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26 Cards in this Set
- Front
- Back
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3 major disorders of heart diseases
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-Cardiac failure or contractile dysfunction
-Ischemic heart disease (angina, the primary symptom) -Cardiac arrhythmia |
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Goals of Drugs Used in Congestive Heart Failure
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-Removal of retained salt & H2O with diuretics
-Direct treatment of depressed heart with positive inotropic drugs such as digitalis gylcosides -Reduction of preload or afterload with vasodilators -Reduction of afterload & retained salt & H2O by angiotensin-converting enzyme inhibitors |
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characteristics of aglycone
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-Rings A-B & C-D are cis fused
-Ring B-C are trans fused -Resulting in characteristic “U-shape” |
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Positive Ionotropic Drugs
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-Cardiac Glycosides
-Beta agonists - PDE inhibitors |
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--------------are naturally occurring compounds present in digitalis (foxglove) plant,used for treatment of congestive heart failure (CHF)
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Cardiac Glycosides
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The two portions of Cardiac Glycosides
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-Sugar moiety
-Non-sugar moiety (the aglycone) |
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What is the major structural feature of cardiac glycosides at C-17?
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Lactone ring
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Bufadinolides
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6-membered lactone ring with 2 conjugated double bonds (α-pyrone) found from animals.
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Are 5-membered α,β-unsaturated lactones found from plants
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cardinolides
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Which one is different from the others and why?
A)Aglycone B)D-glucose C)D-digitoxose D)L-rhamnose E)D-cymarose |
Aglycone.All the others are sugar moieties of cardiac glycosides where as aglycone is a non-sugar moiety.
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---------- is the most frequently used cardiac glycoside.
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Digoxin
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How do you get Digitoxin & Digoxin (most important Cardiac glycosides)
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Partial hydrolysis of glucose molecule & acetate from LA and LC gives
Digitoxin & Digoxin, respectively |
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What important substances are obtained from Digitalis lanata (leaf)
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Dgitoxigenin :an aglycone
Lanoside A(a sugar) |
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What is the primary biochemical mechanism of action of cardiac glycosides ?
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Inhibition of Na+/K+-ATPase
-and therefore ↑ in contractile force |
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What is the structural requirement for the intrinsic activity of cardiac glycosides
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17-lactone
-is important for binding to active site |
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Lactone alone when not attached to steroid show no Na+/K+-ATPase inhibitory activity.What does this mean?
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– steroid ring must be important
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---------- refers to pressure-like pain caused by cardiac ischemia.
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Angina pectoris
-Antianginal drugs are used to prevent and alleviate |
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3 classes of drugs used as antianginal drugs
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-Nitrates (vasodilators)
-Calcium channel blockers(both vasodilator and cardiac depressant) -Beta blockers( cardiac depressant) |
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Which compound is commonly reffered to as Nitroglycerine,? Is it a nitro compound (NO2-C)?
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-Glyceryltrinitrate
-Not really a nitro compound (NO2-C) |
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What makes nitroglycerines and other organic nitrates very efficient in emergency anginal episodes?
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Lipophilic nature
- rapid absorption through biomembranes |
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How do organic nitrates act(MOA)?
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- Organic nitrates restore balance between O2 supply by
1. Venous dialation & 2. decreasing the myocardial load - are sources of nitric oxide (NO) in the body -Denitration of nitrates within smooth muscle cells release NO which stimulates guanylly cyclase, causing an increase in cyclic guanosine monophosphate (cGMP) -----> smooth muscle relaxation |
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Give examples of Calcium Channel Blockers
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-Diltiazem , verapamil (are both chiral)
-Nifedipine(dihydropyridine family) |
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These drugs block voltage-gated “L-type” Ca channel (most important in cardiac & smooth muscle)
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Calcium Channel Blockers
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Which enantiomer, dextro-rotatory (+) or levo-rotatory (-) is more potent as a Ca blocker (in Diltiazem & Verapamil )?
s a Ca blocker than the levo-rotatory (-) enantiomer one is more dextro-rotatory (+) dextro-rotatory (+) enantiomer is ~10X more potent as a Ca blocker than the levo-rotatory (-) enantiomer ~10X more potent as a Ca blocker than the levo-rotatory (-) enantiomer |
dextro-rotatory (+) enantiomer is ~10X more potent as a Ca blocker than the levo-rotatory (-) enantiomer.
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Class 1A Antiarrhythmic Drugs
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Na channel blockers
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A prototype drug acting on nerve & myocardiac membranes to slow conduction by blocking fast Na channels
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Quinidine
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