Mr Lee, a 58 year old smoker with severe chronic obstructive pulmonary disease (COPD) (FEV₁ 43% predicted), is admitted with an acute exacerbation of COPD for the second time in the past month. He presented to the Accident and Emergency Department with increased productive cough and shortness of breath, similar to prior exacerbations. Physical examination is notable for bilateral inspiratory and expiratory wheezing. His sputum is purulent. He is given continuous nebulizer therapy of bronchodilator and one dose of oral prednisone, but his dyspnea and wheezing persist. Chest X-ray reveals an infiltrate.

a) Name TWO major classes of drugs with one example each that are commonly used as bronchodilators in the treatment of COPD. Describe their mechanisms of action (8 marks)

b) Which class of drugs does prednisone belong to? What is the rationale to use this drug in this patient? (4 marks)

c) Should this patient be treated with antibiotics and if so which class of antibiotics with one example is the most appropriate? State the mechanism of action for the chosen class of antibiotics. (8 marks)