This ppt briefly summaries the major drugs used in the management of respiratory disease and are used in their treatment. We will also have a look at the moa, contraindications, pharmacokinetics of drugs used in their treatment.

1. DRUGS ACTING ON
RESPIRATORY
SYSTEM
BY -:
NITESH KUMAR
B. PHARM 7th SEM
JAIPUR COLLEGE OF PHARMACY
JAIPUR, RAJASTHAN

2. Contents -:
1. Anti- asthmatic drugs
2. Drugs for cough
3. Nasal decongestants

3. ANTI-ASTHMATIC DRUGS
 Asthma is a chronic respiratory disorder in which the
patient has difficulty in breathing.
 The main clinical features are dyspnoea i.e.
breathlessness, intermittent wheezing, tightness in
chest with cough.
 The exact etiology of the asthma may vary but allergy
is generally the underlying cause

4. The main factors that contribute to the difficulty in
breathing are as follows-
 Constriction of bronchial smooth muscles producing
broncho-constriction.
 Increased secretion of thick mucus that adhere the
wall of bronchioles.
 Edema of respiratory mucosa. All these effects cause
obstruction of airway.
Etiology of Asthma
The main cause of asthma is allergy. If patient comes in
contact in allergens due to antigen antibody reaction
destruction of mast cells present in lungs takes place.
Due to destruction of mast cells, chemical
substances like histamine, leukotrines,
prostaglandins are released. These substances
cause constriction of smooth muscle, mucosal edema
& increase bronchial secretions & obstruct airway.

5. TREATMENT OF ASTHMA
Following measures are included in asthma
management as
1. Allergen Avoidance - Avoid the contact of allergens
as
possible.
2. Immunotherapy - It is the way in which small doses
of
allergen is produced. But it is not
preferred as it may produce
anaphylaxis
reaction.
3. Chemotherapy - Once the asthma attack is
produced it
should be treated with drugs. These

6. CLASSIFICATION
1. Bronchodilators
a) Sympathomimetics - E.g. Adrenaline, Ephedrine,
Isoprenaline, Salbutamol, Terbutaline,
Salmetrol
b) Methyl xanthenes - E.g. Theophylline,
Aminophylline
c) Anti cholinergic - E.g. Atropine, Ipratromium
bromide
2. Leukotrine Modifiers - E.g. Monteleukast,
Zafirlukast
3. Mast cell Stabilizers - E.g. Sodium chromoglycolate
4. Anti-inflammatory Corticosteroids

7. BRONCHODILATORS
Bronchodilators when given by appropriate route
relieve symptoms of asthma and improve breathing.
They cause relaxation of the bronchial smooth
muscles and improve pulmonary function.
A. Sympathomimetics-
 These drugs by their β2 agonistic activity cause
relaxation of bronchial smooth muscles.
 Mild to moderate attack of asthma responds rapidly
to aerosol administration of sympathomimetics.
 The selective β2- receptor agonists (e.g. Salbutamol,
Terbutaline) are preferred to the nonselective
sympathomimetics amines like ephedrine,
isoprenaline. Aerosol inhalations provide relief more
rapidly than oral administration.

8.  . These are generally preferred for management of
acute and chronic asthma.
Side effects
Tachycardia, tremor, headache, Insomnia and
used
cautiously in CHF & hyperthyroidism.

9. B. Xanthines
 Theophylline or Aminophylline are chemically related to
caffeine & theobromine.
 These drugs inhibit phosphodiesterase enzyme in
smooth muscles which is responsible for hydrolytic
breakdown of c-AMP.
 Thus it increases c-AMP concentration in the bronchial
smooth muscles producing their relaxation.
 In addition it also inhibits histamine release.
 Thus it leads to removal of obstruction and improve
pulmonary functions in asthma. In addition theophylline
also causes cardiac stimulation & CNS excitation.
Side Effects - Nausea, vomiting, tachycardia,
palpitation.
Dose -: Theophylline - Orally 100-300 mg TID
Aminophylline - Slow I.V. Injection 250-500 mg
Orally 250-500 mg TID

10. C. ANTICHOLINERGICS
Anti- cholinergics like atropine are previously used in
treatment of asthma but due to undesirable side
effects not preferred now days.
2. LEUKOTRINE ANTAGONISTS
 Leukotrines are the important mediators of bronchial
asthma.
 Monteleukast & Zafirleukast competitively
antagonizes leukotrine receptors mediated bronco-
constriction, increased vascular permeability &
eosinophilia.
 These are indicated for prophylaxis therapy of mild to
moderate asthma as alternative to inhaled
corticosteroids. But these are not used to terminate
the asthma episodes.
Dose - Monteleukast 10 mg BID

11. 3. MAST CELL STABILIZERS
 Sodium chromoglycolate is synthetic derivative which
inhibits degranulation / breakdown of mast cells by
allergen stimuli.
 Release of asthma mediators from mast cells is
prevented.
 Long term use of it, decreases the cellular
inflammatory response, reduces bronchial
hyperactivity.
 But it does not interfere with antibody antigen reaction
and not also a bronchodilator hence ineffective if
given during asthma attack.
 It is administered it the form of aerosol by oral
inhalation in dose of 20 mg four time a day.
Side effects - Common side effects are throat irritation
& transient bronco-constriction.

12. 4. ANTI-INFLAMMATORY CORTICOSTEROIDS
 Corticosteroids are used in asthma when other drugs
fail to relieve the symptoms.
 These do not have bronchodilator property but due to
their anti-inflammatory action they improve
pulmonary airway function.
 Their onset of action is slower than that of the
bronchodilators.
 But on chronic treatment with corticosteroid
pulmonary function is improved and frequency and
severity of asthma attacks are reduced.
 The dose of a particular steroid to be used must be
selected on the basis of the severity of asthma.
 Inhalation preparations are very effective as they
reach directly to the site of action and also their
systemic absorption is less.

13. Side effects - Adrenal atrophy, peptic ulcer, diabetes,
osteoporosis & Cushing’s syndrome.
These are contraindicated in systemic fungal
infections.
Dose - Hydrocortisone - Orally 4mg/kg/4-6hrs in severe
attacks
Prednisolone - Started with oral 30-60 mg/day
Beclomethasone - Available in aerosol
preparation in
dose of 10 µg
STATUS ASTHMATICUS
It is serious medical emergency, in which patient has
continued attack of asthma and has marked dyspnea,
cyanosis & dehydration.
Treatment-
 Hydrocortisone hemisuccinate 100mg or equivalent

14.  Intermittent inhalations of nebulised salbutamol and
Ipratromium bromide are given.
 Intermittent humidified oxygen inhalations are given
to reverse pallor.
 Salbutamol / Terbutaline 0.4 mg IM / SC may be
given since inhaled drug may not reach smaller
bronchi due to severe bronco-constriction.
 Suitable antibiotics are given to treat respiratory tract
infection.
 To correct dehydration & acidosis, normal saline
solution with sodium bicarbonate infusion is given.

15. DRUGS FOR COUGH
 Cough is a natural phenomenon. It is a protective
reflex which expels respiratory secretions and
even foreign particles from air passages.
 It occurs due to stimulation of the receptors in
throat, respiratory passage or stretch receptors in
the lungs.
 Cough may be useful (productive) or useless
(non-productive).
 Useless or non-productive cough could be
suppressed.
 Useful i.e. productive cough serves to drain the
airway, its suppression is not desirable, may
even be harmful.
 Apart from specific remedies (antibiotics), cough
may be treated as a symptom (non-specific
treatment)

16. Classification of drugs
1. Pharyngeal Demulcents - E.g. Lozenges, Cough
drops, Linctuses containing syrup, glycerin,
liquorice etc.
2. Expectorants
a) Directly Acting - E.g. Sodium / Potassium
acetate,
Potassium iodide, Guaphensin, Balsam of
tolu.
b) Reflexly Acting - E.g. Ammonium chloride,
Potassium
iodide
c) Mucolytics - E.g. Bromhexine, Ambroxol,
Acetyl cystein
3. Antitussives
a) Opoids - E.g. Codeine, Pholcodeine,
Morphine

17. 1. PHYRYNGEAL DEMULCENTS
 These drugs sooth the throat directly as well as
promoting salivation and reduce afferent impulses
from inflamed / irritated pharyngeal mucosa.
 Thus they remove symptomatic relief in dry cough
arising from throat.
2. EXPECTORANTS
 These are the drugs which increase bronchial
secretion or reduce its viscosity, facilitating its
removal by coughing.
 They believed to loosen cough which becomes less
irritating & more productive.
A . Directly acting Expectorants –
(i) Sodium & Potassium Citrate / Acetate
 These are believed to increase bronchial
secretion by salt action. These are used in dose of

18. (ii) Potassium Iodide
 After absorption it is released by bronchial glands.
 It releases iodide which irritates bronchial glands
increasing volume of secretion.
 This action is not desirable if bronchial mucosa is
acutely inflamed.
 It is dangerous in patients sensitive to iodide and
interferes with thyroid function test.
 Prolonged use may induce goiter & hypothyroidism.
Hence now days it is less popular.
 Dose- 0.2-0.3 gm.
(iii) Guaphenasin –
 On oral administration and after absorption from gut
it is secreted by tracheobronchial glands. Then it
directly increases bronchial secretion & mucosal
cilliary action.

19. B. Reflexly Acting Expectorant
(i) Ammonium salts
 These are gastric irritants, reflexly enhances bronchial
secretion & sweating.
 But expectorant doses of these salts are sub-emetic &
nauseating because of unpleasant taste.
 Dose-0.3-1 gm.
C. Mucolytics
 These are claimed to liquefy sputum and facilitate
expectoration.
 These do not increase bronchial secretions.
Bromhexine
 It is derivative of alkaloid vasicine obtained from
Adathoda vasika.
 It is a potent mucolytic capable of inducing thin
copious bronchial secretion.

20.  It de-polymerizes mucopolysaccharides directly as
well as by liberating lysosomal enzyme.
 Network of fibers in tenacious sputum is broken
liquefying it.
 Dose - Adults- 8mg TDS;
Children- 4mg BD (1-5 Yrs.), 4mg TID (5-10
yrs)
Ambroxol
 It is a metabolite of bromhexin having similar
mucolytic action.
 Dose- 15-30mg TID
3. ANTI-TUSSIVES
 These are the drugs that act through CNS to raise
threshold of cough center or act peripherally in
respiratory tract to reduce cough impulses or both
these actions.

21.  But they aim to control rather than to eliminate cough
(expectorant), used for dry unproductive cough or
cough is unduly tiring, disturb sleep.
A. Opoids
(i) Codeine
 It is an opium alkaloid, qualitatively similar but less
potent than morphine.
 It more selectively acts on cough center and reduce
cough. It suppresses cough for about 6 hrs.
 Abuse liability is low but present, constipation is
main drawback.
 At higher doses respiratory depression &
drowsiness can occur. It is contraindicated in
asthma.
 Dose - Adult 10-30 mg /day
Children (2-6yrs)- 2.5-5mg/day

22. (ii) Pholcodeine
 It is having similar efficacy as antitussive to codeine
and has no analgesic & addiction property. Duration
of action is also longer (12 hrs & more).
 Dose - 10-15 mg/ day.
B. Non- Opoids
(i) Noscapine
 It is a opoid alkaloid of benzo-isoquinoline series.
 It depresses cough & has no narcotic, analgesic or
dependant property.
 It is nearly equipotent antitussive as codeine.
 Side effects - Headache & nausea.
(ii) Dextromethorphan
 It is a synthetic compound having selective
antitussive action as that of codeine. It is devoid of
constipation & addiction liability

23. NASAL DECONGESTANTS
 These are the drugs used to relieve nasal mucosal
congestion accompanying allergic rhinitis, hay fever
& sinusitis.
 These drugs act by vasoconstriction of the mucosal
blood vessels thereby reducing the edema.
 Nasal congestion refers to the inflammation of the
turbinate of the nose caused due to either viral
infection or other causes like allergic rhinitis, cold,
hay fever and sinusitis.
 All these are manifested by sneezing, runny nose,
nasal itching etc.
 Drugs are available in both topical and oral
formulations.

24. CLASSIFICATION: -
A. ORAL DECONGESTANTS
EX – Ephedrine, Phenylpropanolamine,
Pseudoephedrine, Phenylephrine
B. TOPICAL DECONGESTANTS
EX – Ephedrine, oxymetazoline, xylometazoline,
phenylephrine.
Mechanism of actions
1. Oral decongestant
 Decrease nasal congestion related to the common
cold, sinusitis and allergic rhinitis.
 Shrink the nasal mucous membrane by
stimulating the alpha-adrenergic receptors in the
nasal mucous membranes.

25.  The shrinkage results in a decrease in membrane
size
promoting drainage of the sinuses and improving
airflow.
2. Topical nasal decongestants
Imitate the effects of the sympathetic nervous system
to cause vasoconstrictions, leading to decreased
edema and inflammation of the nasal membranes.
INDICATIONS
1. Oral decongestants
 Decrease nasal congestion associated with the
common cold, allergic rhinitis.
 Relief of pain and congestion of otitis media.

26. 2. Topical decongestants
 Relieves discomfort of nasal congestion
associated with the common cold, sinusitis, allergic
rhinitis.
 Relieves pressure of otitis media.
PHARMACOKINETICS
1. Oral decongestants
 Pseudoephedrine is generally well absorbed and
reaches peak levels quickly in 20 to 45 minutes.
 Route – orally Metabolization - Liver
 Onset – 30 mins Excretion - Urine
 Duration – 4-6 hrs
 T ½ - 7 hrs

27. 2. Topical decongestants
 Because these drugs are applied topically, the
onset of action is almost immediate and there is less
chance of systemic effects.
 Route – Topical ( nasal spray )
 Onset – Immediate , Metabolism – Liver
 Duration – 4-6 hrs
 T ½ - 0.4-0.7 hrs , Excretion – Urine
SIDE EFFECTS
 Nasal burning, irritation and dryness afer using
decongestant nasal sprays and nose drops.
 Other side effects that have been reported with
nasal decongestants include feeling sick and
headache.

28.  Oral decongestants may cause anxiety,
restlessness, problems with sleeping, and being
aware of a fast or fluttering heartbeat.
CONTRADICTIONS
 If there is a lesion or erosion in the mucous
membrane
 If used during pregnancy or lactation, caution is
advised.
 Caution should be used in any patient who has an
active infection, including tuberculosis because
systemic absorption would interfere with the
inflammatory and immune response.