1. DRUGS FOR COUGH
Dr. D. K. Brahma
Associate Professor
Department of Pharmacology
NEIGRIHMS, Shillong
2. WHAT IS COUGH ?
It’s a protective reflex – for expulsion of
respiratory secretions and foreign
particles from air passages
Respiratory secretions ! – URT - LRT
Stimulation of mechano or chemoreceptor
– throat, respiratory passages and stretch
receptors in the lungs
Afferent fibres in vagus & sympathetic -
impulses to cough center – medulla
Cough Mechanism !
3. COUGH – TYPES AND MERITS
Non-productive (Dry Cough) and Productive
Nonproductive ones need suppression –
cerebral hypoxia, rupture of bullas and fracture
ribs etc.
Productive – needs to clear airway
May be harmful if suppressed !
Amount of product Vs effort of coughing
Most of the time, coughing is beneficial
Removes excessive secretions
Removes potentially harmful foreign substances
In some situations, coughing can be harmful, such as
after hernia repair surgery
5. COUGH – DRUGS (NONSPECIFIC)
1. PHARYNGEAL DEMULCENTS: Lozenges, cough
drops, linctuses glycerine and liquorice
2. EXPECTORANTS: (MUCOKINETICS – secretion
enhances):
a) Secretion Enhancers: Sodium and Potassium citrate, KI,
Guaiphenesin (Glyceryl guaicolate), Vasaka, Ammonium
chloride
b) Mucolytics: Bromhexine, Ambroxol, Acetylcysteine,
Carbocysteine
3. CENTRAL COUGH SUPPRESSANTS:
a) Opioids: Codeine, Pholcodeine
b) Nonopioids: Noscapine, Dextromethorphan
c) Antihistamines: Chlorpheniramine maleate,
Diphenhydramine,promethazine
4. ADJUVANT: Salbutamol, Terbutaline
6. DRUGS OF COUGH – DEMULCENTS
AND EXPECTORANTS
Demulcents
Soothing effect and symptomatic relief – reduce
afferent impulses - act by increasing flow of saliva
Expectorants (Mucokinetics)
1. Increase Bronchial Secretion – Na and K citrate
2. Irritation of Bronchial mucosa – Iodides
3. Enhance Bronchial secretions (and mucociliary
functions) – Guaiphenesin, Vasaka
4. Ammonium salts – nauseating, reflex stimulation
of bronchial secretion
7. ACTIONS OF DRUGS OF COUGH –
MUCOLYTICS
Bromhexine: Derivative of Adhatoda vasica
(Vasaka) – increases bronchial secretion
Depolymerises mucopolysaccharides in bronchial
secretions – directly or by liberating lysosomal
enzyme
Fibres of sputum breaks down
Useful in mucus plug
Ambroxol: Similar to Bromhexine
Acetylcysteine: Breaks sulfide bond in
mucopolysaccharides of bronchial secretions –
Respiratory tract administration
Carbocysteine: Similar to acetylcysteine –
administered orally
8. ACTIONS OF DRUGS OF COUGH -
ANTITUSSIVES
Action via CNS
Act by raising the threshold of cough centres
Also periphery – by reducing cough impulse
Uses:
dry and nonproductive cough
Unusually tiring cough, disturbed sleep or hazardous
– hernia, piles, cardiac diseasead oculr surgery
9. ANTITUSSIVE - CODEINE
Opioid – opium alkaloid – methyl morphine
Partly converts to Morphine
Less potent than Morphine and degree of
analgesia is equivalent to Aspirin (60 mg)
But, more selective for cough centers and action
lasts for 6 Hours
Blocked by Naloxone
Low abuse liability
Drawbacks: constipation, respiratory
depression and drowsiness (Higher doses)
PHOLCODEINE: No analgesia or addicting
property – longer acting
10. COUGH DRUGS - NONOPIOIDS
Noscapine: Opium alakaloid
Depresses cough, but no analgesic, narcotic or
dependence liability
Equipotent with codeine – spasmodic cough
Histamine release – no in asthma
Dextromethorphan:
Synthetic – d-isomer (antitussive) and l-isomer
(analgesic)
Effective as codeine but no addicting and constipating
effect – No impairment of mucocilliary function
But, dissociative effect – recreational drug?
In Combination – Paracetamol (acetaminophen)
11. COUGH DRUGS
Antihistamine:
Chlorpheniramine, Diphenhydramine and
Promethazine
MOA: Sedative and anticholinergic
Useful in allergic cough
Bronchodilators:
Bronchospasm can induce cough and
constriction
Hyperactivity of Bronchial smooth muscles
Bronchodilators – relieves cough and improves
clearance during cough
12. THANK YOU/KHUBLEI SHIBUN
Cough syrups, remedies for cough and cold are
FREELY AVAILABLE
however, needs rational prescribing