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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

4. COUGH ETIOLOGY
1. Upper/Lower Respiratory Tract Infection
2. Postnasal drip due to sinusitis, rhinitis
3. Smoking/Chronic Bronchitis
4. Pulmonary Tuberculosis
5. Asthmatic cough
6. Gastrointestinal reflux
7. Drugs – Captopril and Iodides ……

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