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USMLE - Pharm
Kaplan Section 3 Chapter 7 Anti-Hyperlipidemics
Question | Answer |
---|---|
What is 7-a-hydroxylase (CYP7A1)? | cholesterol ---(CYP7A1)---> bile acids (upregulated when cholesterol is high to reduce the level of cholesterol in hepatocytes, or when bile acids are low) |
Cholestyramine | Bile acid (BA) sequestrant. Complexes bile salts (BS)-->prevent recycling of BAs from GI-->dec BA levels in circulation-->dec inhib of CYP7A1-->inc synthesis of new BSs-->dec liver chol --> inc LDL receptors (to make more chol) --> dec LDL in plasma |
Colestipol | Bile acid (BA) sequestrant. Complexes bile salts (BS)-->prevent recycling of BAs from GI-->dec BA levels in circulation-->dec inhib of CYP7A1-->inc synthesis of new BSs-->dec liver chol --> inc LDL receptors (to make more chol) --> dec LDL in plasma |
When would you NOT use bile acid sequestrants? | in hypertriglyceridemias because they inc VLDL and TG's |
Adverse effects of bile acid sequestrants | 1. bloating, 2. constipation |
Drug interactions of bile acid sequestrants | Dec absorption of digoxin, thiazides, tetracyclines, warfarin, and vitamin K. |
What is HMG CoA Reductase? | Rate limiting enzyme in the synthesis of cholesterol |
What are statins? | Inhibit HMG-CoA Reductase --> decrease synthesis of cholesterol in liver --> inc LDL receptors --> dec LDL in circulation & dec hepatic synthesis of VLDL and ApoB |
What is the effect of statins on HDL and TG's? | small inc in HDL and small dec in TG's (atorvostatin) |
What is the effect of statins on vessels? | Inc in NO (vasodilator) and decreases mRNA for endothelin-1 (vasoconstrictor) |
Adverse effects of statins | 1. Diarrhea, 2. Myalgia/myopathy (watch CK), 3. rhabdomyolysis (gemfibrozil, nicotinic acid), 4. inc LFT's |
What is nicotinic acid? | anti-hyperlipidemic. 1. inhib VLDL and apoprotein synthesis in hepatocytes, 2. inc HDL --> dec plasma VLDL, LDL, and TG's, 3. activates lipoprotein lipases, 4. inc tPA, 5. dec serum fibrinogen |
Adverse effects of nicotinic acid | 1. flushing, 2. pruritis (use ASA), 3. rashes, 4. hyperuricemia, 5. hyperglycemia, 6. hepatotoxicity, 7. GI ulcer exacerbation. |
Gemfibrozil | anti-hyperlipidemic. 1. activates lipoprotein lipases --> inc catabolism of VLDL and LDL, 2. dec plasma VLDL, TG's, LDL, 3. small inc in HDL |
Adverse effects of gemfibrozil | 1. GI distress, 2. rash, 3. gallstones, 4. hypoK, 5. myositis |
Drug interactions of gemfibrozil | potentiates warfarin and sylfonylurea hypoglycemics |
Ezetimibe | anti-hyperlipidemic. 1. prevents intestinal absorption of cholesterol (used with statin to dec LDL) |
Adverse effects of ezetimbe | GI distress |