The expectorant helps thin and loosen mucus in the lungs, making it easier to cough up the mucus.Antitussives, also known as cough suppressants, help prevent coughing by working on a part of the brain that controls the action. Coughing is an innate reflex and part of the immune system’s response to get rid of foreign objects. Antitussives help suppress the urge to cough.

1. EXPECTORANTS & ANTITUSSIVES
Prepared by:
Kakade Samrudhi &Throat Pragati
Guided by:
Asst. Prof. Sidwadkar.I.H
(Pharmacology Department)
SCHOOL OF PHARMACY & RESEARCH CENTER
BARAMTI

2. Expectorants and antitussives are those drugs that are used to treat cough.
Cough : it is a protective reflux , it’s purpose being expulsion of respiratory
secretions and forging particles from air passages.
Pharyngeal demulcent: pharyngeal demulcent soothe the throat and reduce
afferent impulses from the inflamed pharyngeal mucosa , thus provide
symptomatic relief in dry cough arising from throat.
Expectorants: they are also known as mucokinetics. These are those drugs which
believed to increase bronchial secretions or reduce it’s viscosity, facilitating its
removal by coughing.
Antitussives: these are drugs that act in the CNS to raise the threshold of cough
centre or act peripherally in respiratory tract or reduce tussal impulses, or both
these actions.

3. CLASSIFICATION

4. MECHANISM OF ACTION
I. PHARYNGEAL DEMULCENT:
• Soothe the throat
• Reduce afferent impulse from inflamed / irritated pharyngeal mucosa.
II. EXPECTORANTS: There are two types of mechanisms
a) Secretion enhancers
b) Mucolytics

5. A) SECRETION ENHANCER
Expectorants
Increases bronchial secreation or decreases viscosity of cough
Easy removal of cough
E.g. 1.Sodium/ potassium citrate: Increases bronchial secreation or
Reduce viscosity by salt action
2.Potassium iodide: secreted by bronchial glands can irritate airways
mucosa prolong use cause iodism
3.Guaiphenesin, vasaka, tolu balsam: plant products enhance bronchial
secreation by tracheobronchial glands
4.Ammonium salts: increases bronchial secreation

6. B) MUCOLYTICS:
These agents dissolve thick mucous
Helps to relieve respiratory difficulties
By breaking disulfide bonds in mucopolysaccharides
Decreases the viscosity of secretions
Easy expulsion of mucous

7. Examples of mucolytics:
Uses of mucolytics:
1. Tracheostomy
2. Asthmatic bronchitis
3. Cystic fibrosis
Example Mechanism of action
1. Bromhexine Derivative of alkaloid vasicine(obtained from vasaka).
Depolymerization of mucopolysaccharide and makes
mucous less viscous
2. Ambroxol metabolite of bromhexine and gives same action as
bromhexine.
3.Acetylcysteine and
carbocysteine
opens disulphide bonds in the mucoproteins present in
sputum and makes it less viscid.

8. III. ANTITUSSIVES: They act by two mechanism
ANTITUSSIVES
CNS Peripherally
To raise the threshold of cough centre To reduce tussal impulse

9. Examples of antitussives:
1. OPIOIDS:
2. NON OPIOIDS:
Example Mechanism of action
a) codeine Opium alkaloid , less potent than morphine and suppress cough for about
6 hrs.
Contraindicated in asthma
b) Ethylmorphine Closely related to codeine which is methylmorphine
Respiratory depressant properties
c)Pholcodine Longer acting upto 12 hrs.
Example Mechanism of action
a)Noscapine Depresses cough but has no narcotic, analgesic or dependence
inducing properties
b)Dextromethorphan Synthetic central NMDA (N- methyl d-aspartate) receptor antagonist .It
is d- isomer has antitussive action and l- isomer has analgesic action

10. 3. ANTIHISTAMINICS:
It is a sedative and have anticholinergic action.
They have lack selectivity for cough centre.
Examples of antihistaminics
Example Mechanism of action
a) Chloramphenicol Bind toH1 receptor & block action of endogenous
histamine
b) Diphenhydramine Block action of H1 receptor
c) Promethazine H1 receptor antagonist; blocks the action of histamine

11. IV. BRONCHODILATORS :
They can induce bronchospasm or aggravate the cough.
Examples of bronchodilators:
1. Salbutamol Activates β 2 receptor in bronchial smooth muscle
Activates adenyl cyclase activity increases cAMP Smooth muscle
relaxation Bronchodilation.
2. Terbutaline Releases bronchial smooth muscle By stimulating β 2
adrenergic receptor Inhibits release of hypersensitivity mediators
Specially from mast cells.