Pharmacognosy: Antitussive Drugs.

Antitussive Drugs.

A cough is a protective reflex stimulated by the body to remove the unwanted particles from the respiratory tract. However, a cough can be pathological and may disturb the daily routine work of individual and hence when it becomes disturbing has to be stopped.

Antitussives the name is derived from,

Anti means "Aganisnt"

"Tussis" means "a cough", and hence anticough.

Antitussives can be defined as the drugs which ae used in treatment of cough.

  • A cough can be categorized into a dry cough or a wet cough.

  • A dry cough is also called as "Smokers Cough" and is not associated with mucus and hence called as "Dry", it produces a characteristic sound while coughing.

  • A dry cough responds well to centrally acting cough suppressants.

  • A wet cough is always associated with mucus and produces a wheezing sound during coughing, its is also called as "a productive cough."

  • A wet cough usually responds well to the expectorants.

Classification of Antitussive Drugs:

  • Based on Mechanism of Action.

  1. Centrally acting cough center depressants:

  • These drugs depress the cough center located in CNS.

  • They are potent drugs usually associated with sedation.

  • They are useful in the treatment of a dry cough.

  • e.g. Codeine and Noscapine from Opium.

              2. Demulcents:

  • These are usually viscous in nature and act by soothing the irritating membrane of the pharynx.

  • These are particularly useful in the treatment of "sore throat".

  • e.g. Honey.

             3. Expectorants:

  • These drugs make thick mucus flowable and hence helps to expel it out during coughing.

  • e.g Ipecac, Vasaka, Balsam of Tolu etc.

            4. Mucolytics:

  • These drugs breakdown "disulfide" linkage in the mucus making it free to flow.

  • e.g. Vasaka.

A) Vasaka:

  • Synonym:

  • Adulsa, Vasaka Leaves.


  • Biological Source: 

  • Vasaka consists of dried as well as fresh leaves of the plant known as Adathoda vasika belonging to the family Acanthaceae.


  • Physical characteristics:

  • Color: Green to dark green.Antitussive drugs

  • Odor: Characteristic.

  • Taste: Bitter.

  • Size: 10 to 30 cm X 4 to 10 cm.

  • Shape: Lanceolate, entire margin, symmetrical base.

  • Chemical Properties:

  • Vasaka contains active chemical constituents as "Quinazoline Alkaloids."

  • The chief active constituents of the drug are "Vasicine and Vasicinone."

  • Vasicine has a tendency to get autoxidized to vasicinone.

  •  Vasaka also contains less active chemical constituents as "Vasakin, Adathodic acid and Vol. oils."

  • The inert chemical constituents of the drug are "Starch, calcium oxalate crystals, proteins etc."


  • Uses:

  • Antitussive: As an Expectorant and Mucolytic.

  • Bronchodilator.

  • As an oxytocic.


  • Adulterants:

  • 1) Alianthus excelsa. 2)Adathoda badonine.

2) Tulsi:

  • Synonym: Tulas, Holy Basil, Sacred Basil.


  • Biological Source:

  • Tulsi consists of dried as well as fresh entire herb known as "Ocimum sanctum" belonging to family "Labiatae."


  • Physical Properties:

  • Color: Green to dark green.Tulsi

  • Odor: Characteristic aromatic.

  • Taste: Pungent characteristic.

  • Size: leaves are 3cmto 5cm long.

  • Shape: Leaves are petiolate and ovate in shape.




  • Chemical Properties:

  • Tulsi contains "Volatile Oils" as active chemical constituents.

  • Active constituents from volatile oil of Tulasi are oleanolic acid, ursolic acid,rosmarinic acid, eugenol, carvacrol, linalool, β-caryophyllene (about 8%), β-elemene (c.11.0%), and germacrene D (about 2%).

  • It also contains thymol and safrole.


  • Uses:

  • Tulsi is useful as an expectorant antitussive.

  • It is reported to have Antibacterial and Antiviral actions.

  • Volatile oil of Tulsi is insect repellent.

  • Tulsi is one of the major ingredients in many Ayurvedic formulations.


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