2a. Introduction to Respiratory system & Diseases & Drugs.ppt

Introduction of Drugs for respiratory medicine

1. Drugs affecting Respiratory System
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Dr.R.Rao Prethendhira Singh.
BDS., Msc Med.Pharmacology.PGDCR
Dept.of Pharmacology.

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4. PHYSIOLOGY OF RESPIRATION
•Respiration is the exchange of gases between the tissue of the body
and to outside environment.
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5. Innervation of respiratory system
Parasympathetic supply
M3 receptors in smooth muscles and glands.
Bronchoconstriction
Increase mucus secretion
No sympathetic supply but B
2 receptors in smooth muscles and
glands.
Bronchodilation
Decrease mucus secretion

7. Pulmonary Diseases
•Bronchial Asthma
•Acute Severe Asthma
•Chronic Asthma
•Acute bronchitis
•Chronic bronchitis and emphysema
•Chronic obstructive pulmonary disease
•Respiratory failure
•Cough
•α1-Antitrypsin deficiency
•Drug-induced pulmonary disease
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8. Asthma
Asthma is a chronic inflammatory disorder
of airways that result in airway
obstruction in response to external
stimuli.
It’s characterized by activation of mast cell,
infiltration of eosinophil, T2 helper cells,
Innate type 2 lymphocytes.
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9. Bronchial asthma
•Bronchial asthma is characterized by
hyperresponsiveness of tracheobronchial smooth muscle
to a variety of stimuli, resulting in narrowing of air
tubes, often accompanied by increased secretion,
mucosal edema and mucus plugging.
•Symptoms include dyspnoea, wheezing, cough and may
be limitation of activity.
•Infection, irritants, pollution, exercise, exposure to cold
air, psychogenic.
•Extrinsic asthma: It is mostly episodic, less prone to
status asthmaticus.
•Intrinsic asthma: It tends to be perennial, status
asthmaticus is more common.
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10. Bronchial asthma
•Acute Asthma. It is characterized by episodes
of dyspnoea associated with expiratory
wheezing.
•Chronic Asthma. There is continuous wheeze
and breathlessness on exertion; cough and
mucoid sputum with recurrent respiratory
infection are common.
•Status Asthmaticus (Acute Severe Asthma).
When an attack of asthma is prolonged with
severe intractable wheezing, it is known as
acute severe asthma.
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11. Causes
Exogenous chemicals or irritants
Chest infections
Stress
Exercise (cold air)
Pets
Seasonal changes
Emotional conditions
Some drugs as aspirin, β-bockers

12. Pathophysiology
•Mast cells (present in lungs) and inflammatory cells recruited
as a result of the initial reaction produce a multitude of
mediators by the following processes
•Release of mediators stored in granules (immediate):
histamine, protease enzymes, TNF.
•Release of phospholipids from cell membrane followed by
mediator synthesis (within minutes): PGs, LTs, PAF.
•Activation of genes followed by protein synthesis (over
hours): Interleukins, TNF
•These mediators together constrict bronchial smooth muscle,
cause mucosal edema, hyperemia and produce viscid
secretions.
•All resulting in reversible airway obstruction.
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14. Airways of the asthmatic patients are characterized
by:
1.Inflammation
•Swelling
•Thick mucus production.
2.Bronchospasm
•constriction of the muscles around the airways,
causing the airways to become narrow.
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15. Airway hyper-reactivity: abnormal sensitivity of the airways to wide range of
external stimuli as pollen, cold air and tobacco smoke.
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16. Symptoms of asthma
Asthma produces recurrent episodic attack of
Acute bronchoconstriction (immediate)
Shortness of breath
Chest tightness
Wheezing
Rapid respiration
Cough
Symptoms can happen each time the airways
are irritated.
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17. CLASSIFICATION OF ANTIASTHMATIC DRUGS
1. Bronchodilators
(a) Sympathomimetics
•Selective Beta 2-adrenergic agonists: Salbutamol and
terbutaline (short acting);
bambuterol, salmeterol and formoterol (long acting).
(b) Methylxanthines: Theophylline, aminophylline, etophylline,
doxophylline.
(c) Anticholinergics: Ipratropium bromide, tiotropium bromide.
2. Leukotriene receptor antagonists: Zafirlukast, montelukast,
zileuton.
3. Mast cell stabilizers: Sodium cromoglycate, ketotifen.
4. Glucocorticoids
(a) Inhaled glucocorticoids: Beclomethasone, budesonide,
fluticasone, ciclesonide.
(b) Systemic glucocorticoids: Hydrocortisone, prednisolone,
methylprednisolone.
5. Anti-IgE monoclonal antibody: Omalizumab.
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20. Cough
•Protective reflex.
•Intended to remove irritants and accumulated secretion.
•Types of cough:
1. Productive cough: helps to clear the airway, suppression is
harmful may leads to infection.
2. Non productive cough: Useless and should be suppressed.

21. Mechanism of
cough
•Stimulation of mechano-or chemoreceptors
(throat, respiratory passages or stretch receptors in
lungs)
•Afferent impulses to cough centre (medulla)
•Efferent impulses via parasympathetic & motor
nerves to diaphragm, intercostal muscles & lung
•Increased contraction of diaphragmatic, abdominal
& intercostal (ribs) musclesNoisy expiration
(cough)

22. Drugs for
cough
•Cough can be treated as a symptom (nonspecific therapy) or with
specific remedies (antibiotics, etc.)
•Nonspecific therapy
1.Pharyngeal demulcents: Lozenges, cough drops, linctuses
containing syrup, glycerine, liquorice.
2.Expectorants (Mucokinetics)
(a)Bronchial secretion enhancers: Sodium or Potassium citrate,
Potassium iodide, Guaiphenesin (Glyceryl guaiacolate), balsum
of Tolu, Vasaka, Ammonium chloride.
(b)Mucolytics: Bromhexine, Ambroxol, Acetyl cysteine,
Carbocisteine

23. 3. Antitussives (Cough centre suppressants)
(a)Opioids: Codeine, Ethylmorphine, Pholcodeine.
(b)Nonopioids: Noscapine, Dextromethorphan, Chlophedianol.
(c)Antihistamines: Chlorpheniramine, Diphenhydramine,
Promethazine.
(d)Peripherally acting: Prenoxdiazine.
4. Adjuvant antitussives Bronchodilators: Salbutamol,
Terbutaline

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