Block 2 - Dyslipidemia Med Chem Flashcards
Know how cholesterol is degraded?
Know the biosynthesis of TG?
What are the drugs within the bile acid sequestant class?
- Cholestyramine (Qestran, Prevalite)
- Colestipol (Colestid)
- Colesevelem (Welchol)
Describe the MOA of bile acid sequestants?
“Selectively” bind the negatively charged bile acids over other anions
What was Cholestyramine initially developed for?
Pruritus from increased bile acids
Describe the structure of Questran?
Polymer of styrene and cross linked with divinylbenzene
Describe the mechanism and treatment target of bile acid sequestrants?
Why is Questran poorly absorbed and not metabolized very well?
- Cholestryamine has decreased bioavailability in plasma
- Permanent charged amino decreases absorption
- Polymeric and very lipophilic structure
How does Colestipol different from Cholestryamine?
Colestid posses a more ionizable nitrogen → more bile acid binding per unit
Secondary/Tertiary amines ionized at intestinal pH
___ of tertiary amine leads to better binding of Colestid?
Methy iodide quaternization
Describe how Colesevelam fits the SAR of bile acid sequestrates?
- Polymeric
- 0% F
- Act in gut (localized)
- Changed amine
What are the ADRs of BA sequestants? How can it be avoided?
- Constipation: co-admin with dietary fibers or psyllium laxatives
- Worsen hypertriglyceridemia
- Should not be coadministered with other drugs (1 hr before or 4 hr after)
How does BAS induces TG synthesis?
Decreased BA → increased TG for decreased cholesterol → VLDL levels rise → Increase LDL receptors and return VLDL levels to pre-drug levels
A patient with pre-existing hypertriglyceridemia, leads to an increase in triglycerides
What is the MOA of HMGRI?
Inhibition of HMG-CoA reductase → Reducing biosynthesis of cholesterol → Compensatory increase of HMGCoA reductase and LDL receptors → Increased uptake of LDL → Cholesterol lowering
Treatment targets of HLD
How was Mevastatin discovered?
Consisted of Compactin that was a metabolite of Penicillium
Lovastatin (_____) is ___ more potent than Mevastatin
Mevacor; 2x
Describe the transition state of HMGCOa Reductase drugs
Describe HMGRI SAR?
- lactone ring was substituted to bicyclic ring other rings as long as it was lipophilic and contained ethylene bridges
- 7-substituted-3,5-dihydroxyheptanoic acids
Lovastatin Brand
Mevacor
Describe the metabolism of Mevacor?
Lovastatin undergoes lactone hydrolysis → Active from → Metabolized to more hydrophilic metabolites 6-OH or 3-OH
Increasing hydrophilicity doesn’t necessarily mean decreased activity
What HMGRI are prodrugs? Are they activated by esterase?
Lovastatin, Simvastatin
Lactone hydrolysis
How does Simvastatin differ from Lovastatin?
Additional methyl group
How does Pravastatin differ from Zocor and Metacor?
Pravachol has No lactone → Not a prodrug
17% F
Lovastatin/simvastatin = 5%
Pravastatin Brand
Pravachol
Natural
Simvastatin Brand
Zocor
Natural