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Katzung - Chapter 12
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Katzung - Chapter 12

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Questions and Answers

What is a key reason amyl nitrite is considered obsolete for treating angina?

  • It has a long duration of action.
  • It has an unpleasant odor and a short duration of action. (correct)
  • It can only be administered intravenously.
  • It is ineffective in releasing vapors.

    • Which mechanism is primarily responsible for nitroglycerin's therapeutic effects?

  • It selectively constricts veins to improve blood flow.
  • It releases adrenaline to increase heart rate.
  • It opens calcium channels in vascular smooth muscle.
  • It causes vasodilation through nitric oxide release. (correct)

    • Which metabolite of nitroglycerin is believed to provide most of its therapeutic effect?

  • 5-mononitrate metabolite
  • 1-mononitrate derivative
  • 1,2-dinitro derivative (correct)
  • Isosorbide mononitrate

    • How does nitroglycerin primarily affect the vascular smooth muscle?

    <p>It relaxes all types of smooth muscle regardless of tone.</p> Signup and view all the answers

    What is the primary route of excretion for nitroglycerin's metabolites?

    <p>Primarily via the kidney</p> Signup and view all the answers

    What is the bioavailability of isosorbide mononitrate?

    <p>100%</p> Signup and view all the answers

    What effect does nitroglycerin have on atheromas?

    <p>It prevents significant dilation in concentric lesions.</p> Signup and view all the answers

    What is the half-life of unchanged nitrate compounds after administration?

    <p>2–8 minutes</p> Signup and view all the answers

    Which of the following is true about the absorption of nitroglycerin?

    <p>It avoids the hepatic first-pass effect.</p> Signup and view all the answers

    What is the primary purpose of ranolazine in medical treatment?

    <p>Approved for use in angina</p> Signup and view all the answers

    Why are immediate-release short-acting calcium channel blockers contraindicated in patients with unstable angina?

    <p>They increase the risk of adverse cardiac events</p> Signup and view all the answers

    What beneficial effect do β-blocking drugs have in managing effort angina?

    <p>Decrease heart rate and blood pressure</p> Signup and view all the answers

    Which metabolic modulator is mentioned as a known pFOX inhibitor?

    <p>Trimetazidine</p> Signup and view all the answers

    What cardioprotective effect is associated with a lower heart rate due to β-blocking agents?

    <p>Increased coronary perfusion time</p> Signup and view all the answers

    Which drug can decrease the frequency of postinfarction angina in patients with non–Q-wave myocardial infarction?

    <p>Diltiazem</p> Signup and view all the answers

    What does nitric oxide primarily activate in the body?

    <p>Soluble guanylyl cyclase</p> Signup and view all the answers

    What physiological effect does the formation of cGMP primarily lead to?

    <p>Smooth muscle relaxation</p> Signup and view all the answers

    What compensatory response can result from decreased arterial pressure?

    <p>Tachycardia</p> Signup and view all the answers

    Which condition is commonly associated with a lack of increased coronary blood flow during nitroglycerin therapy?

    <p>Atherosclerotic obstructive coronary artery disease</p> Signup and view all the answers

    What mechanism contributes to the development of nitrate tolerance?

    <p>Decrease in sulfhydryl groups</p> Signup and view all the answers

    What effect does nitroglycerin have on the heart?

    <p>It exerts a weak negative inotropic effect.</p> Signup and view all the answers

    What is a significant physiological effect noted during nitrate therapy?

    <p>Diminished availability of CGRP</p> Signup and view all the answers

    During nitrate therapy, which substance is important in smooth muscle relaxation aside from cGMP?

    <p>Prostaglandin E</p> Signup and view all the answers

    Which organ systems have demonstrated relaxation of smooth muscle during certain treatments?

    <p>Bronchi, gastrointestinal tract, and genitourinary tract</p> Signup and view all the answers

    What role do autonomic reflex responses play in nitrate administration?

    <p>They are activated primarily through high doses.</p> Signup and view all the answers

    What is the onset of action for intravenous nitroglycerin?

    <p>Minutes</p> Signup and view all the answers

    What effect does intravenous nitroglycerin have on arterial pressure when the infusion is stopped?

    <p>It is quickly reversed</p> Signup and view all the answers

    Which formulation of nitroglycerin leads to a long duration of blood concentration?

    <p>Transdermal</p> Signup and view all the answers

    What is a potential deleterious effect of using nitrates?

    <p>Increased myocardial oxygen requirement</p> Signup and view all the answers

    Which of the following is a benefit of vasodilation of epicardial coronary arteries?

    <p>Improved perfusion to ischemic myocardium</p> Signup and view all the answers

    What is a common treatment application of intravenous nitroglycerin?

    <p>Severe, recurrent rest angina</p> Signup and view all the answers

    Which of the following can lead to the development of tolerance when using nitroglycerin?

    <p>Long-acting preparations</p> Signup and view all the answers

    What effect may be experienced as a result of oral organic nitrates?

    <p>Reflex increase in contractility</p> Signup and view all the answers

    What is the expected effect on left ventricular diastolic pressure when using nitroglycerin?

    <p>Decreased left ventricular diastolic pressure</p> Signup and view all the answers

    What conclusion can be drawn about the effects of sublingual or chewable isosorbide dinitrate compared to nitroglycerin?

    <p>They are comparable in hemodynamic effects</p> Signup and view all the answers

    Which calcium channel blocker is most likely to cause significant reflex tachycardia in response to hypotension?

    <p>Nifedipine</p> Signup and view all the answers

    What is a potential future role of calcium blockers as suggested by animal research?

    <p>Fertility disorders</p> Signup and view all the answers

    Which adverse effect may result from excessive inhibition of calcium influx by calcium channel blockers?

    <p>Bradycardia</p> Signup and view all the answers

    Which condition do calcium channel blockers have moderate efficacy in treating?

    <p>Raynaud’s phenomenon</p> Signup and view all the answers

    What is a significant toxicity risk associated with calcium channel blockers?

    <p>Serious cardiac depression</p> Signup and view all the answers

    Which calcium channel blocker is noted as less effective than atosiban in preterm labor treatment?

    <p>Nifedipine</p> Signup and view all the answers

    What primary benefit do calcium channel blockers provide in patients with recent myocardial infarction?

    <p>Decrease mortality</p> Signup and view all the answers

    In the management of angina, calcium channel blockers show ______ efficacy compared to beta blockers.

    <p>Less</p> Signup and view all the answers

    Which statement is true regarding the pharmacologic properties of calcium channel blockers?

    <p>The choice of calcium channel blocker should consider specific adverse effects.</p> Signup and view all the answers

    Which condition is less responsive to calcium channel blockers compared to the treatment with beta blockers?

    <p>Stable angina</p> Signup and view all the answers

    Study Notes

    Amyl Nitrite and Nitroglycerin

    • Amyl nitrite is packaged in fragile glass ampules and is considered obsolete for angina due to its unpleasant odor and short duration of action.
    • Nitroglycerin is a smooth muscle relaxant effective across vascular systems, not directly affecting cardiac or skeletal muscle.
    • The half-life of unchanged nitrate compounds is 2-8 minutes, whereas denitrated metabolites can last up to 3 hours.
    • The 1,2-dinitro form of nitroglycerin has the most vasodilatory efficacy.

    Nitric Oxide Mechanism

    • Nitric oxide activates guanylyl cyclase, increasing cGMP levels which leads to smooth muscle relaxation.
    • Autonomic receptors do not play a primary role in the nitrate effect; however, hypotensive doses can trigger reflex responses in the autonomic system.
    • Tolerance to nitrates can arise from reduced sulfhydryl group availability and may be partially mitigated with sulfhydryl-regenerating agents.

    Organ System Effects

    • Nitroglycerin relaxes vascular smooth muscle effectively, with veins showing sensitivity to lower concentrations than arteries.
    • For ischemic coronary areas, eccentric lesions provide better flow compared to concentric atheromas.
    • Intravenous nitroglycerin acts rapidly but has effects that reverse quickly upon stopping the infusion.

    Clinical Implications

    • Nitroglycerin and isosorbide dinitrate exhibit similar hemodynamic effects; however, prolonged use leads to the development of tolerance.
    • Calcium channel blockers, while effective for angina, have significant adverse effects like bradycardia, atrioventricular block, and cardiac arrest.
    • These medications also offer benefits in managing hypertension and supraventricular tachyarrhythmias.

    Additional Therapeutic Agents

    • β-blockers reduce heart rate, blood pressure, and myocardial oxygen demands, contributing positively to treatment for effort angina.
    • New therapeutic agents under investigation include metabolic modulators such as trimetazidine and others that modify myocardial metabolism.
    • Ranolazine is an FDA-approved agent for angina, focusing on altering myocardial energy metabolism to enhance oxygen efficiency.

    Key Considerations

    • For unstable angina, short-acting calcium channel blockers pose a risk for adverse cardiac events and are contraindicated.
    • The clinical management of angina should incorporate patient-specific characteristics, including potential drug interactions and adverse effects, to optimize therapeutic strategies.

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    Related Documents

    Katzung Chapter 12.pdf

    Description

    This quiz explores nicorandil and other investigational antianginal agents, focusing on their mechanisms of action. It discusses the unique delivery method of amyl nitrite and the properties of nitroglycerin. Test your understanding of these critical cardiovascular treatments.

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