What is Asthma?
Asthma is a chronic inflammatory disorder of the airways disease characterized by increased responsiveness of trachea and bronchi to various stimuli result in inflammation and bronchospasm.
Clinically it is characterized by paroxysms wheeze, dyspnoea, cough, and chest tightness and maybe relieved spontaneously or as a result of therapy.
Common Symptoms of Asthma :
The Common Symptoms included wheezing, coughing, chest tightness, and shortness of breath. Symptoms can range from mild to serve.
Bronchial Asthma :
Bronchial asthma: it is a medical condition, which causes obstruction due to hyper-responsiveness of the tracheobronchial tree to various intrinsic and extrinsic stimuli.
Symptoms include dyspnoea, wheezing, cough, and maybe a limitation of activity.
Asthma or bronchial asthma is recognized by primarily inflammatory conditions: inflammation underlying hyperreactivity.
Cause of Asthma or Bronchial asthma
1. Many trigger factors are infection (bacterial and viral), irritants, pollution, exercise, exposure to cold air, psychogenic conditions.
2. Mast cells ( Present in lungs) and inflammatory cells recruited as a result of the initial reaction produce a multitude of mediators:
- Release of mediators stored in granules (immediate): histamine, protease enzymes, TNF- α(tumor necrosis factor-α)
- Release of phospholipids from cell membrane followed by mediator synthesis (within minutes): PGs (prostaglandins), LTs (Leukotriene), PAF (platelet-activating factor)
- Activation of genes followed by protein synthesis: interleukins, TNF-α
These mediators together constrict bronchial smooth muscle, cause mucosal edema, hyperemia and produce viscid secretions, all resulting in reversible airway obstruction.
3. Asthma or Bronchial asthma is generally induced by allergy or allergens such as:
- Pollen grains,
- Environmental irritants or house dust,
- Animal dandruff,
- Contact with animal hair,
- Stress and anxiety,
- Emotion, exercise,
- Cold or Cold air,
- Intake of Freeze Substances.
Drugs used in the treatment of Asthma or Bronchial Asthma
Treatment of Asthma or Bronchial Asthma consists of
a. sympathomimetics (similar action of adrenaline): Adrenaline, isoprenaline, Ephedrine, Salbutamol, Terbutaline, Bambuterol, Salmeterol, Formoterol.
b. Methylxanthines (directly acting bronchodilators): Theophylline, Aminophylline, Choline theophylline, hydroxyethyl theophylline, Theophylline ethanolate of piperazine, Doxophylline.
c. Anticholinergies (blocks action of Ach on autonomic effects): Atropine methonitrate, ipratropium bromide, tiotropium bromide.
2. Leukotriene antagonists: montelukast, Zafirlukast.
3. Mast Cell Stabilizer: Sodium cromoglycate, ketotifen
a. Systemic: Hydrocortisone, Prednisolone.
b. Inhalation: Beclomethasone dipropionate, Budesonide, Fluticasone propionate, Flunisolide, Ciclesonide.
5. Anti-IgE antibody: Omalizumab.
1. Salbutamol (Albuterol)
- salbutamol is a sympathomimetic, bronchodilator, and antiasthmatic drug.
- Salbutamol is a highly selective Beta-2 agonist.
Mechanism of Action (MOA)
Adrenergic drugs (salbutamol) cause bronchodilation through Beta-2 receptor stimulation —–> Increased CAMP (cyclic adenosine monophosphate)
Formation in bronchial muscle cell——> Relaxation.
Salbutamol relaxes bronchial smooth muscle by action on beta-2-receptors of the bronchi and little effect on the heart rate.
Uses of drugs:
- Mild, moderate, and severe bronchial asthma
- Chronic bronchitis
- Reversible airway obstruction due to asthma or COPD.
- Prevention of exercise-induced bronchospasm
- Chronic obstructive pulmonary disease (COPD)