antilipemic drug -pharmacology ppt
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ANTILIPEMIC DRUGS(ANTIHYPERLIPIDEMIC AGENTS)
By: MJJH
ANTILIPEMIC DRUGS(ANTIHYPERLIPIDEMIC AGENTS)
Used for patients/clients with elevated blood lipids, such as cholesterol, triglycerides, and phospholipids.
Drugs are used in combination with lifestyle changes (such as proper diet, weight loss, and exercise) to decrease
the risk of CAD.
THE CLASSES OF ANTILIPEMIC DRUGS
INCLUDE:
BILE-SEQUESTERING DRUGS- The bile-sequestering drugs are cholestyramine, colestipol, and
colesevelam.
Bile Sequestering drug bind with bile acids, leading to their
excretion in the feces.
Pharmacokinetics-Bile-sequestering drugs aren’t
absorbed from the GI tract. Instead, they remain in the
intestine, where they combine with bile acids for about 5 hours.
Eventually, they’re excreted in stool.
Pharmacodynamics-The bile-sequestering drugs lower blood levels of low-density lipoproteins
(LDLs). These drugs combine with bile acids in the intestines to form an insoluble compound
that’s then excreted in stool. The decreasing level of bile acid in
the gallbladder triggers the liver to synthesize more bile acids.
Pharmacotherapeutics- Bile-sequestering drugs are the drugs
of choice for treating type ii hyperlipoproteinemia (familial
hypercholesterolemia) when the patient can’t lower his LDL levels
through diet alone.
Drug interactions- They may bind with acidic drugs in the GI
tract, decreasing their absorption and effectiveness. Bile-
sequestering drugs may reduce absorption of lipid-soluble
vitamins, such as vitamins A, D, E and K. Poor absorption of vitamin K can affect prothrombin times
significantly, increasing the risk of bleeding.
ADVERSE REACTIONS TO BILE-SEQUESTERING DRUGS
Short-term adverse reactions to these drugs are relatively mild.
More severe reactions can result from long-term use. Adverse GI effects with long-term therapy include severe fecal impaction,
vomiting, diarrhea, and hemorrhoid irritation.
FIBRIC ACID DERIVATIVES
Fibric acid is produced by several fungi. Two derivatives of this acid are Fenofibrate and gemfibrozil.
These drugs are used to reduce high triglyceride levels, and to a lesser extent, high LDL levels.
Pharmacokinetics- Fenofibrate and gemfibrozil are
absorbed readily from the GI tract and are highly protein-
bound. Fenofibrate is hydrolyzed while gemfibrozil
undergoes extensive metabolism in the liver. Both
drugs are excreted in the urine.
Pharmacodynamics- Although the exact mechanism of action for these
drugs isn’t known, researchers believe that fibric acid derivatives may:
•Reduce cholesterol production early in its formation
•Mobilize cholesterol from the tissues•Increase cholesterol excretion
•Decrease synthesis and secretion of lipoproteins
•Decrease synthesis of triglycerides.
Pharmacotherapeutics- Fibric acid drugs are used primarily to
reduce triglyceride levels, especially very-low-density
triglycerides, and secondarily to reduce blood cholesterol levels. They’re typically used to treat
patients with types ii, iii, iv, and mild type v hyperlipoproteinemia.
Drug interactions- Fibric acid drugs may displace acidic drugs, such as barbiturates, phenytoin, thyroid derivatives, and cardiac glycosides. The risk of bleeding
increases when fibric acid derivatives are taken with oral
anticoagulants.
HMG-COA REDUCTASE (OR 3-HYDROXY-3-METHYL-GLUTARYL-
COA REDUCTASE OR HMGCR)is the rate-controlling enzyme of the mevalonate pathway, the metabolic
pathway that produces cholesterol and other
isoprenoids.If these enzyme is blocked, serum
cholesterol and LDL levels decrease, because more LDLs are absorbed by
the cells for processing into cholesterol. HDL levels increase slightly with this alteration in fat
metabolism.
Therapeutic Action and Indications- HMG-coA Reductase inhibitors block the formation of cellular cholesterol, leading to
decrease in serum LDLs, with a slight increase or no change in the levels of HDLs. Because these drugs undergo a
marked first-pass effect in the liver, most of their effects on the process that generates atheromas in vessel
walls. That exact mechanism of action is not understood.
These drugs are indicated as adjuncts with diet and exercise for the treatment of increased cholesterol and LDL levels that
are unresponsive to dietary restrictions alone; to slow the progression of CAD in patients with documented CAD; and to prevent first MI in patient who
are at risk for MI.
Pharmacokinetics-the statins are all absorbed from the GI tract
and undergo the first- pass metabolism in the liver. They are excreted in the feces and urine. The peak effect of this drug is usually seen within 2-4 weeks. These drugs cross the placenta and have been associated with skeletal malformations of he
fetus.
Contraindications and action- These drugs are contraindicated in the presence of allergy to any
of the statins or to fungal byproducts or compounds. They
are also contraindicated with active liver disease or a history of alcoholic liver disease, w/c could exacerbate, leading to
severe liver failure.
Adverse Effect- The most common adverse effects
associated with these drugs reflect their effects on the GI system: flatulence, abdominal pain, nausea, vomiting, and
constipation. CNS effects can include headache, dizziness, blurred vision, fatigue, and
cataract development and may effect changes in the cell
membrane and synthesis of cholesterol.
Cholesterol Absorption Inhibitors- are a class of
compounds that prevents the uptake of cholesterol from the small
intestine into the circulatory system.
Lower the amount of cholesterol that your body absorbs. So your blood has lower total cholesterol and lower LDL (bad) cholesterol
Therapeutic action and indications- Ezetimibe works in the brush border of the small intestine
to decrease the absorption of dietary cholesterol, leading to drop in serum cholesterol levels. It is indicated as an adjunct to diet and exercise to
lower cholesterol levels as monotherapy or as part of
combination therapy with an HMG-CoA inhibitors or a bile acid
sequesterant.
Pharmacokinetics- Ezetimibe is absorbed well after oral
administration, reaching peak levels in 4-6 hours. It is
metabolized in the liver and the small intestine, with a 22 hours half- life. Excretion in the feces
and urine.
Contraindications and Cautions- Ezetimibe is
contraindicated with allergy to any component of the drug. If it
is used in combination with a statin, it should not be used
during pregnancy or lactation or with severe liver disease
because of the known effects of statins, including possible liver
problems and renal failure.
Adverse Effect- The most common adverse effect associated with
ezetimibe are mild abdominal pain and diarrhea. It is not associated with the bloating and flatulence
that occurs with the bile acid sequestrants and fibrates, other
adverse effect have been reported include headache, dizziness,
fatigue, URI, back pain, muscle aches and pain.
NICOTINIC ACID- Lowers total cholesterol, LDL-cholesterol, and triglyceride levels, while raising
HDL-cholesterol levels.Vitamin B (Niacin) or Nicotinic Acid, inhibits release of free fatty acids in
the adipose tissue, increases the rate of triglyceride removal form
plasma, and generally reduces LDL and triglycerides level and increases
HDL levels.
The initial effect on lipid levels is usually seen within 5 to 7 days,
with the maximum effect occurring 3 to 5 weeks. Niacin is
associated with intense cutaneous flushing, nausea, and abdominal pain, making its use
somewhat limited.
It also increases serum levels of uric acid and may predispose patients to the development of gout. Niacin is often combined with bile acid sequestrants fro increased effect. It is given at
bedtime to make maximum use of nighttime cholesterol synthesis, and it must be given 4 to 6 hours after bile sequestrant to ensure
absorption.