Choose the literary term that best matches the definition pr…

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Questions

Chооse the literаry term thаt best mаtches the definitiоn provided.

DRUG THERAPY OF CORONARY ARTERY DISEASE   β-Blоckers (BBs) Exаmples Selective β1 (cаrdiоselective): Metоprolol, Atenolol Non-selective β1 + β2: Proprаnolol Mixed β1, β2 + α1: Carvedilol Mechanism / Rationale β-blockers improve myocardial oxygen balance by: ↓ Myocardial O₂ demand ↓ Contractility ↓ Heart rate (↓ SA node automaticity) ↓ AV node conduction → ↓ HR ↑ Myocardial O₂ supply Prolong diastole → ↑ coronary perfusion time Uses Stable angina (prophylaxis + treatment) Acute coronary syndrome (ACS) if no contraindications: Avoid in shock, severe bradycardia, heart block, decompensated HF Often combined with nitrates → prevents reflex tachycardia Contraindications / Important cautions Prinzmetal (vasospastic) angina Non-selective β-blockers are contraindicated: Block β2 vasodilation → unopposed α1 vasoconstriction → coronary vasospasm → may precipitate MI Cocaine-associated chest pain Non-selective β-blockers worsen vasospasm: Cocaine ↑ catecholamines → unopposed α activity → severe vasoconstriction   Organic Nitrates Examples Nitroglycerin (GTN) Isosorbide dinitrate Isosorbide mononitrate Mechanism / Rationale ↓ Myocardial O₂ demand Venodilation → ↓ preload Arterial dilation → ↓ afterload ↑ Myocardial O₂ supply Coronary vasodilation → ↑ blood flow Redistributes blood to ischemic regions Antiplatelet effect (transdermal NG) ↓ platelet aggregation via inhibition of GPIIb/IIIa binding Uses Acute angina relief: Sublingual nitroglycerin → relief in 2–5 min May repeat every 5 min up to 3 doses Chronic stable angina prophylaxis (long-acting forms) ACS with persistent chest pain Acute HTN emergencies, acute decompensated HF (IV nitroglycerin)   Calcium Channel Blockers (CCBs) Mechanism / Rationale ↓ Myocardial O₂ demand ↓ preload and afterload (vasodilation) ↓ contractility (especially non-dihydropyridines) ↓ heart rate (↓ SA node) ↓ AV node conduction ↑ Myocardial O₂ supply Coronary vasodilation → improved perfusion Clinical Uses Stable angina (alternative or adjunct to β-blockers) Prinzmetal (vasospastic) angina (very important indication) Long-acting formulations preferred Short-acting nifedipine should be avoided alone (risk of reflex tachycardia) Combination therapy With β-blockers → prevents reflex tachycardia With nitrates → non-dihydropyridines help blunt tachycardia   Ranolazin Mechanism / Rationale Acts specifically on ischemic myocardium: Inhibits late Na⁺ current during repolarization→ ↓ intracellular Na⁺→ ↓ Ca²⁺ overload (via Na⁺/Ca²⁺ exchanger)→ ↓ intracellular Ca²⁺ Net effects: Improves myocardial metabolism ↓ contractility → ↓ O₂ demand Antiarrhythmic effects (Class Id): ↓ automaticity ↓ early afterdepolarizations (EADs) Key advantage: does NOT significantly affect HR or BP Pharmacokinetics Oral administration Metabolized via CYP3A → significant drug interactions Renal excretion Uses Chronic stable angina (especially when HR/BP limit other drugs) Adjunct in refractory angina Some use in ventricular arrhythmias (off-label) Adverse Effects Common: Nausea Dizziness Headache Constipation Serious: QT interval prolongation → risk of torsades de pointes Contraindication Avoid with other QT-prolonging drugs   Question: A 54-year-old man presents with episodic chest pain that occurs at rest, often in the early morning. ECG during pain shows transient ST-segment elevation. He is diagnosed with Prinzmetal (vasospastic) angina. Which of the following medications is contraindicated because it may worsen his condition?

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