Lipid lowering Drugs. Flashcards
List in order of size the classes of Lipoproteins.
From largest to smallest.
Chylomicrons,
VLDL,
LDL,
HDL.
Where are chlomicrons synthesized and what does this indicate about the origin of the triglycerides it carries?
Intestine, dietary origin.
By which organ is VLDL secreted?
The liver.
What is the function of VLDL?
Transport of triglycerides from the liver to peripheral tissues.
List the important enzymes in Cholesterol Metabolism.
LPL - Lipoprotein Lipase,
HMG CoA reductase,
LDL receptors,
LCAT - lecithin cholesterol acyl transferase,
CETP - Cholesteryl ester transfer protein.
What is the function of Lipoprotein Lipase?
It clears chylomicrons from the ciirculation and breaks down Triglycerides to FFA and glycerol producing IDL and LDL.
Where is Lipoprotein lipase found?
Mainly in the blood.
HMG CoA reductase.
Involved in the rate limiting step of cholesterol synthesis where HMG is converted to Mevalonate.
How do LDL receptors come in to the picture of lowering levels of lipids in blood?
LDL receptors on tissue bind with LDL and internalizes it. The receptor then returns to the membrane.
What is Hyperlipidemia?
Elevation of cholesterol, triglycerides or both.
Describe the condition of familial hypercholesterimia.
An autosomal dominant trait with defects in LDL receptors. It is characterized by high levels of serum cholesterol and LDL.
Name a few causes of Hyperlipidemia.
Familial,
Polygenic lipid disorders (Diet, physical activity),
Secondary to other disease (Diabetes mellitus, alcoholism, nephrosis, drugs taken for other diseases).
What is meant by the term pleitrophic.
They can be described as complementary effects that are not adverse.
Explain the underlying principle behind lipid lowering treatment.
First the patients’ current health status will be avaluated and depending on this a management plan will be made. If Diet and life style cannot be managed well, then drug treatment will be prescribed.
Name the classes for hypolipidemic drugs (drugs that will lower lipid levels).
Statins, Fibrates, Cholesterol absorption inhibitors, Niacin, Fish oil derivatives.
Explain how statins work?
Analogues of HMG Co A and so competitively inhibit HMG Co A enzyme.
Promotes expression of LDL receptors in the liver.
What effect would increased expression of LDL receptors in the liver have?
Increased clearance of LDL.
Other indications for statins?
Given for patients with high risk CHD and to prevent MI and stroke.
List some Pleitrophic effects of statins (other than lowering LDL)?
Improved endothelial function, Decreased oxidative stress, Plaque stabilisation, Antithombotic, Enhanced fibrinolysis, Immune supression.
Name two statins which are prodrugs.
Simvastatin and Lovastatin.
What should you advice a patient receiving statins which are prodrugs?
Stay away from grape juice. It can inhibit activity of Cytochrome P450 needed for the activation of the prodrug.
Contraindications of statins.
Pregnancy as it is teratogenic,
Use with caution with people with liver dysfunction.
How do fibrates work?
They bind to nuclear receptors and control (upregulate) LPL which would promote breakdown of triglycerides.
List the side effects of Fibrates.
GI disturbance, Fatigue, Rashes, Muscle cramps, Gall stones.
