DR. MARWA SHAALAN
PHARM-D
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Basic functions of the respiratory system
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Breathing (Pulmonary Ventilation) – movement of air in and out of the
lungs
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Inhalation (inspiration) draws gases into the lungs.
Exhalation (expiration) forces gases out of the lungs.
Gas Conditioning – as gases pass through the nasal cavity and paransal
sinuses, inhaled air becomes turbulent. The gases in the air are
• warmed to body temperature
• humidified
• cleaned of particulate matter
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Gas Exchange - respiration
• Supplies body with oxygen
• Disposes of carbon dioxide
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Produces Sounds
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Protects respiratory surfaces
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Site for olfactory sensation
 Respiration
– four distinct processes must
happen
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Pulmonary ventilation – moving air into and out
of the lungs
External respiration – gas exchange between the
lungs and the blood
Transport – transport of oxygen and carbon
dioxide between the lungs and tissues
Internal respiration – gas exchange between
systemic blood vessels and tissues
 Respiratory
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organs
Nose, nasal cavity, and paranasal sinuses
Pharynx, larynx, and trachea
Bronchi and smaller branches
Lungs and alveoli
Figure 21.1

Consists of
Respiratory muscles – diaphragm and
other muscles that promote
ventilation
 Respiratory zone – site of external
respiration – respiratory bronchioles,
alveolar ducts, alveolar sacs, and
alveoli.
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Alveoli cell types
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Type I cells site of gas exchangeand
Type II cells - secrete surfactant
Macrophages
Figure 21.10b
RESPIRATORY DISORDERS
TRIALS
-If it necessary – hospitalization with i/v infusion of
glucocorticosteroids and euphyllin
 Cough
is a useful physiological mechanism
that serves to clear the respiratory passages
of foreign material and excess secretions.
 It should not be suppressed indiscriminately.
 There are, however, many situations in which
cough does not serve any useful purpose but
may, instead only annoy the patient or
prevent rest and sleep.
 Chronic
cough can contribribute to fatigue,
especially in elderly patients, in such
situations the physicians should use a drug
that will reduce the frequency or intensity
‫ شده‬of the coughing.
 Cough reflex is complex, involving the
central and peripheral nervous systems as
well as the smooth muscle of the bronchial
tree.
 It
has been suggested that irritation of the
bronchial mucosa causes
bronchoconstriction, which in turn,
stimulates cough receptors( which probably
represent a specialized type of stretch
receptor) located in the tracheobronchial
passages.
 Afferent
conduction from these receptors is
via fibers in the vagus nerve; central
components of the reflex probably involve
several mechanisms or centres that are
distinct from the mechanisms involved in
the regulation of respiration.
The drugs that directly or indirectly can affect
this complex mechanism are diverse.
-For example , cough may be the first or only
symptom in bronchial asthma or allergy, and in
such cases bronchodilators(e.g., 2 – adrenergic
receptor agonists have been shown to reduce
cough ) without having any significant central
effects, other drugs act primarily on the central
or the peripheral nervous system components of
the cough reflex.

Forceful release of
air from lungs
Sudden, often
involuntary
(protective) reflex
and major
defensive
mechanism
Cont…..
Causes of cough :

Expulsion of respiratory secretion or
foreign particles or irritant or excessive
mucus from air passages

Symptom an underlying respiratory and/or
cardiovascular pathology
A)
B)
Acute cough =lasting<3 weeks
Chronic cough =lasing >8 weeks
Cough may be
i) Un productive (dry) cough OR
ii) Productive cough (sputum)
cont.
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Common cold,
Upper/lower respiratory tract infection
Allergic rhinitis
Smoking
Chronic bronchitis
Pulmonary tuberculosis
Asthma
Gastroesophageal reflux
Pneumonia
Congestive heart failure
Bronchiectasis
Use of drugs (e.g., Angiotensin-converting enzyme inhibitors)
1) Antitussives (cough centre suppressants)
2) Expectorants (Mucokinetics)
3) Mucolytics
4) Antihistamines
5) Bronchodilators
6) Pharyngeal Demulcents
Drugs suppress cough & produces
symptomatic relief
MOA
Mainly suppress cough centre in medulla (both central
& peripheral effects)
E.g., Opoid drugs (codeine, pholcodeine, noscapine,
dextromethorphan)
Opioid = most effective for cough
Codeine= prodrug  metabolized to morphine
 It is an alkaloid found in Opium poppy plant
 Has less addiction
 resp. centre depressant ↓
 Has useful antitussive
action at low doses (<15 mg)
 Produce drowsiness,
thickening of sputum &
constipation

 Related
to papaverine
 Do not have addictive, analgesic & constipating
properties
 Do not interfere with mucocilliary movement
 Noscapine (15 mg) & pholcodeine (10 mg)=syrup
Available in syrup, tablets, spray forms
MOA
NMDA receptor antagonist
Uses
Cough suppressant, temporary relief of cough
caused by minor throat & bronchial irritation
(accompanies with flu & cold), pain relief
Ad Effects= Nausea, vomiting, drowsiness, dizziness,
blurred vision
Act peripherally
 Increase bronchial secretion
OR
 Decrease its viscosity  facilitates its
removal by coughing
 Loose cough ►less tiring & more productive

Cont….
Classified into
b) Directly acting
E.g., Guaifenesin (glyceryl guaiacolate), Na+ &
K+ citrate or acetate,
b) Reflexly acting
E.g., Ammonium salt

They act directly
Actions: ▲Bronchial secretion by salt action
ii) Guaifenesin
 Expectorant
drug usually taken by mouth
 Available as single & also in combination
MOA=Increase the volume & reduce the
viscosity of secretion in trachea & bronchi
Ammonium salts
Gastric irritants  reflexly  bronchial
secretions + sweating
Help in expectoration by liquefy the viscous
tracheobronchial secretions
E.g., Bromhexine, Acetyl cysteine,
i) Bromhexine
Synthetic derivative
Adhatoda vasica)
Cont….
of
vasicine
(alkaloid=
MOA of Bromhexine
a) Thinning & fragmentation of mucopolysaccaride
fibers
b) ↑ volume & ↓ viscosity of sputum
ii) Acetylcysteine
Given directly into respiratory tract
cont.
Opens disulfide bond in mucoproteins of
sputum =↓ viscosity
Uses
Cystic fibrosis (to viscosity of sputum)
Onset of action quick---used 2-8 hourly
Adverse effects
Nausea, vomiting, bronchospasm in bronchial
asthma
Added to antitussives/expectorant formulation
 Due to sedative ‫ &ا‬anticholinergic actions produce
relief in cough but lack selectivity for cough centre
 No expectorant action =▼secretions (anticholinergic
effect)
 Suitable for allergic cough (not for asthma)

E.g.,
Chlorpheniramine,
promethazine
diphenhydramine,
Bronchospasm or stimulation of pulmonary receptors
=
induce
or
aggravate
‫زياده‬
cough
+
bronchoconstriction
 e.g. β2-agonist (salbutamol, terbutaline)

MOA of bronchodilators in cough
 ▲surface velocity of air flow during cough→ Clear
secretions of airway
 ‫مهمه‬Not used routinely for every type of cough but
only when bronchoconstriction is present
Soother
the throat (directly & also by
promoting salivation)
▼ afferent impulses from inflamed/irritated
pharyngeal mucosa
 Provide symptomatic relief in dry cough arising from
throat

E.g. lozenges, cough drops, glycerine, liquorice, honey
Etiology of cough
Treatment
1) Upper/lower respiratory
tract infections
Appropriate
2) Smoking/chronic bronchitis
Cessation of smoking
3) Pulmonary tuberculosis
4) Asthmatic cough
antibiotics
Antibiotics
Inhaled β2-agonists/ipratropium/corticosteroid
5) Postnasal drip (sinusitis)
Antibiotics, nasal decongestants, antihistamines
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THANK YOU