McKenna's Pharmacology for Nursing, 2e

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P A R T 8  Drugs acting on the cardiovascular system

Drug therapy across the lifespan

BOX 47.5

Lipid-lowering agents CHILDREN

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.

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

Gemfibrozil, nicotinic acid work here

Dietary fats 1

-used as energy -absorbed into circulation -atheroma develops To heart—enter circulation and reach periphery—stored as fat

8

HMG- CoA

reductase inhibitors

-injured vessel -inflame vessel -becomes remnants

work here

Stomach 2

Liver processes fats to LDLs, HDLs—enter circulation and reach periphery

9

Small intestine 3

Gallbladder contracts and relases bile into small intestine

4

Gemfibrozil, fenofibrate, clofibrate, nicotinic acid work here

Bile recycled to liver 5 Bile breaks fat into micelles 6a

Bile acid sequestrants work here

Ezetimibe works here

Micelles absorbed into small intestine wall, packaged as chylomicrons

6b

Chylomicrons absorbed into lymphatic system

7

FIGURE 47.2  Sites of action of lipid-lowering agents.