Drugs acting on respiratory system Cough antitussive drugs centrally acting peripherally acting Sputum expectorant drugs sputum-diluting drugs mucolytic drugs Asthma antiasthmatic drugs Bronchodilators β receptor agonists theophyllines muscarinic antagonists Anti-inflammatory drugs glucocorticosteroids mediator release inhibitorsDrugs acting on respiratory system Cough antitussive drugs centrally acting peripherally acting Sputum expectorant drugs sputum-diluting drugs mucolytic drugs Asthma antiasthmatic drugs Bronchodilators  receptor agonists theophyllines muscarinic antagonists Anti-inflammatory drugs glucocorticosteroids mediator release inhibitors