedentary lifestyle, smoking, obesity, high stress levels, bacterial infections, diabetes, hypertension, gout and menopause. ■■ CAD prevention and treatment aim at decreasing risk factors to delay disease or decrease its progress. ■■ Hyperlipidaemia refers to an increase in the level of lipids (cholesterol and triglycerides) in the blood. ■■ Hyperlipidaemia increases a person’s risk for the development of CAD. ■■ Fats are taken into the body as dietary fats, then broken down in the stomach to fatty acids, lipids and cholesterol. ■■ Bile acids act like detergents to break down or metabolise fats into small molecules called micelles, which are absorbed into the intestinal wall and combined with proteins to become chylomicrons, to allow transport throughout the circulatory system. ■■ Cholesterol is a fat that is used to make bile acids; all cells can produce cholesterol, which is the base for steroid hormones and cell membrane structure. antihyperlipidaemic agent, which means that it works to decrease the levels of certain lipids, or fats, in your blood. An increase in serum lipid levels has been associated with the development of many blood vessel disorders, including coronary artery disease, which can lead to a heart attack. This drug must be used in conjunction with a low-calorie, low-saturated-fat diet and an exercise program. Evaluation Evaluate drug effects: lowering of serum cholesterol and lipid levels, prevention of first myocardial infarction, slowed progression of CAD. Monitor for adverse effects: sedation, dizziness, headache, cataracts, GI upset; hepatic or renal dysfunction; rhabdomyolysis. Monitor for drug–drug interactions as indicated for each drug. Evaluate the effectiveness of the teaching program. Evaluate the effectiveness of comfort and safety measures. TEACHING FOR M.M. • An HMG-CoA reductase inhibitor, or “statin”, is an

■■ The enzyme HMG-CoA reductase controls the final step that produces cellular cholesterol; HMG-CoA is active in every cell. LIPID-LOWERING AGENTS Lipid-lowering agents lower serum levels of cholesterol and various lipids. These include bile acid sequestrants, HMG-CoA reductase inhibitors and a cholesterol absorption inhibitor. Other drugs that are used to affect lipid levels do not fall into any of these classes but are approved for use in combination with changes in diet and exercise (see section on Other lipid-lowering agents). Box 47.5 summarises the use of lipid-lowering agents in different age groups. B ile acid sequestrants Bile acid sequestrants are used to decrease plasma cho- lesterol levels. Two bile acid sequestrants currently in use are cholestyramine ( Questran ) and colestipol ( Colestid). Therapeutic actions and indications Bile acid sequestrants bind with bile acids in the intes- tine to form an insoluble complex that is then excreted in the faeces (Figure 47.2). Bile acids contain high levels • Some of the following adverse effects may occur: • Headache, blurred vision, nervousness, insomnia : Avoid driving or performing hazardous or delicate tasks that require concentration; these effects may pass with time. • Nausea, vomiting, flatulence, constipation : Small, frequent meals may help. If constipation becomes a problem, consult with your healthcare provider for appropriate interventions. • Report any of the following to your healthcare provider: severe GI upset, vision changes, unusual bleeding, dark urine or light-coloured stools, or sudden muscle pain accompanied by fever. • You will need to have regular medical examinations to monitor the effectiveness of this drug on your lipid levels and to detect any adverse effects. These examinations will include blood tests and eye examinations. • Avoid grapefruit juice while you are taking this drug. • Tell any doctor, nurse or other healthcare provider that you are taking this drug. • Keep this drug, and all medications, out of the reach of children. • To help to decrease your risk of heart disease, follow these guidelines; adhere to a diet that is low in calories and saturated fat, exercise regularly, stop smoking and reduce stress.

KEY POINTS