Angina pectoris is characterized as chest pain which results from an imbalance in the coronary vessels where the oxygen demand in the heart is greater than the oxygen supplied to the heart. Nitrate’s action involves the formation of free radical nitric oxide (NO), which interacts with & activates guanylate cyclase. These compounds also decrease peripheral arterial resistance & reduce venous tone, thereby increasing venous capacitance & decreasing venous return to the heart.