Download lec8.Treatment of Cough

TREATMENT OF COUGH
TREATMENT OF COUGH
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Cough is a useful physiological mechanism
that serves to clear the respiratory passages
of foreign material and excess secretions.
It should not be suppressed ‫ تمنع‬- ‫تكبت‬
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.
TREATMENT OF COUGH
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Chronic cough can contribute ‫ يساهم في‬to
fatigue, especially in elderly patients, in such
situations the physicians should use a drug
that will reduce the frequency or intensity ‫شده‬
of the coughing.
Cough reflex ‫ اقرا الفيسيو للشرح‬is complex,
involving the central and peripheral nervous
systems as well as the smooth muscle of the
bronchial tree.
TREATMENT OF COUGH
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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.
TREATMENT OF COUGH
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Afferent ‫ناقل لالشاره نحو المركز ( المخ او الحبل الشكوكي‬
‫ ) مهمه‬conduction from these receptors is via
fibers in the vagus nerve; central
components of the reflex probably involve
several mechanisms or centres that are
distinct ‫تختلف عن‬from the mechanisms
involved in the regulation of respiration.
TREATMENT OF COUGH
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The drugs that directly or indirectly can affect this
complex mechanism are diverse ‫متنوع‬.
‫ مهمه‬For 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.
COUGH
Forceful release of
air from lungs
Sudden, often
involuntary
(protective) reflex
and major
defensive
mechanism ‫وسيله‬
‫دفاعيه للجسم‬
Cont…..
Causes of cough :
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Expulsion ‫ اخراج‬- ‫ طرد‬of respiratory secretion
or foreign particles or irritant or excessive
mucus from air passages
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Symptom
‫ عرض لمرض قلبي او رئوي‬of an
underlying
respiratory
and/or
cardiovascular pathology ‫مهمه‬
) ‫ اذا بتنبه واحد تكح عشان ينتبه ( اهم وحده‬: ‫السبب االخير‬
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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 diaghramatic, abdominal &
intercostal (ribs) muscles noisy expiration (cough)
‫‪Cough Reflex‬‬
‫اماكن وجودها ‪:‬‬
‫‪-1‬على امتداد القناة‬
‫التنفسيه‬
‫‪-2‬في المعده‬
‫‪ -3‬في الجيوب‬
‫االنفيه‬
Types of cough
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.
Most common causes of cough
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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) ‫الدكتور‬
‫ركز عليها‬
Treatment of Cough
1) Antitussives (cough centre suppressants)
‫ادويه تقوم بحظر مركز السعال في المخ‬
2) Expectorants ‫الطارد للبغلم بواسطه تحويله لماده اخف‬
‫( مما هو عليه فيخرج بسهوله‬Mucokinetics)
3) Mucolytics 2 ‫ نفس فكره رقم‬: ‫المحلل للبلغم‬
4) Antihistamines
5) Bronchodilators
6) Pharyngeal Demulcents ‫الملين‬
1) Antitussives (cough centre suppressants)
Drugs suppress cough & produces
symptomatic relief ‫تعافي من االعراض‬
MOA
Mainly suppress cough centre in medulla (both
central & peripheral effects)
E.g., Opoid drugs (codeine, pholcodeine,
noscapine, dextromethorphan)
Opioid = most effective for cough
i) Codeine
Codeine= prodrug  metabolized to morphine
 It is an alkaloid ‫ ماده قاعديه‬found in
Opium poppy
plant
 Has less addiction ‫ادمان اقل من المورفين‬+
 resp. centre depressant ↓
 Has useful antitussive ‫المضاد للسعال‬
action at low doses (<15 mg)
 Produce drowsiness,
thickening of sputum &
constipation
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ii) Noscapine & Pholcodeine
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Related to papaverine ‫ دواء مريح للعضالت‬: ‫البابافارين‬
Do not have addictive ‫ادماني‬, analgesic ‫& مسكني‬
constipating ‫ امساكي‬properties
Do not interfere ‫ يتعارض مع‬with mucocilliary
movement
Noscapine (15 mg) & pholcodeine (10
mg)=syrup ‫شراب‬
iii) Dextromethorphan
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
2) Expectorants (Mucokinetics)
Act peripherally ‫يعني بعيدا عن المخ‬
 Increase bronchial secretion
OR
 Decrease its viscosity  facilitates its
removal by coughing
 Loose cough ►less tiring ‫ & حدّه‬more
productive
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Cont….
Classification of Expectorants
Classified into
b) Directly acting
E.g., Guaifenesin (glyceryl guaiacolate), Na+ &
K+ citrate or acetate,
b) Reflexly acting
E.g., Ammonium salt
i) Sodium & potassium citrate or
Acetate
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They act directly
Actions: ▲Bronchial secretion by salt action
ii) Guaifenesin
Expectorant ‫ طارد للبلغم‬drug usually taken by
mouth
 Available as single & also in combination
MOA=Increase the volume & reduce the
viscosity of secretion in trachea & bronchi
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iii) Reflexly acting ‫يعني تؤثر على المعده‬
‫مما يؤدي الثر عكسي وهو زياده السيكريشن في‬
‫القصبات االهوائيه وايضا زياده التعرق‬
Ammonium salts
Gastric irritants  reflexly  bronchial
secretions + sweating
3) Mucolytics
Help in expectoration ‫ طرد البلغم‬by liquefy ‫التحويل‬
‫اكثر‬
‫سيوله‬
‫ذو‬
‫لشكل‬
the
viscous
tracheobronchial secretions
E.g., Bromhexine, Acetyl cysteine,
i) Bromhexine
Synthetic derivative of vasicine
vasica)
Cont….
(alkaloid= Adhatoda
MOA of Bromhexine
a)
Thinning
&
fragmentation
mucopolysaccaride fibers
b) ↑ volume & ↓ viscosity of sputum
ii) Acetylcysteine
Given directly into respiratory tract
cont.
of
MOA of acetylcysteine
Opens disulfide bond ‫ رابطه في بروتين البلغم‬in
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
4) Antihistamines
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Added to antitussives/expectorant formulation
Due to sedative ‫ & االثر المهدئ‬anticholinergic 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,
5) Bronchodilators
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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
6) Pharyngeal demulcents ‫مطري‬
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Soothe ‫ يهدئ‬the throat (directly & also by
promoting ‫ تحفيز‬salivation ‫)اللعاب‬
▼ afferent impulses from inflamed/irritated pharyngeal
mucosa
Provide symptomatic relief in dry cough arising from
throat
E.g. lozenges, cough drops, glycerine, liquorice, honey
) ‫العسل ( طب شعبي‬
Specific treatment approach to
cough
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/iprat-
ropium/corticosteroid
5) Postnasal drip (sinusitis)
Antibiotics, nasal decongestants, antihistamines