Dr. Jibachha Sah,M.V.Sc( Veterinary pharmacology, TU,Nepal),posted lecturer notes on AUTONOMIC AND SYSTEMIC PHARMACOLOGY for B.V.Sc & A.H. 6 th semester veterinary students of College of veterinary science,Nepal Polytechnique Institute, Bharatpur, Bhojard, Chitwan, Nepal.I hope this lecture notes may be beneficial for other Nepalese veterinary students. Please send your comment and suggestion .Email:jibachhashah@gmail.com,moble,00977-9845024121

1. Expectorants and antitussives
Dr.Jibachha Sah
M.V.Sc (Pharmacology)
College of veterinary science, NPI,
Bhojard,Chitwan

2. Expectorant: A medication that helps bring up mucus and
other material from the lungs, bronchi, and trachea.

5. Mechanism of action
Expectorants – induce coughing
Mucolytics – thin the mucus.
Mucokinetics – enables easier transportation of cough
Mucoregulators – suppress underlying mechanisms of mucus hypersecretion

6. ● Cough receptors (chemo-and-mechano receptors ) lie in mucosa of the bronchial tree
from the nose to the distal bronchi.
● The impulses from these receptors are transmitted through the vagus and
glossopharyngeal nerves to the cough center in the medulla.
Mechanism of cough production
The cough receptors lie in the mucosa of the bronchial tree. Afferent impulses passes to
the medulla. Then an autonomic sequence of events is triggered by medulla causing
certain effects.

7. Two Basic Types of Cough
● Productive cough Congested, removes excessive secretions
● Nonproductive cough Dry cough
Classification of cough
● Acute:- less than 3 weeks.
● Sub-Acute:- between 3-8 weeks.
● Chronic:- longer than 8 weeks. 9

8. Expectorants and mucolytic agents are different types of medication, yet both are intended
to promote drainage of mucus from the lungs.
An expectorant increases bronchial secretions and mucolytics help loosen thick
bronchial secretions.
Different between Expectorants and mucolytic
One expectorant, guaifenesin, is commonly available in many cough syrups and also as
long release tablets.

9. Mucoactive drugs
Many mucoactive drugs are available, including sodium citrate or potassium
citrate, potassium iodide, guaifenesin, tolu balsam, vasaka, and ammonium
chloride.
Mucolytic drugs available
include acetylcysteine, ambroxol, bromhexine, carbocisteine, erdosteine, mecys
teine,[4] and dornase alfa.

10. Antitussives
Antitussives are medicines that suppress coughing, also known as cough suppressants.
CLASSIFICATION
1) CENTRALLY ACTING ANTITUSSIVE:-
Narcotic antitussive:- Codeine Hydrocodone Oxycodone
Narcotic antitussive:- antitussive:- Dextromethorphan Noscapine Propoxyphene
2) PERIPHERALLY ACTING ANTITUSSIVE:-
Mucosal anaesthetics:- Benzonatate Chlophedianol
Hydrating agents:- Steam Aerosols
Miscellaneous:- Bromhexine

11. ANTITUSSIVE MOA
●OPIOIDS:- Suppress the cough reflex by acting on the cough center in the medulla.
● NON-OPIODS:- Suppress the cough reflex by numbing the stretch receptors in the
respiratory tract and preventing the cough reflex from being stimulated

12. ANTITUSSIVE INDICATION
●Used to stop the cough reflex when the cough is non-productive i.e dry cough
ANTITUSSIVE CONTRAINDICATIONS
● Asthma
● COPD (Chronic obstructive pulmonary disease)
● Hypersensitivity
● Head injury
● Pregnancy

13. The cough reflex

14. Drug Dosage
Codeine Dogs: 1–2 mg/kg, PO, bid-qid
Hydrocodone Dogs: 0.25 mg/kg, PO, bid-qid
Butorphanol
Dogs: 0.055–0.11 mg/kg, SC, bid-qid,
or 0.55–1.1 mg/kg, PO, bid-qid
Cats: 0.1–0.4 mg/kg, SC, bid-qid
Antitussive Drugs

25. Doses of Drugs Used To Treat Disorders of the Respiratory Tract