A 28-year-old female with a history of asthma has been using a salbutamol (albuterol) inhaler approximately 3 times per week for the past 3 years. She has felt well and has had no symptoms at all until about a month ago. Since then, she has been waking up with asthma symptoms such as wheeze and shortness of breath approximately twice a week, and has had 2 visits to family doctor. As a result, she was prescribed treatment with a combination inhaler containing two classes of drugs used as both a maintenance and needed reliever therapy. 

(a) Which class of drug does salbutamol belong to? Give an overview of its pharmacology, efficacy and safety. 

(2 marks) 

(b) What are the TWO classes of drugs with given names in the inhaler? State the mechanism of action for each class of drugs. What is the requirement for such combination of drugs to be used as needed reliever with maintenance? 

(8 marks) 

(c) Describe TWO benefits of inhalation administration. What is the rationale for such drug combination as both a maintenance and needed reliever therapy? 

(4 marks) 

(d) State THREE side (adverse) effects for each of the two classes of drugs. 

(6 marks)