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الشرح

Core Concept: Nitroglycerin is a potent vasodilator used to relieve angina pectoris. When administered via the sublingual route (under the tongue), it is rapidly absorbed through the highly vascularized oral mucosa directly into the systemic circulation. This bypasses the extensive first-pass hepatic metabolism that would otherwise destroy nearly 100% of an oral dose, ensuring a rapid onset of action (1-3 minutes).

Clinical Presentation:

• Indicated for acute episodes of angina pectoris (substernal chest pain, pressure, or squeezing).
• Side effects include headache, hypotension, reflex tachycardia, and dizziness.
• Complications of uncontrolled angina include acute myocardial infarction and fatal arrhythmias.

Diagnosis:

• First-line diagnostic tool: A 12-lead Electrocardiogram (ECG) to identify ischemic ST-T wave changes during chest pain.
• Gold standard diagnostic test: Invasive coronary angiography (cardiac catheterization) to definitively map coronary artery blockages.

Management:

• Acute management: Administering sublingual nitroglycerin (up to 3 doses, 5 minutes apart) while monitoring blood pressure to avoid severe hypotension.
• Gold standard long-term/definitive management: Daily antianginal prophylaxis (beta-blockers, calcium channel blockers), antiplatelet therapy, statins, and revascularization via Percutaneous Coronary Intervention (PCI) or Coronary Artery Bypass Grafting (CABG).