736
P A R T 8
Drugs acting on the cardiovascular system
BOX 47.5
Drug therapy across the lifespan
Lipid-lowering agents
CHILDREN
Familial hypercholesterolaemia may be seen in children.
Because of the importance of lipids in the developing
nervous system, treatment is usually restricted to tight
dietary restrictions to limit fats and calories.
The HMG-CoA inhibitors simvastatin and atorvastatin
can be used in postmenarchal girls and boys 10 to
17 years of age for treating familial hypercholesterolaemia.
Pravastatin has been approved for use in children
older than 8 years of age, but these children should be
monitored very closely.
ADULTS
Lifestyle changes, including dietary restrictions, exercise,
smoking cessation and stress reduction, should be tried
before any antihyperlipidaemic drug is used.
HMG-CoA reductase inhibitors are the first drug of
choice in the treatment of hypercholesterolaemia in
people who are at risk for, or who have already developed,
coronary artery disease.The drugs are well tolerated and
less expensive than some of the other antihyperlipidaemic
drugs. Combination therapy with a bile acid sequestrant,
a fibrate, or nicotinic acid may be necessary if lipid levels
still cannot be reduced.
PREGNANCY AND BREASTFEEDING
Women of childbearing age should not take HMG-CoA
reductase inhibitors (Pregnancy Category X). Bile acid
sequestrants are the drug of choice for these women if a
lipid-lowering agent is needed.
OLDER ADULTS
No outcome data are available to prove the impact of lipid-
lowering agents in decreasing the incidence of myocardial
infarction or cardiac death in the older population.
Lifestyle changes, including dietary restrictions,
exercise, smoking cessation and stress reduction, should
be tried before any antihyperlipidaemic drug is used.
Lower doses of HMG-CoA reductase inhibitors should
be used in elderly people and in any person with renal
dysfunction. Care must be taken with those drugs that
cannot be cut, crushed or chewed. People should be
alerted about these restrictions.
Gemfibrozil,
fenofibrate,
clofibrate, nicotinic
acid work here
Ezetimibe
works here
HMG-
CoA
reductase
inhibitors
work
here
Bile acid
sequestrants
work here
Gemfibrozil, nicotinic acid
work here
-used as energy
-absorbed into circulation
-atheroma develops
-injured vessel
-inflame vessel
-becomes remnants
To heart—enter circulation
and reach periphery—stored
as fat
8
Liver processes fats
to LDLs, HDLs—enter
circulation and reach
periphery
9
Dietary fats
1
Stomach
2
Small intestine
3
Gallbladder contracts
and relases bile into
small intestine
4
Chylomicrons absorbed
into lymphatic system
7
Micelles absorbed into
small intestine wall,
packaged as chylomicrons
6b
Bile recycled to liver
5
Bile breaks fat into
micelles
6a
FIGURE 47.2
Sites of action of lipid-lowering agents.
