Antianginal agents : A drug may be classified by the chemical type of the active ingredient or by the way it is used to treat a particular condition. Each drug can be classified into one or more drug classes. Antianginal drugs are used to manage angina by either improving perfusion of the myocardium, reducing the metabolic demand of the heart, or both. Two of the main groups of antianginal drugs are organic nitrates and calcium antagonists. They are vasodilators and improve myocardial perfusion, and reduced metabolic demand of the myocardium. Beta-adrenoreceptor antagonists slow the heart rate therefore reduces metabolic demand of the heart.