Lecture 25+26 Flashcards
Type IIB Familial combined hyperlipidemia
high LDL and high VLDL
Overproduction of VLDL by liver
Type IV Familial hypertriglyceridemia
high VLDL
Overproduction and/or impaired catabolism of
VLDL
Type I Familial hyperchylomicronemia
increase in chylomicrons
deficiency in LPL or ApoCII
Type IIA Familial hypercholesterolemia
high LDL
Decreased or no functional LDL receptor
expression
Type III Familial dysbetalipoproteinemia
high IDL
Abnormal apoE
Type V Familial mixed hypertriglyceridemia
increase in chylomicrons and high VLDL
Increased production or decreased clearance of
VLDL & chylomicrons.
MOA of statins
Statins are competitive inhibitors of HMG-CoA reductase, the enzyme that catalyzes the first committed step of cholesterol biosynthesis
By inhibiting cholesterol synthesis statins
deplete intracellular supply of cholesterol
Depletion of intracellular cholesterol leads to
upregulation of HMG-CoA reductase, and upregulation
of the LDL receptor
Upregulation of LDL receptors results in increased clearance of LDL from the blood
The uses of statins
• Drugs of choice for LDL reduction.
• Reduce cardiovascular mortality.
• Lower LDL levels in all types of hyperlipidemias.
• Homozygotes for familial hypercholesterolemia
lack functional LDL receptors and thus benefit much less from treatment with statins.
• Contraindicated in pregnancy
AE of statins
Elevation of aminotransferases
Myopathy and rhabdomyolysis
Niacin
Decreases VLDL, LDL and Lp(a) levels.
It increases HDL levels
Most effective agent for increasing HDL and the only agent that may reduce Lp(a).
MOA of niacin
Niacin inhibits adenylyl cyclase in adipocytes. Leading to inhibition of hormone-sensitive lipase
In the liver niacin inhibits synthesis and
esterification of fatty acids. VLDL production is
decreased
increases LPL activity
uses of Niacin
• Niacin is the most effective drug for raising HDL.
• Particularly useful in patients with combined
hyperlipidemia and low HDL levels.
• Effective in combination with statins
AE of niacin
Intense cutaneous flush after each dose of niacin when the drug is started or the dose increased
taking aspirin before will decrease the flushing
Pruritus, rashes, dry skin. Acanthosis nigricans. Nausea and abdominal discomfort hepatotoxicity hyperglycemia elevate uric acid levels
Fibrates examples
Gemfibrozil
Fenofibrate
Fibrates lower VLDL levels and increase HDL
levels
MOA of fibrates
Fibrates activate peroxisome proliferator activated receptor-alpha (PPAR-alpha).
• PPAR-alpha receptors are expressed primarily in
liver and brown adipose tissue.
• Activation of PPAR-α by fibrates leads to a decrease in plasma TG levels and increase in plasma HDL levels due to the increase LPL and decreased expression of apoC-III
increase HDL and decrease TG
uses for the fibrates
DOC in severe hypertriglyceridemia
Reasonable consideration in moderate
hypertriglyceridemia.
As monotherapy, fibrates offer the highest TG reduction, followed by niacin, W-3-fatty acids, statins, and ezetimibe.
AE of fibrates
Mild GI disturbances.
Myositis
Lithiasis
drug interactions with fibrates
Gemfibrozil inhibits hepatic uptake of statins, thus more statin in blood
(Gemfibrozil competes for the glucuronosyl transferases that metabolize most statins)
increased risk for rhabdomyolysis
fenofibrate does not interfere with interact with statin metabolism
bile acid binding resins
Cholestyramine
Colestipol
Colesevelam
Useful only in hyperlipidemias involving isolated
increases in LDL