Antianginal Drugs Pharmacology Flash Cards
Antianginal drugs are a class of medications used to treat angina pectoris, a type of chest pain caused by reduced blood flow to the heart. These drugs work by improving the balance between myocardial oxygen supply and demand. Here's a comprehensive overview of antianginal drugs, their mechanisms of action, and key points to remember:
Nitrates:
Examples: nitroglycerin, isosorbide dinitrate, isosorbide mononitrate
Mechanism: Release nitric oxide, causing vasodilation of veins and coronary arteries
Effects: Reduce preload and afterload, increase coronary blood flow
Uses: Acute angina relief, prophylaxis of angina attacks
Side effects: Headache, hypotension, tolerance with continuous use
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Beta-blockers:
Examples: metoprolol, atenolol, propranolol
Mechanism: Block beta-adrenergic receptors, reducing heart rate and contractility
Effects: Decrease myocardial oxygen demand, increase exercise tolerance
Uses: Long-term angina management, hypertension, post-MI
Side effects: Fatigue, bradycardia, bronchospasm (in susceptible patients)
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Calcium Channel Blockers (CCBs):
Examples: amlodipine, nifedipine, diltiazem, verapamil
Mechanism: Block calcium influx into smooth muscle and cardiac cells
Effects: Vasodilation, reduced heart rate and contractility (some agents)
Uses: Angina prophylaxis, hypertension, arrhythmias (some agents)
Side effects: Peripheral edema, constipation, headache
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Ranolazine:
Mechanism: Inhibits late sodium current in cardiac cells
Effects: Reduces intracellular calcium overload, improves diastolic relaxation
Uses: Chronic angina, add-on therapy
Side effects: Dizziness, headache, constipation
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Ivabradine:
Mechanism: Selective inhibitor of the If current in the sinoatrial node
Effects: Reduces heart rate without affecting contractility or blood pressure
Uses: Chronic stable angina in patients with normal sinus rhythm
Side effects: Visual disturbances, bradycardia
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Trimetazidine:
Mechanism: Metabolic modulator, shifts cardiac metabolism from fatty acid to glucose oxidation
Effects: Improves myocardial efficiency, reduces oxygen demand
Uses: Add-on therapy for chronic stable angina
Side effects: Gastrointestinal disturbances, rare cases of parkinsonism
Key points to remember:
Nitrates are the first-line treatment for acute angina attacks
Beta-blockers and CCBs are commonly used for long-term angina management
Combination therapy may be necessary for optimal symptom control
Consider underlying causes (e.g., coronary artery disease) and address risk factors
Monitor for side effects and adjust therapy as needed
Some antianginal drugs have additional indications (e.g., hypertension, arrhythmias)
Educate patients on proper medication use, especially for sublingual nitroglycerin
Encourage lifestyle modifications (e.g., smoking cessation, exercise) alongside pharmacotherapy
Be aware of potential drug interactions, especially with medications that affect heart rate or blood pressure
Regular follow-up is essential to assess treatment efficacy and adjust therapy if necessary
Understanding the pharmacology of antianginal drugs is crucial for healthcare professionals to provide optimal care for patients with angina pectoris. Each class of medication offers unique benefits and potential side effects, allowing for tailored treatment approaches based on individual patient needs and comorbidities.