Niño Adonis Melgar April 27, 2009BSN-2

WRITTEN REPORT ON ANTILIPIDEMIC AND VASODILATOR

DRUGS

I. ANTILIPIDEMIC Drugs

A. DefinitionAntilipidemic or Antilipemic or Hypolipidemic agents are used to lower

abnormally high blood levels of lipids (fatty substances). In normal amounts, lipids help produce energy, maintain body temperature, and provide the chemical precursors of certain body constituents. In abnormally high amounts, lipids allow excess cholesterol to form and deposit in the blood vessels as atherosclerotic plaques. These plaques contribute to hypertension, slow flow of oxygenated blood to the heart and other body organs, and increase the risk of coronary artery disease (CAD), which kills more than 500,000 people in the USA each year.

Lipids are composed of free fatty acids (FFAs), triglycerides (glycerol esters of FFAs), sterols (cholesterol and cholesterol esters), and phospholipids (phosphoric acid esters of lipid substances).

B. Lipoprotein Groups

1. chylomicrons2. very low density lipoproteins (VLDL)3. low density lipoproteins (LDL)4. high density lipoproteins (HDL) – only friendly or good lipoprotein

and its main function is to remove cholesterol from blood stream and deliver it to the liver

C. Nonpharmacologic Methods of Cholesterol Reduction

1. reduction of saturated fats and cholesterol in the diet2. exercise3. say no to smoking

D. Types of Antilipidemics

1. Bile acid Sequestrants cholesteramin resin colesevelem

cholestipol HCl

۞PharmacokineticsThese drugs are not absorbed in the GI tract because of higher

molecular weight. Instead, they remain in the GI tract where they combine with bile acids for 5 hours. Eventually, it is excreted in the feces.۞Pharmacodynamics

These lowers the blood levels of LDL. Since it combines with the bile acids in the GI tract, the level of bile acids in the liver will decrease. This triggers the liver to synthesize more bile acids from cholesterol. And as cholesterol leaves the blood and other areas, the blood cholesterol level decreases.

2. Fibrates (Fibric Acid) clofibrate fenofibrate gemfibrozil

۞ PharmacokineticsThese drugs are absorbed readily in the GI tract. After absorption,

95% of the latter is found in plasma proteins. Then they will be metabolized in the liver to form metabolites and then excreted via urine and as conjugates of glucoronic acids.۞Pharmacodynamics

These increases HDL levels in the blood by increasing the synthesis of apoprotiens (substances derived from proteins), and it increases the serum’s capacity to dissolve additional cholesterol.

3. Nicotinic Acid nicotinic acid antihyperlipidemic ezetimibe

۞ PharmacokineticsThese can be absorbed readily and distributes throughout the body.

Some doses are excreted unchanged in urine.۞Pharmacodynamics

Inhibits the release of FFA’s from lipid tissues.

4. Statins atorvastatin calcium fluvastatin sodium tovastatin pravastatin sodium simvastatin rosuvastatin calcium

۞ PharmacokineticsThese are absorbed from the GI tract, highly protein bound,

metabolized in the liver, and excreted in the urine and feces.۞Pharmacodynamics

These drugs are responsible for the conversion of hepatic 3-hydroxy 3-methylglutaryl reductase inhibitor into mevalonate. This action inhibits the cholesterol synthesis since mevalonate is a precursor of cholesterol and other sterols.

II. VASODILATORS

A. DefinitionVasodilators increase the blood flow to the extremities. It also decrease the

systolic and the diastolic BP by relaxing arteriolar smooth muscle, leading tpo arteriolar dilation and decrease peripheral resistance.

B. 2 Main AgentsDirect Vasodilator – acts on arteries, veins, or both

diazoxide hydralazine HCL minoxidile sodium nitroprusside

Calcium Channel Blockers – preventing the entry of CA2+ into the cells thus reducing the activity of vascular smooth muscles amlodipine besylate felodipine isradipine diltiazem HCl nicardipine HCl nifedipine verapamil HCl

۞ PharmacokineticsThese drugs are absorbed rapidly and distributed well. They are all

metabolized in the liver and most are excreted in the kidneys.۞Pharmacodynamics

Direct vasodilators relax peripheral vascular smooth muscles, lowering BP by ioncreasing the blood vessel caliber and reducing total peripheral resistance. Calcium channel blockers prevent calcium transport across the cell membrane, reducing the activity of the vascular smooth muscle, thus producing vasodilation and lowering the BP.

Reference:Clinical Pharmacology and Nursing, 3rd edition, Baer and Williams, 1996