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Questions and Answers
What is the primary therapeutic action of B₂-agonists in anti-asthmatic treatment?
Which of the following is an example of a long-acting B₂-agonist?
What is a notable side effect associated with short-acting B₂-agonists?
Which category of anti-asthmatic drugs includes Tiotropium bromide?
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Which type of drug lasts up to 12 hours and is primarily used for maintenance therapy of asthma?
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Which type of asthma is most likely to occur due to allergen exposure in individuals with a family history of allergies?
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What underlying factor is commonly associated with intrinsic asthma?
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Which of the following mediators is primarily responsible for bronchospasm in asthma?
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Which of the following is NOT a common trigger for asthma attacks?
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What is a characteristic feature of mixed asthma?
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What primarily characterizes asthma as a pulmonary disorder?
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Which cells are primarily involved in the inflammatory process of asthma?
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Which mechanism is responsible for bronchoconstriction in the lungs?
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What is a common clinical symptom experienced by asthma patients?
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What physiological process occurs during bronchodilation?
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What is one of the primary mechanisms through which B₂-agonists induce smooth muscle relaxation in the airways?
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Which of the following is a pharmacological action of B₂-agonists?
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What is a common therapeutic use of B₂-agonists?
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Which adverse effect is specifically noted for high doses of B₂-agonists?
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What condition is a contraindication for the use of B₂-agonists?
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How do B₂-agonists affect calcium levels in relation to bronchial smooth muscle relaxation?
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What effect does the stimulation of B₂-adrenoceptors have on skeletal muscles?
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Which B₂-agonist can be used as a single agent for preventing exercise-induced bronchospasm in individuals without persistent asthma?
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Study Notes
Introduction to Asthma
- Asthma is a chronic respiratory disease caused by inflammation and narrowing of the airways.
- Inflammation involves immune cells, including eosinophils, mast cells, neutrophils, T-lymphocytes, and macrophages.
- Asthma can be triggered by irritants, infections, stress, and unknown factors.
Types of Asthma
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Extrinsic Asthma (Allergic Asthma): triggered by allergens like dust, pollen, and animal dander.
- Often linked to family history of allergies.
- Intrinsic Asthma (Non-Allergic/Idiosyncratic Asthma): caused by neurological imbalances, infections, exercise, emotional stress, or chronic pulmonary infections.
- Mixed Asthma: a combination of intrinsic and extrinsic factors.
Causes of Asthma
- Atopy: genetic predisposition to develop IgE reactions to common allergens.
- Other Factors: dust mites, animal dander, molds, pollens, fungi, fossil fuels, cockroaches, strong fumes, cigarette smoke, sprays, cold weather, viral infections, exercise, rhinitis, sinusitis, certain medications, GERD, and environmental pollutants.
Pathological Changes in Asthma
- Bronchospasm: caused by contraction of bronchial smooth muscles, triggered by histamine, leukotrienes, prostaglandins, PAF, and bradykinin.
- Mucus Secretion: increased by histamine, prostaglandins, leukotrienes, PAF, bradykinin, and eosinophils.
- Mucosal Edema: caused by bradykinin, PAF, leukotrienes, histamine, and PGE₂.
- Airway Hyper-reactivity: occurs due to inflammatory factors involved in anaphylaxis, neutrophil chemotactic factors, PAF, and LTB₄.
Classification of Anti-Asthmatic Drugs
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B₂-Agonists (Sympathomimetics): relax smooth muscles in the airways.
- Short-Acting B₂-Agonists: rapid action, lasting up to 6 hours (e.g., salbutamol, terbutaline).
- Long-Acting B₂-Agonists: slower onset, lasting up to 12 hours (e.g., salmeterol, formoterol).
- Anticholinergics: block acetylcholine, leading to bronchodilation (e.g., tiotropium, oxitropium, ipratropium).
- Methylxanthines: relax smooth muscles, enhance mucociliary clearance (e.g., theophylline, aminophylline).
- Leukotriene Receptor Antagonists: block leukotrienes, reducing inflammation (e.g., zafirlukast, montelukast).
- Corticosteroids: reduce inflammation (e.g., beclomethasone, budesonide, fluticasone).
- Mast Cell Stabilizers: reduce mast cell degranulation (e.g., nedocromil, cromolyn sodium).
- Anti-IgE Monoclonal Antibody: blocks IgE binding to mast cells (e.g., omalizumab).
B₂-Agonists (Sympathomimetics)
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Mechanism of Action:
- B₂-agonists activate adenyl cyclase through Gs protein, increasing cAMP production.
- cAMP relaxes smooth muscles and decreases calcium concentration.
- B₂-agonists increase K⁺ channel conductance, hyperpolarizing the smooth muscles, promoting relaxation.
- B₂-agonists activate adenyl cyclase through Gs protein, increasing cAMP production.
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Pharmacological Actions:
- Increased mucociliary clearance.
- Inhibition of mediators released from mast cells and monocytes.
- Reduced calcium release and entry into smooth muscle cells, leading to bronchodilation.
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Therapeutic Uses:
- Treatment of acute bronchospasm.
- Maintenance therapy for asthma.
- Management of bronchospasm associated with COPD, emphysema, chronic bronchitis, and exercise-induced asthma.
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Adverse Effects:
- Headache, anxiety, nervousness, palpitation, dry mouth, tremors, tachycardia, arrhythmias, hypokalemia, hypomagnesemia, hyperglycemia, paradoxical bronchospasm, and increased severity of asthma episodes.
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Contraindications:
- Hypersensitivity, uncontrolled arrhythmias, coronary artery disease, and prior history of hypersensitivity.
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Description
This quiz covers the basics of asthma, a chronic respiratory condition characterized by airway inflammation and narrowing. It delves into the different types of asthma, including extrinsic, intrinsic, and mixed forms, as well as the various triggers and causes associated with the disease.
