etiology, prevention approaches, classification of bronchial asthma, M.O.A. of some important category

1. BRONCHIAL ASTHMA

2. BRONCHIAL ASTHMA
• Chronic inflammatory disorder of airways
• Increase in airway hyperresponsiveness
• Recurrent episodes of wheezing, breathlessness,
chest tightness and cough
• Mostly in early morning

4. Pathophysiology of asthma
On exposure to antigen, antibody generated by β cells
On furthur exposure, IGE bind to mast cells where Ag-Ab complex form
Mast cell synthesis mediated inside it
Degranulation of mast cells and release of LTs and PGs due to rupture of mast cells
Mediator bind to receptor
Causes bronchoconstrictions
Leads to asthma

5. Approaches of treatment
•Anti IGE Antibody
•Synthesis inhibitor ----- Corticosteroids
Zileuton
•Mast cell stablizers
•LT antagonist
•Bronchodilators

7. Bronchodilators:
1.Beta 2 agonist
SABA LABA
Salbutamol Salmetrol
tertbutaline formetrol
M.O.A.: Act via GPCR
Activate adenylylcylase
Increase cAMP
Cause bronchodilation
Used for
asthmatic attack
as well as in
prophylactic use

8. 2. Anticholinergic
Ipratropium bromide (short acting)
Tiotropium bromide (long acting)
Why anticholinergics?
• When patient on β blockers therapy
• Use mainly in COPD

9. 3. Methylxanthine
Theophylline
Aminophylline
Doxophylline
M.O.A.:
• Inhibits adenosine which causes bronchodilation
• Non-specific inhibitor of PDE:
PDE degrade cAMP
Decrease cAMP level
Causes bronchoconstriction

10. Salient feature of theophylline:
• Narrow therapeutic index
• Dose monitoring is neccessary
• Follow zero order kinetics
Omalizumab:
• produced by rDNA technology
• Humanised monoclonal antibody
• Use as add on therapy

12. Drug of choice under specific conditions
• Prophyllacticatic use: oral corticosteroids
• Acute attack: salbutamol
• Exercise induced asthma: corticosteroids
• Drug induced asthma: eg.
NSAIDS induced asthma---- inhaled corticosteroids
• Attack during labour: anticholinergic
• Attack during pregnancy: prednisone

13. Recent advances
1. Aerosols:
• 1 to 5 microns particles suspended in gas
• Aerosol produced in
solution ---- MDI, nebulisers
dry powder---- rotainhaler, spinhaler

14. 2. devices:
• MDI: delivered specific amount of drug to lung
• Rotahaler: device to deliver fine powdered
medication measured out in rotecap capsules
• Spacers: add on device use to increase ease of
administering aerosolised medication from MDI