Pharmacology - Lipid-Lowering Drugs (Exam 4) Flashcards
T/F Lipids can be present in the blood without being bound to something
FALSE
How are lipids transported in the blood?
As protein-lipid complexes
What do protein-lipid complexes minimize?
Unfavorable hydrophobic-hydrophilic interactions
How are fatty acids transported in the blood?
Bound to albumin
Triglycerides derived from the diet are transported in what?
Lipoproteins
Large macromolecular complexed with proteins, triglycerides, and cholesterol
Lipoproteins
List the lipoproteins from biggest/least dense to smallest/most dense
- Chylomicrons
- VLDL
- IDL
- LDL
- HDL
- Free fatty acid-albumin complex
Largest, high % of triglycerides, lowest in density
Chylomicrons
2nd highest in triglycerides as a % of weight
VLDL
Highest in cholesterol esters as % weight
LDL
Highest in density due to high protein:lipid ratio
HDL
What are lipoproteins classified by?
Density
Fat ________
Protein ________
Cholesterol is ___________
Fat floats
Protein sinks
Cholesterol is in between
What is the essential component of cell membranes?
Cholesterol
What is the precursor of steroid hormones and bile acids?
Cholesterol
What does cholesterol play a role in?
Triglyceride transport
What is total cholesterol a combination of?
Cholesterol in VLDL, LDL, and HDL
What can shorten lifespan?
High blood cholesterol levels
What is the defining feature of atherosclerosis?
Deposition of cholesterol in arteries
What is the primary cause of premature death in the US?
Atherosclerosis
A type of fat that is carried in the blood and stored in fat cells throughout the body
Triglycerides
What are excess calories, sugar, and alcohol converted into?
Triglycerides
What is the building block of complex lipids?
Triglycerides
What can triglycerides be hydrolyzed to generate?
Fatty acids
What are the causes of high triglycerides in the general population?
Obesity
Inactivity
Smoking
Excess alcohol
High carb diets
Other disease (diabetes, renal failure)
Drugs (steroids, estrogen, etc)
Genetics
A triglyceride score of ______ or higher puts you at risk for metabolic syndrome
150
Metabolic syndrome is a clinical diagnosis that requires more than 3 of which risk factors?
Abdominal obesity
Elevated triglycerides
Reduced HDL cholesterol
Hypertension
Impaired fasting glucose
Atherosclerosis is caused from a development of what?
Fatty streaks and plaques in arteries
What happens when fatty streaks and plaques start developing in arteries? (ON EXAM)
Obstruct blood flow and weaken vessels
Macrophages invade injured endothelium -> become foam cells that die -> become part of plaque
T/F exogenous lipoprotein metabolism is from the diet
True
List the steps of exogenous lipoprotein metabolism
- Chylomicrons form in intestinal cells -> transport dietary cholesterol and triglycerides
- Enter circulation via intestinal lymph system
- Go to capillary endothelium of muscle and adipose tissue -> degraded to fatty acids, glycerol, monoglycerides by lipoprotein lipase
- Chylomicron remnants are depleted of triglycerides, but are enriched in cholesterol
- Chylomicron remnants enter liver -> bind to LDL receptor on hepatocytes -> taken up and metabolized to make more lipids
List the steps of endogenous lipoprotein metabolism
- VLDL synthesis in ER of hepatocytes
- VLDL secreted by liver into circulation
- Lipoprotein lipase degrades triglycerides to form IDL particles depleted of triglycerides
What are the 2 fates of IDL particles in endogenous lipoprotein metabolism?
- Bind to LDL receptor on hepatocytes -> get taken up and metabolized to make more lipids
- Metabolized by hepatic lipase on surface of hepatocytes -> form LDL -> LDL put into circulation -> taken up and metabolized by cells to make cholesterol
What is the suffix of lipid lowering drugs?
“-statin”
What is the class of lipid lowering drugs that we need to know?
HMG CoA reductase inhibitors (statins)
What are statins used for?
Hypercholesterolemia - caused by elevated LDL concentrations in people that have not responded to dietary modifications
What are statins ineffective in?
Familial hypercholesterolemia
Homozygous for defective LDL receptor gene
What is the mechanism of action of statins? (ON EXAM)
Competitively inhibit HMG CoA reductase, which is the rate-limiting step in endogenous cholesterol synthesis
Statins can decrease ___________ levels and increase _______________ levels
triglyceride; HDL cholesterol
Where are statins metabolized?
Liver
How are statins excreted?
Bile and feces
(some urinary elimination also)
What can statins cause?
Elevated liver enzymes
(liver function is often evaluated prior to tx)
What is used to make cortisol, estradiol, testosterone, aldosterone, vitamin D, etc?
Cholesterol
What are the adverse effects of statins?
Liver failure
Myopathy Rhabdomyolysis (skeletal muscle injury)
Who cannot use statins?
Pregnant women
What can statins increase the effects of?
Warfarin
Fibrates are derivates of _______ ________
fibric acid
What are fibrates used for?
Hypertriglyceridemias
What do fibrates lower?
Serium triglycerides
What do fibrates increase?
HDL
What is the possible mechanism of fibrates?
Activates ligands for PPAR-alpha, which is a transcription factor that regulates genes for lipid and glucose homeostasis
Which drug can increase incidence of Rhabdomyolysis if used in combination with statins?
Fibrates
What does nicotinic acid (niacin) increase and decrease?
Increase HDL and lipoprotein lipase
Decrease VLDL and LDL
What is the mechanism of nicotinic acid (niacin)?
Inhibit VLDL synthesis by stopping adipose tissue lypolysis and delivery of fatty acids to the liver
T/F nicotinic acid (niacin) has a long half life
FALSE, it has a very short half life
What does nicotinic acid (niacin) cause in 50% of people?
Flushing and GI distress
What can nicotinic acid (niacin) worsen in diabetic patients?
Insulin resistance
Hyperglycemia
Bile acid sequestrants are __________ in water
insoluble
Which drug is available as a dry resin that is mixed w/ juice and drank as a slurry?
Bile acid sequestrants
What do bile acid sequestrants decrease?
Decrease plasma cholesterol and LDL levels
What are bile acid sequestrants?
Anion exchange resins
What do bile acid sequestrants bind to?
Bile acids in the intestinal lumen
What are bile acids made from in the liver?
Cholesterol
What patients cannot take bile acid sequestrants?
Patients w/ homozygous familial hypercholesterolemia
(they do not have functional LDL receptors)
T/F bile acid sequestrants are absorbed
FALSE, they are NOT absorbed, so there are very few side-effects other than GI issues
What are some side effects of bile acid sequestrants?
- Binds to anionic drugs and decreases their absorption (ex: warfarin)
- Hyperchloremic acidosis
- Bad taste
What drug is a cholesterol absorption inhibitor?
Ezetimibe
What is the mechanism of Ezetimibe?
Blocks NPC1L1 to prevent lipid transport
Blocks cholesterol uptake in intesine
T/F Ezetimibe is effective at lowering lipid levels
FALSE, they are NOT very effective because they aren’t affecting endogenous lipid metabolism
T/F most cholesterol comes from the endogenous lipid pathway
True
Which patients cannot use Ezetimibe?
Patients with liver failure
T/F most patients are on a cocktail (combination) of lipid lowering drugs
True
What is the mechanism of omega-3 polyunsaturated fatty acids (fish oil)?
Decrease triglycerides
Inhibit synthesis of VLDL triglycerides and apolipoprotein B
Alter plasma cholesterol
Increase HDL
Which type of lipoprotein is the largest particle of low density, and who’s main function is to transport dietary lipids to tissues for use and storage?
A. LDLs
B. HDLs
C. Chylomicrons
D. IDLs
E. VLDLs
C. Chylomicrons
Which lipoprotein is considered a scavenger for cholesterol?
A. HDLs
B. LDLs
C. VLDLS
D. Chylomicrons
E. IDLs
B. LDLs
What is the function and location of lipoprotein lipase? (ON EXAM)
A. Transfer of cholesteryl esters from HDL to LDL and VLDL - Plasma
B. Hydrolysis of triglycerides in HDL and IDL - Liver
C. Esterification of free cholesterol to cholesteryl esters - Plasma
D. Hydrolysis of chylomicrons and VLDL triglycerides - Capillary Endothelium
E. Conversion of LDL into HDL – Intestinal epithelium
D. Hydrolysis of chylomicrons and VLDL triglycerides - Capillary Endothelium
What type of cells do macrophages become as they engulf more and more cholesterol, becoming large and vacuolated? (ON EXAM)
A. Plasma Cells.
B. Neutrophils.
C. Super macrophages.
D. Foam Cells.
E. Hepatocytes
D. Foam Cells.
How do the Bile Acid-Binding Resins (Cholestyramine, Colestipol, and Colesevelam) function?
A. By binding LDLs and removing them from circulation
B. By directly increasing HDL synthesis
C. By attacking the plaque directly
D. By binding bile acids
E. By inducing triglyceride metabolism
D. By binding bile acids
What type of individual would not benefit from the bile acid binding resins?
A. Hemophiliacs
B. Patients suffering from gout
C. Patients genetically deficient in functional LDL receptors
D. Patients with a fever
E. Patients in renal failure
C. Patients genetically deficient in functional LDL receptors
Which drugs are competitive inhibitors of hepatic HMG CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis? (ON EXAM)
A. Statins
B. Ezetimibe
C. Fibric acid derivatives
D. Bile acid-binding resins
E. Niacin
A. Statins
What drugs act as act as PPARalpha ligands ultimately resulting in increased lipases and therefore increased lipid degradation?
A. Statins
B. Ezetimibe
C. Fibric acid derivatives
D. Bile acid-binding resins
E. Niacin
C. Fibric acid derivatives
What drug class when used alone can have a side-effect of breakdown of muscle proteins that leads to renal toxicity with symptoms that include muscle pain and weakness and dark
urine?
A. Statins
B. Ezetimibe
C. docosahexaenoic acid
D. Bile acid-binding resins
E. Fibric acid derivatives
A. Statins
Which lipid lowering drug acts by inhibiting endogenous cholesterol synthesis?
A. Colesevelam
B. Ezetimibe
C. Fenofibrate
D. Fluvastatin
E. Niacin
D. Fluvastatin