Respiratory pharm and therapeutics Flashcards
name 3 diseases which require bronchodilators and the species they affect
RAO - horses
asthma - cats
chronic bronchitis - dogs
name a short acting B adrenergic agonist
adrenaline
name 3 longer acting B adrenergic agonists
terbutaline, salbutamol, clenbuterol
what is the mechanisms of action of bronchodilators?
bronchial sm innervated by B2 receptors. cause increase in cAMP so relaxation of sm therefore bronchodilation
what is the problem with using adrenaline and how is it administered?
non-specific so acts on heart and bv’s. used for anaphylaxis as unsuitable for longterm used
IV/ IM
what formulations is adrenaline in? and how do you calculate mg/ml?
1:1000 (0.1%) and 1:10000 (0.01%)
to get mg/ml x % by 10
what is the benefit of using salbutamol, clenbuterol or terbutaline?
the are specific so only affect bronchial sm (B2) and not heart. longer acting so can be used long term.
available for inhalation
describe the properties of terbutaline
often used in cats with asthma. oral/ inject in emergency
lasts 6-8h
describe the properties of salbutamol
= ventolin. used in inhalers
describe the properties of clenbuterol
= partial agonist so less effective. licensed for use in horses
what are adverse effects of B agonists
stim symp system - tachycardia, vasoconstriction (B1 mainly), tremors, and tolerance so use in phases
what is cromolyn used for?
stabilises mast cells so inhibits release of histamine leading to reduced bronchoconstriction. Must be given before allergen exposure - used in horses with RAO
Give an example of a methylxanthine and explain its properties
theophylline. relaxes sm and poss anti-inflammatory. licensed in dogs, given as extended release capsules (dose less frequently) orally, highly bioavailable. commonly used for CB and asthma (SE in horses)
SE conc dependent - V, cardiac (symp), CNS poss seizures.
SE = V, cardiac, CNS
what are anticholinergic drugs used for?
muscarinic (parasymp) antagonists. used in horses but not dogs and cats.
give 3 examples of anti-cholinergics and describre SE
hyoscine - mainly used for colic but also emergency bronchodilator IV
atropine - emergency IV, ileus, tachycardia and CNS toxicity
ipratroprium - aerosol, less SE
describe the cough reflex
irritation in bronchi/ trachea, sensory nerves, medulla oblongata, cough
What are B agonists antitussive?
because they cause bronchodilation
what drug type are often used for antitussives?
opioids
name and explain the properties of an opioid used as an antitussive
butorphanol. kappa agonist. oral/ inject. poor oral bioavailability so need higher doses.
(also others - codeine, morphine = mu agonists)
give and example of a non-opiate used as an antitussive
dextromethorphan. may or may not be effective but available over the counter. be aware of other toxic medicines e.g. paracetamol
why might eucalyptus oil be used?
expectorant - increases tract secretions
what is guaifenesin used for?
anaesthesia, muscle relaxant + increase secretions
Give an example of a mucolytic drug and explain its properties
bromhexine - stimulates increase in secretion of fluids, breaks down mucoid sputum, increases mucociliary clearance.
may increase antibiotic availability in pigs and cattle
available as injection (PCo) and powder (PCoCD)
what is acetylcysteine used for?
mucolytic - rarely used in vet med
antidote for paracetamol poisoning in cats
what is nebulisation?
creation of small droplets of a drug that can be delivered to the airways. less systemic absorption so useful for drugs e.g. glucocorticoids
e.g. salbutamol
how would you treat a horse with RAO?
management changes, bronchodilators, corticosteroids (laminitis), mucolytics
how would you treat dogs with CB?
management, bronchodilators (oral/ inhaled), glucocorticoids, antibiotics if infections, not really muco/ antitussive as contra-indicated
how would you treat cats with asthma
rule out other causes (smoking, scented candles, air fresheners), management, glucocorticoids (oral/ inhaled), bronchodilators
name a glucocorticoid used in an inhaled form
fluticasone
