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33 Cards in this Set
- Front
- Back
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What the prototype for organic nitrates?
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nitroglycerin
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What's the prototype for beta antagonists?
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propranolol
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What are the prototype for Ca-channel blockers? (3)
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nifedipine, verapamil, diltiazem
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What class of drugs is nitroglycerin?
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organic nitrates
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What class of drugs is nifedipine?
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Ca-channel blockers
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What class of drugs is verapamil?
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Ca-channel blockers
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What class of drugs is diltiazem?
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Ca-channel blockers
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Where does the pain felt in angina pectoris stem from?
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an inadequate metabolic supply for the working heart muscle (symptomatic of coronary insufficiency)
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What are the two forms of angina pectoris?
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(1) Exercise (Stress) -Induced Angina
(2) Resting (Variant, Prinzmetal's) Angina |
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What is exercise induced angina? What's the primary issue?
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This is the "classical" form, precipitated by exertion. The primary problem is one of atherosclerosis of the coronary vessels.
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What is variant angina? What's the primary issue?
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differs from "classical" angina because it typically occurs during rest, even nocturnally. The attack is precipitated by an intense spasm of a coronary vessel.
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Can the two types of angina co-exist in one patient
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Yup - they often do!
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What agents work to decrease O2 demand in the tx of angina? How?
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Beta blockers and some Ca blockers affect HR/contractility.
Organic nitrates and Ca blockers affect pre/afterload |
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What agents work to increase O2 supply in the tx of angina? How?
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Vasodilators (Ca blockers) increase coronary blood flow
Chronic statins/antithrombotics increase regional myocardial blood flow |
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What's the mechanism of action of organic nitrates?
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Increase NO which increases cGMP in smooth muscle cells, leading to the activation of myosine light chain kinase that dephosphorylates myosin causing relaxation
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What effect do organic nitrates have?
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Dilation of capacitance vessels leads to pooling of blood in veins = ↓ venous return ( ↓ preload).
Dilation of resistance vessels = ↓ PVR (↓afterload). |
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Route for organic nitrates?
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Sublingual (highly lipid soluable and rapid onset of action = 30 seconds)
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Metabolism of organic nitrates?
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Nitrate reductase in the liver
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Adverse effects of organic nitrates?
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headache
postural hypotension Nitrites = methemoglobinemia |
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Explain how tolerance and dependence occur with organic nitrates.
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some evidence of tolerance with repeated exposure.
Dependence seen when patients are subject to high concentrations at work (munitions factory workers) |
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Names of other nitrates? (4)
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Amyl nitrite
Isosorbide dinitrate Erythrityl tetranitrate Pentaerythritol tetranitrate |
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What the effect on HR and contractility with nitrates alone? What about in combination with beta or ca blockers?
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Alone = Reflex increase in both
Combo - decrease in HR and no change in contractility |
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With what physiologic measures do nitrates and beta/ca blockers have opposite effects which are cancelled out when these two drugs are given in combination?
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End-diastolic volume (dec w/ nitrates)
Contractility (reflex increase with nitrates) Ejection time (dec w/ nitrates) |
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What route of nitroglycerin has the shortest onset of action? Longest?
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Short = sublingual/buccal (1-3 min)
Long = oral/topical/transdermal (30-60 min) |
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What route of nitroglycerin has the shortest duration of action? Longest?
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30-60 min = sublingual
3-5 hrs = buccal/oral (if intact) 2-12 hrs = topical 18-24 hrs = transdermal |
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Route, onset and duration for amyl nitrite?
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Inhaled
Onset = 30sec Duration = 3-5 min |
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Route, onset and duration for erthrityl tetranitrate?
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Sublingual or chewable/oral
Onset = 5/30 min Duration = 3/6 hrs (respectively) |
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Route, onset and duration for Isosorbide dinitrite?
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Sublingual/oral/oral sustained
Onset = 2-5/20-40/60+ min Duration = 1-3/4-6/6-8 hrs (respectively) |
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Route, onset and duration for Isosorbide mononitrite?
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Oral
Onset = 30 min Duration = ? |
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Route, onset and duration for pentaerythritol tetranitrite?
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oral/oral sustained
Onset = 20-60/30 min Duration = 3-6/12 hrs (respectively) |
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When are beta blockers used in tx of angina?
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As prophylaxis when the pt's attacks are frequent and unpredictable
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What's the effect of beta blockers on the heart with regards to angina tx? Why?
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enhance exercise tolerance by reducing HR and contractile force (thus dec O2 demands). Also reduce BP which decreases “afterload”.
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What's the effect of ca channel blockers on the heart with regards to angina tx? Why?
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Tx “classical” angina by decreasing PVR (afterload).
Tx “variant” angina since they're extremely potent coronary vasodilators. |
