Week 11- Drugs for the airway 1 and 2 Flashcards
what is acute infectious tracheobronchitis
- common urt disease
- caused by multiple infectious agents
how does acute infectious tracheobronchitis present
- acute onset hacking cough
- often history of recent exposure to other dog
- clinically bright, active, eating
- lung auscultation normal or sightly harsh upper airway sounds
- cough may be induced on tracheal pinch
How might you treat acute infectious tracheobronchitis?
- Restrict exercise
- avoid access to airborne pollutants or irritants
- give wet food
What vaccination is given for acute infectious tracheobronchitis?
- live strain of canine parainfluenza and bordatella
- Vaccinated animals can spread B.bronchisepta vaccine strain for a few weeks and the canine parainfluenza vaccine strain for a few days after vaccination
What is an antitussive drug?
Drugs that suppress coughing
* Demulcents
* Centrally acting opiates
What kinds of drugs might you give for a respiratory disease?
- Antitussive drugs
- Decongestants/ mucolytics
- Bronchodilators
- Drugs to reduce airway inflammation
What is the main function of an antiussive/ when are they used?
- they decrease the frequency of coughing
- treat painful non-productive coughing
- or when coughing may cause further injury
What is the function of a demulcent?
- such as honey or syrup
- coat and soothe inflamed tissues
- provide brief periods of relief from mild stimulus
what supresses the medullary cough centre in low doses
centrally acting opiates
What do mucolytics stimulate?
- Increase in fluid secretion by the mucus glands of the resp tract and break down the network of acid glycoprotein fibres found in mucoid sputum
How does bronchodilation occur?
Activation of muscarinic
receptors causes contraction
of airway smooth muscle ->
bronchoconstriction
So we want to block with
a muscarininc receptor
antagonist
What is ipatropium bromide?
- long-acting
- given once a day
- via inhalation
- used for RAO in horses
What is salbutamol used for?
predominantly stimulates B2 receptors causing an increase in cyclic AMP
What is clenbuterol used for?
- highly selective for the beta 2 adrenoceptor
- provides intense bronchodilating properties
- minimal effect on the cardiovascular system
What animals is clenbutarol licensed for treatment in?
Licensed in horses for treatment of respiratory disease where the airway obstruction is due to bronchospasm and/ or accumulation of mucus
What is theophylline?
Similiar in structure to caffeine and theobromine
* relaxes smooth muscle, relieves bronchospasm
What is the mechanism of action of theophylline?
Mechanisms of action are thought to include inhibition of
phosphodiesterase enzyme, alteration of intra-cellular calcium,
catecholamine release and adenosine and prostaglandin antagonism
* Also dilates coronary arteries and increases the strength of
contraction of the myocardium. Acts on kidney to induce diuresis and
is a potent stimulant of the CNS
What is the function of mast cell stabilisers?
Sodium cromoglycate inhibits mast cell degranulation of histamine on antigen challenge and may also have membrane stabilising properties
What are the main effects of glucocorticoids?
exogenous glucocorticoids (e.g. prednisolone, dexamethasone,
beclomethasone H, fluticasone H) inhibit the transcription of genes
responsible for the production of mediators involved in airway inflammation
(cytokines, chemokines, adhesion molecules)
* Manage exacerbations and establish control with prednisolone /
dexamethasone
* Maintain patients on inhaled beclomethasone H / fluticasone H
* Prolonged release steroid, methylprednisolone, useful for cats with asthma
What is the function of B-lactam antibiotics?
inhibit bacterial growth by
interfering with the transpeptidation of bacterial wall synthesis - bactericidal
What is amoxicllin?
Broad spectrum penicillin effective against gram +ve bacteria and gram -ve bacteria
What is clavulanate potassium?
irreversible inhibitor bacterial B-lactamases and prevents hydrolysis of amoxicllin
What is the function of tetracyclines?
they inhibit protein synthesis in susceptible bacteria (bacteriostatic)
good lung penetration
What is trimethoprim?
folate antagonist- bacteriostatic
What is trimethoprim often combined with?
sulphonamides
What is the mechanism of action for antifungals?
- highly selective binding for fungal cytochrome P-450
isoenzymes. Inhibit the synthesis of ergosterol, which is essential component
of cell membranes for fungi. Also affect membrane-bound enzyme function
and membrane permeability, resulting in structural degeneration of the fungus
