antitussive drugs drugs pharmacology veterinary sumreen

1. SUMREEN KOUR
MVSc Scholar
Vety Medicine

2.  Agents used to relieve or
suppress coughing.
 Benificial in suppressing cough &
in decreasing morbidity in
respiratory disease.
 Indicated when cough is
painful,unproductive,distressing,
exhausting/exacebrate lung
damage.

3. PATHOPHYSIOLOGY
OF COUGH

4. Cough stimulus:pharynx
Larynx
Tracheobronchial tree
Cough centre located in medulla oblongata
Impulse(afferent
nerves): vagus
Glossopharyngeal
nerve
Effernet pathway
supplies nerve : abdomen
thoracic muscles
diaphragmic muscles
Forceful expulsion of air from lungs

5. COUGH
Duration
Acute
Chronic
Subacute
Dry/Produtive
Dry Productive

6. Peripherally
acting/locally
acting :
• Demulscents
• Mucosal
anaesthetics
• Bronchodilators
• Expectorants
• Miscellaneous
Centrally acting
• Opioid/narcotics
• Non-opioid/non –
narcoptics.

7.  Includes: honey
syrup
glycerine
liquorice
 They coat,protect & soothe throat directly &
promote salivation
reduce afferent
Impulse.
 Provide symptomatic relief in dry cough.

8.  BENZONATATE:
 Long chain polyglycol derivative local
anaesthetic.
 Related to procaine & tetracaine.
 Reduce coughing –
bronchitis,emphysema,influenza,pneumonia.
 Half life:3-8hrs.

9.  Act as local
anaesthetic.
 sensitivity to stretch
receptors in lower
airways & lungs
 Reduces drive to
cough.

10.  Drowsiness.
 Numbness of mouth & throat.
 Dysphagia.
 Allergic reactions.

11.  Drugs which causes an increase in calibre of
bronchus & bronchial tube.
 Used when there is:
- bronchial narrowing
- where improved alveolar ventillation
is required.
 Improve effectiveness of cough in clearing
secretions.
 Ephedrine.
 Theophylline.
 Isoprenaline.

12.  Mixed acting non-catecholamine which
stimulates alpha & beta receptors.
 Develop mild bronchodilation.
 Produces decongestion in bronchi which helps
to reduce mucosal swelling.

13.  No selective beta1 & beta2 adrenoceptor
agonist.
 Can be used parentrally.
 Marked brochodilation: 1-2hrs.

14.  Expectorants are agents which increase
volume or fluidity of secretion in respiratory
tract & fascilitate their removal by ciliary
action.
 Bromohexine
 Water aerosols

15.  Synthetic derivative of alkaloid vasicine
(adhatoda vasica).
 Useful if mucus plug present.
 Administered both oral & parentral routes.
 Used:
 Bronchitis
 Bronchopneumonia
 Chronic cough

16.  Mucus clearance.
 Fascilitate expectoration
 Allow animal to breathe freely.
Depolymerises mucopolysacchrides directly & liberate
lysosomal enzyme causing breakdown of network of fibres of
tenacious sputum
Increases Ig level in airways secretions enhancing membrane
permeability.
Active metabolite –stimulates & releases surfactant by type 2
pneumocytes –act as anti glue factor

17.  Used ocassionally to liquefy hyperviscous
mucus in repiratory tract.
 Aerosol/mist therapy only delivers few mm
of water to smaller pulmonary airways &
lungs.

18.  Dropizine
 Levodropropizine

19.  Opioid antitussive:
 Codeine
 Hydrocodone
 Butorphanol
 Hydromorphone.
 Non opioid antitussive:
 Dextromethorphan
 Noscapine
 phoicodine

20.  Potent inhibitors of medullary cough centre
at sub-analgesic dose -antitussive.
 Assoiated with:
 Sedation
 Constipation
 Depression of respiratory centre

21.  Opiate alkaloid
 Available both as base &
 phosphate & sulphate salts.
 ACTION:
 Causes direct suppression cough centre in
medulla.
 Action can be blocked by naloxane.
 Onset of action after oral-30min.

22.  Conversion of codiene to morphine occurs
inn liver & is catalysed by cytochrome
P450enzyme CYP2D6.
 Binds to M opioid receptors & exert effect.
 SIDE EFFECT:
 Anorexia
 Vomition
 Constipation
 Biliary & pancreatic duct spasm.
 Depression.

23.  Use with CNS depressants may increase CNS
/respiratory depressant action.
 Anticholinergic drug used with codiene may
increase chances of constipation.
 DOSE:
 Dogs:0,5-2 mg/kg PO

24.  Is synthetic opioid partial agonist
 Is potent analgesic and antitussive agent
 After oral administration it is completely
absorbed but undergoes a significant first
pass metabolism after oral administration
 DOSE –
DOG – 0.1-0.25 mg/kg bwt.

25.  Have been developed to increase safety of
centrally acting antitussive drugs.
 DEXTROMETHORPHAN:
 It’s a d-isomer of codiene aanalogue levorphanol.
 Occurs as odourless to whit yellow crystalline
powder.

26.  Mechanism of action:
 It acts as uncompetitive NMDA receptor
agonist & serotonin & norepinephrine
transporter blocker at different
concentrations.
 Pharmacokinetics:
 Absorbed by gastrointestinal tract
 enters blood stream & cross BBB.
 In liver it is metabolised by Cyt P450 enzyme
metabolite dextrorphan

27.  not used in allergic reactions
DRUG INTERACTIONS
Should not be administered along with MAOI or serotonin uptake
inhibitor due to potential for serotonin syndrome – life threatening
DOSE – 1-2 mg/kg bwt

28. THANK YOU