2. C O U G H I S A P R O T E C T I V E R E F L E X .
I T S P U RP O S E BE I N G E X P U L S I O N O F
R E S P I R ATO RY S E CRE T I O N S O R F O R E I G N
PAR T I C L E S F R O M AI R PAS S AG E S .
I T O C C U R S D U E TO S T I M U L AT I O N O F M E C H AN O -
O R C H E M O R E C E P TO R S I N T H R O AT,
R E S P I R ATO RY PAS S AG E S O R S T RE TC H
R E C E P TO R S I N T H E L U N G S .
C O U G H M AY B E U S E F U L O R U S E L E S S .
DRUG FOR COUGH
3. C O U G H I S T WO T Y P E S
1 . N O N P R O D U C T I V E C O U G H ( D RY )
2 . P R O D U C T I V E C O U G H ( T E N AC I O U S )
TYPE OF COUGH
4. Non productive:- cough is considered as serving no
useful purpose, rather it increased discomfort to the patient.
For treatment antitussive agents are useful.
Productive cough:-It is characterized by presence of
excessive sputum and may be associated with conditions
such as chronic bronchitis and bronchiectasis.
In this condition expectorants are useful.
5. Expectorants- increase the volume and decrease
the viscosity of secretions to enhance the propulsion of
these secretions upward and outward by ciliary
movement and coughing.
6. 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 cough
7. Common causes of cough:-
1. Upper / lower respiratory tract
infection
2. Allergic rhinitis
3. Smoking
4. Chronic bronchitis
5. Pulmonary tuberculosis
6. Asthma
7. Gastroesophageal reflux
8. Pneumonia
9. Congestive heart failure
10. Bronchiectasis
11. Use of drug :-
i. ACE Inhibitor
ii. Iodine
iii. Beta blocker
iv. Amiodarone
8. Anti tussive – Cough suppressant ( tussis-cough)
Expectorants - Increase volume of mucus secretion
Mucolytic - Reduce viscosity of mucus
Mucokinetic - Increase mobility of cough
10. DRUGS OF COUGH – DEMULCENTS AND EXPECTORANTS
Demulcents
Pharyngeal demulcents sooth the throat &
reduce afferent impulses from the inflamed/ irritated pharyngeal mucosa,
thus provide symptomatic relief in dry cough arising from throat.
Expectorants (Mucokinetics) are drugs believed to increase bronchial
secretion or reduce its viscosity, facilitating its removal by coughing.
Expectorants (Mucokinetics)
11. 1. Na and K citrate - Bronchial Secretion
2. Iodides - Irritation of Bronchial mucosa
3. Guaiphenesin, Vasaka - Enhance Bronchial secretions and
mucociliary functions
4. Ammonium salts – nauseating, reflex stimulation of bronchial
secretion
12. 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
Carbocysteine: Similar to acetylcysteine – administered orally
13. 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(i.e hernia, piles, cardiac
diseasead oculr surgery)
14. ANTITUSSIVE -
Opioids –
CODEINE
An 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)
Dose- 10-30 mg
PHOLCODEINE: No analgesia or
addicting property – longer acting
15. NONOPIOIDS:-
Noscapine(Narcotine):
An Opium alakaloid
Depresses cough, but no analgesic, narcotic or dependence liability.
Equipotent with codeine –useful in spasmodic cough .
It can release Histamine that cause bromchoconstriction so not used in
asthma.
Dose- 15-30 mg.
Dextromethorphan:-
Synthetic – d-isomer (antitussive) and l-isomer (analgesic)
Effective as codeine but no addicting and constipating effect
No impairment of mucocilliary function .
16. Antihistamines:
Chlorpheniramine,
Diphenhydramine and
Promethazine
Action :-
It has Sedative and anticholinergic action.
Useful in allergic cough
BRONCHODILATORS:-
Bronchospasm can induce cough and constriction
Especially in Hyperactivity of Bronchial smooth muscles .
Bronchodilators – relieves cough and improves clearance during cough.