Isonorm 20 Tablet contains Isosorbide Mononitrate 20 mg, a nitrate vasodilator primarily used in the prevention and management of angina pectoris due to coronary artery disease. Isosorbide Mononitrate acts by relaxing vascular smooth muscle, leading to vasodilation, which reduces myocardial oxygen demand by decreasing preload and afterload. This mechanism helps alleviate chest pain associated with reduced blood flow to the heart. Isonorm 20 is indicated for the prophylactic treatment of chronic stable angina and may also be used in other conditions requiring vasodilation under medical supervision. The tablet is administered orally, with dosing tailored according to clinical response and patient tolerance. Common side effects include headache, dizziness, hypotension, and flushing, which are generally dose-dependent and tend to diminish with continued use. Caution is advised in patients with hypotension, severe anemia, or increased intracranial pressure. Concomitant use with phosphodiesterase inhibitors is contraindicated due to the risk of severe hypotension. Regular monitoring of blood pressure and clinical status is recommended during therapy. Isonorm 20 should be used under strict medical guidance to optimize therapeutic outcomes and minimize adverse effects.