Bronchial asthma patho-physiology and pharmacological drug classification

1. Bronchial asthma
Pathophysiology and drug classification
By: Dr chinmaya debasis panda

2. At a glance
• Introduction
• pathophysiology of bronchial asthma
• Classification of drugs

3. Introduction:
• Asthma is a chronic inflammatory disease of the airways that is
characterized by :
Activation of mast cells
infiltration of eosinophils
and T helper 2 (TH2) lymphocytes
• Usually accompanied by:
Bronchial hyperactivity & bronchospasm
Increased secretion
Mucosal edema
Mucus plug
• Characteristics:
excessive narrowing of airways with caugh
reduced airflow and
symptomatic wheezing and dyspnea

4. Etiology:
Genetic
Developemental
Environmental
Inflamatory
Imunological

5. Pathophysiology:
1. Inflammation &
2. Re-modelling of airways
Hallmark:
lymphocyte directed eosinophilic bronchitis
Asthmatic diathesis(bronchial hyper-responsiveness)
Clinically silent during basal state
Mediators:
Granules: histamine,heparin,tryptase,chymotrypsin,protease
Membrane lipids: sulfidopeptide, leukotrienes, prostaglandins, PAF
Cytokines: TNFα, leukotrienes(3,4,5,13)

6. S
E
N
S
I
T
I
S
A
T
I
O
N

8. Steps:
Antigen/allergens exposure(house dust, mites, fur, pollens, rodents)
Cross-linking of IgE on mast cell surface(sensitization)
Activation and degranulation of mast cells

9. Release of mediators
Immediate bronchial reactions
(Early reaction)
Bronchospasm, local vasodilatation, increased capillary permeability,
edema, chemotaxis
(Rapid onset, peaks in 15-30 minutes, recovery in 24 hrs)

10. Release of inflammatory mediators by newly arrived cells
Aggravation of airways inflammation &
sustained bronchoconstriction
(late phase reaction)
(bronchoconstriction begins in 4-6hrs & lasts up to 24 hrs)
Bronchial hyper rensponsivenes may last up to 2 wks
Incomplete recovery & repair - remodeling & persistent obstruction of
airways
(chronic asthma)

12. An attack of bronchial asthma may also be triggered by
Viral infections
Cold air
Exercise
Drugs
Chemicals
Histamine etc

14. Drug classification:
I. Bronchodilators
1. Selective β2 adrenergic receptor agonists:
• Short acting: albuterol (salbutamol), levalbuterol, metaproterenol,
terbutaline, fenoterol, tulobuterol, rimiterol, and pirbuterol.
• Long acting: Salmeterol, Formoterol
2. Non selective β2 adrenergic receptor agonists:
Orciprenaline, Adrenaline, Ephedrine

15. 3. Phosphodiesterase inhibitors:
Theophylline (anhydrous), Aminophylline, Choline theophyllinate,
Hydroxyethyl theophylline, Theophylline ethanolate of piperazine,
Doxophylline
4. Anticholinergics:
Ipratropium bromide, Tiotropium bromide.

16. II. Anti-inflammatory drugs:
1. corticosteroids:
A. Systemic: Hydrocortisone, Prednisolone and others.
B. Inhalational: Beclomethasone dipropionate, Budesonide,
Fluticasone propionate, Flunisolide, Ciclesonide.
2. Leukotriene modifiers:
A. LT antagonist: Montelukast, Zafirlukast
B. LT synthesis inhibitors: Zileuton

17. 3. Mast cell stabilizers:
Sodium cromoglycate, Nedocromil, Ketotifen.
III. Anti-IgE antibody
Omalizumab