Antihyperlipidemics Flashcards
- What is the increased risk of cardiovascular mortality most closely linked to?
Elevated levels of LDL cholesterol and decreased levels of HDL cholesterol
**note that hyper-TAGs represents an INDEPENDENT risk factor
- What are the 6 categories of Fredrickson Classifications of Lipid disorders?
Type I → familial hyperchylomicroenmia [elevated chylomicrons due to LPL or apoCII def]
Type IIA → familial hypercholesterolemia [elevated LDL due to decreased LDL function] – DO NOT BENEFIT FROM STATIN TX due to defective LDL receptors
Type IIB → familial combined hyperlipidemia [elevated LDL and VLDL due to overproduction of VLDL by liver]
Type III → familial dysbetalipoproteinemia [elevated IDL due to abnormal apoE]
Type IV → familial hypertriglyceridemia [elevated VLDL due to impaired catabolism of VLDL]
Type V → familial mixed hypertriglyceridemia [elevated chylomicrons and VLDL due to increased production/decreased clearance of VLDL and chylomicrons]
**These are all primary hyperlipidemias most commonly seen in children, not adults (secondary hyperlipidemias are associated with adults)
- What is the most important secondary cause of hyperlipidemia in the developed world?
Sedentary lifestyle with excessive dietary intake of saturated fat, cholesterol and trans fatty acid.
- What are the common secondary causes of hypertriglyceridemia?
- diabetes mellitus
- chronic renal failure
- hypothyroidism
- alcohol excess
- contraceptives
- B-blockers
- Glucocorticoids
- What are the common secondary causes of hypercholesterolemia?
- hypothyroidism
- nephrotic syndrome
- obstructive liver disease
- glucocorticoids
- How are lipoprotein disorders measured?
Lipoprotein disorders are usually detected by measuring serum lipids after a 10 hr fast [TAGs are less than 400 mg/dL]
LDL=TC-[HDL+(TAG/5)]
- What is the first line drug to lower lipids?
Statins
- What are the 5 main classes of drugs used to treat hyperlipidemias?
- HMG-CoA reductase inhibitor [**most important]
- Niacin
- Bile acid-binding resins
- Fibric acid derivatives
- Cholesterol absorption inhibitors
- What are examples of HMG-CoA reductase inhibitors (Statins)?
- Atorvastatin – second most potent behind Rosuvastatin (2) [also lowers TAGs]
- Fluvastatin – least potent (5)
- Lovastatin – (4), prodrug
- Pravastatin – (4)
- Rosuvastatin – most potent in lowering LDL (1) [also lowers TAGs]
- Simvastatin – 3rd most potent (3), prodrug?
* *potency depends on ability to lower LDL
- What is the MOA of statins?
Statins are analogs of HMG that act as competitive inhibitors of HMG-CoA reductase – the 1st committed step of cholesterol biosynthesis. By inhibiting de novo cholesterol synthesis they decrease intracellular supply of cholesterol leading to an upregulation of HMG-CoA reductase and LDL receptors thereby clearing LDL from the blood.
- Who should NOT receive statins?
Women who are pregnant, lactating or likely to become pregnant
- What are the 4 categories of people who SHOULD be treated with statins?
- pts with clinical atherosclerotic CV disease
- pts with LDL greater than 190 mg/dL
- pts b/t age 40-75 with diabetes and LDL 70-189 mg/dL
- pts without atherosclerotic CV disease (ASCVD) or diabetes with LDL 70-189 mg/dL with estimated10 yr risk of ASCVD of 7.5% or greater
- Other than lowering LDL, what are the other beneficial effects of statins?
- improve endothelial function
- decrease platelet aggregation
- stabilize atherosclerotic plaque
- reduce inflammation
- What are the adverse effects of statins?
- Elevated aminotransferase – usually not associated with other liver toxicity
- Myopathy and rhabdomyolysis – rhabdomyolysis may cause myoglobinuria leading to renal injury
- What is the role of Niacin (nicotinic acid) in tx of hyperlipidemias?
Niacin inhibits adenylyl cyclase in adipocytes through Gi activation leading to inhibition of adipocyte hormone-sensitive lipase. By inhibiting this enzyme there is a reduced transport of fatty acids to the liver and decreases hepatic TG synthesis (inhibited synthesis and esterification of FAs). Therefore, Niacin leads to a decreased hepatic VLDL production and release, reduction of LDL, reduction of Lp(a), increase of HDL [decreased HDL catabolism].