Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
|
What are the steps in cholesterol synthesis?
|
Acetyl CoA--> HMG Co A---> Mevalonate---> Cholesterol---> LDL
HMG CoA---> Mevalonate with the use of HMG CoA reductase |
|
|
What are the HMG Co A reductase inhibitors?
|
Statins
Blocks Cholesterol Synthesis Statins are analogues of HMG Co-A that competitively inhibit catalytic site Statin has same structure as Acetyl Co A |
|
|
Effects of HMG CoA reductase
|
New cholesterol synthesis is blocked
Liver removes plasma LDL to release cholesterol for bile acid synthesis Hepatocyte LDL receptors upregulate Strategy is very effective with reduced cholesterol intake All cells can synthesize cholesterol |
|
|
What is Niacin or Nicotinic Acid?
|
Very effective to lower both cholesterol and TG’s, and raises HDL, too.
Action not related to vitamin effect Requires much higher doses Hepatic receptor recently identified Decreases hepatic fatty acid synthesis, so .. Reduces hepatic VLDL synthesis, and Increased hepatic LDL catabolism |
|
|
Niacin (Nicotinic Acid) Side Effects
|
Uncomfortable side effects:
flushing, pruritis fatigue, blurred vision Aspirin or ibuprofen relieves Tolerance develops Start lower and gradually increase dose Often given in combination with other anti-lipidemic drugs; it helps them all |
|
|
What are Bile Acid Binding Resins?
|
Natural substance, made from kelp
Taken orally, not digested, not absorbed Quaternary ammonium cationic exchange resin: Retards bile salt reabsorption so plasma LDL dissolved by liver to liberate cholesterol for more bile salts |
|
|
What are the cautions and side effects from Bile Acid Binding Resins?
|
Causes up-regulation of hepatic TGs and VLDL, and will aggravate primary hyper-TG-emias Cholestyramine, Colestipol, Colesevelam
GI discomfort, expensive, retards absorption of important lipid-soluble substances |
|
|
What are the lipid coluble drugs and vitamins in which are contra indicated with the use of Bile Acid Binding Resins?
|
Seriously reduce absorption of lipid-soluble drugs and vitamins:
acetominophen digitalis methotrexate thiazides anticoagulants thyroxine Vitamins A, D, E, K propranolol furosemide |
|
|
What's used to lower triglycerides?
|
Fibrates
|
|
|
How do Fibrates work?
|
Related to or converted to Fibric Acid
Increase activity of peripheral lipoprotein lipase, especially near adipose tissue. LL acts on VLDL to liberate FFA’s. Best for hypertriglyceridemias |
|
|
Are Fibrates useful for the hypercholesterolemias?
|
Remnants of VLDL are LDL and HDL, so fibrates are ineffective against usual hypercholesterolemias.
|
|
|
What is an additional effect of Fibrates?
|
Anti-inflammatory--similiar to the statins in that regard
|
|
|
What is Probucol?
|
Antioxidant; may reduce atherogenesis by preventing
LDL uptake into macrophages Blocks superoxide formation, thus .. Lorelco®, 0.5 g bid |
|
|
What condition may Probucol be helpful in?
|
May help in familial homozygous high cholesterol
|
|
|
What is Ezetimide?
|
Zetia
Blocks the transporter NPC1L1 Potentiates the mechanisms of Statins with questionable data |
|
|
What does HDL do?
|
HDL is involved in the redistribution of lipids from cells with excess cholesterol (e.g., macrophages) to cells requiring cholesterol, or to the liver for excretion.
|
|
|
What are Cholesterol Ester Transport Inhibitors?
|
The reverse cholesterol transport pathway directs excess cholesterol through HDL acceptors to the liver for elimination.
Inhibition of the transport protein (CETP) might elevate plasma HDL levels. |
|
|
Which medication class raises HDL?
|
CETP’s (Cholesterol Ester Transport Inhibitors) have a substantial effect to raise HDL-C, at expense of LDL-C
|
|
|
What are ACAT Inhibitors?
|
ACAT = Acyl-CoA:cholesterol acyltransferase
Potential rate-limiting step in synthesis and degradation of lipoproteins Catalyzes synthesis of cholesterol esters from free cholesterol fatty acid acyl-CoA ACAT-1 in skin cells and macrophages ACAT-2 in hepatocytes, intestinal lumen |
