C H A P T E R 4 7
Lipid-lowering agents
735
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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.
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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.
KEY POINTS
■■
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
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
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.
• 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.
