10 - Lipid Disorders Flashcards

1
Q

What are some primary disorders of lipoprotein metabolism?

A
  • Hypercholesterolemia (hyperC)
  • Hypertriglyceridemia (hyperT)
  • Mixed hyperC and hyperT
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2
Q

What are some secondary disorders that can cause problems w/ lipoprotein metabolism?

A
  • Diabetes
  • Hypothyroidism
  • Renal disease
  • Liver disease
  • Alcoholism
  • Some drugs
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3
Q

What is the normal level of cholesterol and LDL?

A
  • Cholesterol = less than 200

- LDL = less than 100

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4
Q

What is considered borderline high and high cholesterol?

A
  • Borderline = 200-239

- High = over 240

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5
Q

What is considered borderline high and high LDL?

A
  • Borderline = 130-159

- High = over 160

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6
Q

What is the consequence of hyperlipoproteinemia?

A

Atherosclerosis

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7
Q

What are the stages of atherosclerotic plaque formation?

A
  • Liver produces VLDL, which is converted to IDL, then LDL
  • LDL is oxidized and then taken up by macrophages
  • Forms foam cells and fatty streaks which accumulate and form fibrous plaques
  • Causes atheromatous ulcers and thrombosis
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8
Q

What is another name for LDL oxidation?

A

Lipid peroxidation

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9
Q

Will dietary cholesterol control work to prevent atherosclerosis in a px that doesn’t have hypercholesterolemia?

A

No, px must have hypercholesterolemia for dietary control to work

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10
Q

What is the function of bile acid sequestrants?

A

Bind bile in GI and disrupt enterohepatic circulation, decreasing and preventing reabsorption

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11
Q

Which drugs are bile acid sequestrants?

A
  • Cholestyramine
  • Cholestipol
  • Colesevelam
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12
Q

How do bile acid sequestrants lower LDL?

A
  • Reduce feedback inhibition of 7 alpha-hydroxylase by bile salts
  • More cholesterol is catabolized into bile acids, which are mostly excreted in feces
  • Expression of liver LDL receptors is increased so that liver can get more cholesterol from plasma LDL
  • Plasma LDL levels drop
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13
Q

What are statins? What do they result in?

A
  • HMG-CoA reductase inhibitors

- Lower cholesterol production, leading to lower plasma LDL levels

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14
Q

How are statins eliminated?

A

Biliary/fecal

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15
Q

Are statins reversible?

A

Yes

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16
Q

Can statins be given as a prodrug?

A

Yes, as a lactone (ester inside a ring system)

17
Q

What are the 2 main types of statins? Give examples of each

A

1) Natural statins (ex: lovastatin, simvastatin, pravastin)

2) Synthetic statins (ex: atorvastatin, fluvastatin)

18
Q

What are the 5 structural elements of an HMG-CoA reductase inhibitor?

A

1) Mevalonate equivalent (lactone or free acid)
2) Linker (either CH2-CH2) or (CH=CH)
3) Ring w/ hydrophobic substituents (decalin or heteroaryl)
4) Ester or 4-fluorophenyl
5) Methyl for decalins or isopropyl/cyclopropyl for heteroaryl

19
Q

What are some common adverse effects of statins?

A
  • Myalgia (muscle pain)
  • Myopathy (muscle weakness)
  • Rhabdomyolysis (muscle breakdown), rare
20
Q

What is monitored when a px is on statin drug therapy?

A

Hepatotoxicity is monitored by measuring alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in blood

21
Q

What do fibrates do?

A
  • Activate peroxisome proliferator-activated receptors (PPAR alpha)
  • Causing stimulation of fatty acid oxidation, inhibition of triglyceride synthesis, and reduced expression of ApoC-3 (inhibitor of lipoprotein lipase)
  • Results in more lipoprotein lipase available to remove triglycerides, lowering VLDL levels
22
Q

What do all fibrates have?

A

Isobutyric acid group attached to an oxygen which is then attached to a phenyl ring

23
Q

What is the active form of a fibrate?

A

Carboxylic acid

24
Q

Do fibrates have low or high log P values? What does this mean?

A
  • Relatively high (range from 3-5)

- Means they are highly lipid soluble, despite the presence of a carboxylic acid

25
Q

What are some adverse effects of fibrates?

A
  • Can result in increased cholesterol excretion via bile
  • May cause gall stones
  • Hepatotoxicity (myopathy, rhabdomyolysis)
26
Q

What does niacin do?

A
  • Inhibits lipoprotein lipase enzyme in adipose and muscle tissue to prevent lipolysis of triglycerides to free fatty acids => decreased production of VLDL => lower plasma levels of triglycerides and cholesterol
  • Also increased HDL
27
Q

What are the main side effects of niacin?

A
  • Flushing

- Px non-compliance

28
Q

What do ezetimibe do? Where is it located?

A

Located in small intestine where it inhibits absorption of cholesterol