Respiratory Pharmacology-1 (1) Flashcards
What are the main objectives of studying drugs used to treat respiratory diseases?
To study the drugs used to treat respiratory diseases, their mechanism of action, pharmacokinetics and collateral effects associated with these drugs.
Name three common respiratory diseases.
- Asthma/COPD
- Cough/Cold
- Cystic fibrosis
What is asthma?
A chronic respiratory disorder characterized by airway obstruction (reversible), airway inflammation, airway hyper-responsiveness, and remodelling of the airways.
What are the treatment objectives for asthma?
- Relieve obstruction (bronchodilators)
- Reduce inflammation (steroids)
- Keep airways as open as possible
- Reduce stimuli for hyper-responsiveness
- Reduce exposure to allergens
- Intervene with drugs that reduce allergic response
What is COPD?
Chronic obstructive pulmonary disease, a chronic terminal lung disease that reduces air flow to the lungs.
What are the most common types of COPD?
- Chronic bronchitis
- Emphysema
What is emphysema?
The destruction of the tiny air sacs at the end of the airways in the lungs.
What causes COPD?
- Destruction of parts of the lung
- Mucus blocking the airways
- Inflammation and swelling of the airway lining
- Tobacco smoking (accounts for over 70% of cases in high-income countries)
- Exposure to dusts, fumes, or chemicals in the workplace
- Indoor pollution
- Asthma in childhood
- Alpha-1 antitrypsin deficiency
What are the main categories of drug therapy for asthma and COPD?
- Bronchodilators
- Corticosteroids
- Other drugs (Antibiotics, Mucolytics, PDE-4 inhibitors, Leukotriene antagonists, Monoclonal antibodies)
What is the preferred route of delivery for respiratory drugs?
Inhalation, providing a local effect.
What are common challenges in inhalation delivery?
- High incidences of non-adherence
- Poor inhaler technique
Which receptors mediate bronchial smooth muscle in the lungs?
- Beta-2 (β2) receptors (bronchodilation)
- Muscarinic receptors (bronchoconstriction)
What is the mechanism of action for beta-2 agonists?
G-protein activation leads to adenylate cyclase activation, increasing cAMP which results in bronchodilation.
What is the prototype short-acting beta-2 agonist?
Salbutamol
What are common side effects of short-acting beta-2 agonists?
- Tachycardia
- Palpitations
- Tremor
What is a safety issue associated with long-acting beta-2 agonists (LABA)?
Increased risk of asthma-related death when used without inhaled corticosteroids.
What is the prototype for short-acting muscarinic antagonists?
Ipratropium
What is the mechanism of action for anticholinergics like atropine?
Blocks M3 receptors, reducing intracellular calcium leading to smooth muscle relaxation and bronchodilation.
What are common side effects of anticholinergics?
- Dry mouth
- CNS toxicity
- Tachycardia
- Increased viscosity of mucus secretion
- Impaired mucociliary clearance
What is the prototype methylxanthine?
Theophylline
What are common side effects of methylxanthines?
- Nausea
- Vomiting
- Increased gastric acid secretion
- Polyuria
- Insomnia
- Palpitations
- Headaches
- Tremors
What are corticosteroids?
Synthetic analogs of natural steroid hormones produced by the adrenal cortex, involved in metabolism with immunosuppressive, anti-inflammatory, and vasoconstrictive effects.
What type of receptors do corticosteroids act upon?
They act in the nucleus, promoting expression of some genes and inhibiting others.
What are corticosteroids derived from?
Cortisol
Cortisol is often referred to as the ‘stress hormone’ and is produced by the adrenal glands.
