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Chapter 16: Drug Therapy of Myocardial Ischemia

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The antianginal drug of choice to use in a patient with vasospastic angina who has sinus bradycardia is

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a. propranolol.

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b. verapamil.

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c. diltiazem.

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d. amlodipidine.

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e. nitroglycerin.

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Answer is d. Amlodipine is the drug of choice to use in this patient. β Adrenergic blockers, verapamil, and diltiazem will all slow his heart rate by inhibiting SA nodal activity, which will exacerbate his sinus bradycardia. Although nitroglycerin will not inhibit SA nodal activity, it is not as effective as a dihydropyridine in preventing the symptoms of angina in a patient with vasospastic angina.

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A patient with chronic exertional angina is refractory to combination therapy with a β blocker, organic nitrate, and Ca2+ channel blocker. Which of the following drugs may be useful in reducing the symptoms of angina in this patient?

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a. A PDE5 inhibitor

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b. Aspirin

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c. Heparin

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d. A statin

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e. Ranolazine

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Answer is e. Ranolazine is an antianginal agent reserved for use in patients who are refractory to treatment with other antianginal agents. It has a unique mechanism of action that reduces myocardial O2 demand without affecting hemodynamics. It appears to act by blocking the late inward Na+ current (late INa) in ventricular myocytes, which in turn reduces intracellular concentrations of Na+ during diastole. Lowering intracellular Na+ facilitates efflux of Ca2+ from myocytes through the Na+-Ca2+ exchanger. The reduction in intracellular Ca2+ facilitates relaxation of ventricular myocytes and reduces O2 demand. Ranolazine would be added to the antianginal therapy this patient is receiving.

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The mechanism underlying the life-threatening interaction of organic nitrates and PDE5 inhibitors is that

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a. PDE5 inhibitors block the degradation of organic nitrates in the liver.

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b. PDE inhibitors block the degradation of cyclic GMP in vascular smooth muscle.

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c. PDE inhibitors enhance the conversion of organic nitrates to NO.

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d. PDE5 inhibitor degradation is blocked by organic nitrates.

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e. PDE5 inhibitor excretion is blocked by organic nitrates.

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Answer is b. PDE5 inhibitors inhibit the degradation of cyclic GMP in vascular smooth muscle cells which increases the intracellular concentration ...

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