DRUGS ACTING ON THE RESPIRATORY SYSTEM

CHAPTER FIVE

Please share your latest assessment with the academic support expert to receive the applicable discounted rate.

Learning Objectives

At the end of this chapter, students will be able to:

• Describe major drug groups used in the treatment of bronchial asthma, cough, nasal congestion, and allergic respiratory conditions.
• Outline the classification of drugs used for bronchial asthma.
• Explain the pharmacokinetics, mechanisms of action, and adverse effects of each drug group used in asthma management.

Introduction

The respiratory system includes the nasal passages, pharynx, trachea, bronchi, and bronchioles. Respiration involves gas exchange between the body tissues and the external environment. This process includes inhalation, oxygen uptake in the lungs, oxygen transport in the bloodstream, cellular oxygen utilization, and elimination of carbon dioxide.

Pharmacological management of pulmonary disorders focuses on modifying specific physiological functions. This chapter reviews key drugs used in the treatment of common respiratory conditions, particularly bronchial asthma, allergic responses, and congestion associated with upper airway disorders.

Bronchial Asthma

Bronchial asthma is characterised by increased airway responsiveness to various stimuli, resulting in widespread, variable narrowing of the airways. This narrowing may fluctuate spontaneously or in response to therapy.

Impaired airflow in asthma results from three major abnormalities:

• Contraction of airway smooth muscle
• Thickening of the bronchial mucosa due to oedema and cellular infiltration
• Accumulation of thick, viscid mucus within the airway lumen

Exercise

1. What drugs are used to treat bronchial asthma, and how are they classified?
2. Explain the mechanism of action and pharmacokinetics of methylxanthines.
3. What are the side effects and contraindications of glucocorticoids?
4. What are the differences between antitussives and expectorants? Provide examples.
5. Give examples of decongestant drugs and list their side effects.