Respiratory pharmacology - other Flashcards
Apart from drugs affecting bronchiole diameter, what are 6 other broad categories of respiratory drugs?
Antitussives Surfactants Expectorants Drugs affecting respiratory centre Decongestants Mucolytics
Coughing is a defence mechanism. Why are anti-tussive drugs sometimes required?
Coughing becomes non-productive (damaging) and exhausts animal
Anti-tussives can be direct or indirect. Briefly explain how these 2 types of drug reduce coughing
Direct antitussives - suppress cough centre in medulla oblongata
Indirect antitussives - reduce stimuli to cough
Direct antitussives suppress the cough centre in the medulla oblongata. Give 2 examples of a direct antitussive
Codeine
Butorphanol
(Given in lower doses than for analgesia!)
What are the side effects of direct anti-tussives?
Suppress other CNS functions, cause:
Constipation
Sedation
Cardiovascular and respiratory depression
What type of agonist is butorphanol? What are 2 advantages of it compared to codeine? Where is it metabolised? What should be considered when giving butorphanol to pregnant animals?
Partial opioid agonist
100X more potent than codeine and less respiratory depression
Metabolised in liver
Crosses placenta
What type of ‘drug’ can be given for neonatal respiratory distress syndrome? Where is this drug extracted from and how is it applied?
Surfactant
From bovine lung
Topically applied
What do mucolytics do?
Decrease viscosity of bronchial secretions
Improve mucociliary clearance
What are examples of non-pharmacological mucolytics?
Steam (increases mucous water content to make it easier to come up)
Physiotherapy
Give 2 examples of pharmacological mucolytics
Bromhexine HCl
N-acetylcysteine
How does bromhexane HCl act as a mucolytic? When is it not effective? How is it administered?
Enhances hydrolysis of mucopolysaccharides
If infection or inflammation present (protein in there)
Oral/parenteral administration
How does N-acetylcysteine act as a mucolytic? Is it effective during infection/inflammation? How is it administered?
What are its side effects?
Break disulphide bonds between mucus molecules
Yes - effective during infection
Topical administration
Bronchoconstriction and airway irritation
What are expectorants and how do they work?
Drugs that bring up mucus
Irritate gastric mucosa and increase vagal tone which increases bronchial secretions
Give an example of an expectorant drug
Potassium iodide
What is nasal congestion? How do decongestants work?
Blockage of nasal passages due to nasal mucus and inflammed mucosa
Reduce thickness of nasal mucosa
What are two examples of decongestants?
Antihistamines (not effective in animals)
Sympathomimetics
How do sympathomimetics allow decongestion?
Cause vasoconstriction and reduced ECF in nasal mucosa
How are sympathomimetic decongestants administered? What is their disadvantage
Oral/topical administration e.g. nasal sprays
Difficult to use in animals
Give examples of drug categories that suppress the respiratory centre
Sedatives
Opioid analgesics
Anaesthetics
Antiepileptics
Give an example of a drug that stimulates the respiratory centre. In what animals is this drug usually used?
Doxapram
Neonates
What effects does doxapram cause, apart from stimulating the respiratory centre?
Increased chemoreceptor sensitivity
Increased RR and tidal volume
Increased adrenaline release
What effect can doxapram have when being used in conjunction with opioids? (In neonates or the foetus preparturition!)
Can cause seizures
How is doxapram administered?
Topical or parenteral administration
