Respiratory (year 2) Flashcards
what can drugs stimulate to effect bronchial diameter?
sympathetic nervous system
parasympathetic nervous system
non-adrenergic non-cholinergic neurotransmission
irritant receptors
what effects can the autonomic nervous system have on bronchial diameter?
sympathetic - bronchodilation
parasympathetic - bronchoconstriction
what receptors mediate bronchodilation via the sympathetic nervous system?
beta2 adrenoreceptors
what receptors mediate bronchoconstriction via the parasympathetic nervous system?
muscarinic receptors
the parasympathetic system causes bronchoconstriction and what other effect on the airways?
increases mucus production
the sympathetic system causes bronchodilation and what other effects on the airways?
increases mucociliary clearance
reduce inflammatory mediator release
Why must treatment be highly selective to the receptor type found in the airways?
minimise the side effects
what nervous system do adrenoreceptor agonists effect?
sympathetic nervous system
what are the neurotransmitters for adrenoreceptor agonists?
adrenaline and noradrenaline
name the beta2 agonists used to cause bronchodilation
terbutaline, salbutamol, albuterol, clenbuterol
what are the main effects of alpha adrenoreceptors on the body?
vasoconstriction, intestinal sphincter contraction, pupil dilation
what are the main effects of beta adrenoreceptors on the body?
vasodilation, increased HR, bladder relaxation, metabolic stimulation
how is turbutaline administered?
parenteral or oral
how is albuterol administered?
oral or topical
how is clenbuterol administered?
oral
what are the adverse effects of beta2 agonists?
BP abnormalities, tachycardia, hypokalaemia, seizures
what drug group is used as a parasympathetic antagonist to cause bronchodilation?
anticholinergics
what receptors do anticholinergics effect in the respiratory tract?
muscarinic
what effects other than bronchodilation do anticholinergics have on the respiratory tract?
reduce bronchial irritant response
pulmonary vasoconstriction
reduce mucus production
what are the side effects of anticholinergics?
tachycardia, dry MM, reduced gut motility, hypertension, mydriasis
what is the only anticholinergic used in veterinary respiratory disease?
ipratropium
how is ipratropium administered?
inhalation
what is the name of the drugs that enhance the action of the parasympathetic nervous system?
cholinergics
what effect do cholinergics have on the respiratory system?
bronchoconstriction
increased mucus secretion
what is a group of drugs that will act directly on smooth muscle of the respiratory system?
methylxanthines
what is the mode of action of methylxanthines?
phosphodiesterase inhibitors so block cAMP degredation
adenosine antagonists which further increases cAMP
what are the effects of methylxanthines?
bronchodilation inhibit inflammatory mediator release increase catecholamine release increase mucociliary clearance increase CNS sensitivity to carbon dioxide
what are the adverse effects of methylxanthines?
tachycardia, excitability, seizures, GI motility effected
give an example of a methylxanthine used for respiratory disease
theophylline
how is theophylline administered?
oral
why are CNS side effects associated with theophylline?
the drug can penetrate the blood:brain barrier
where is theophylline metabolised and excreted?
metabolised in liver and excreted by kidney
what is the name for drugs that stop coughing?
anti-tussives
when would antitussives be used?
if the animal is becoming exhausted or the cough is non-productive
where do direct antitussives effect?
they suppress the cough centre in the medulla oblongata
what effects do indirect antitussives have?
reduce inflammation
reduce bronchoconstriction
reduce mucus accumulation
what drugs are used as direct antitussives?
opioids
what is the mode of action of opioids when acting as antitussives?
agonist of mu receptors in the medulla reducing the response to irritant stimuli
how are opioids administered?
oral or parenteral
what are the side effects of opioids?
suppression of CNS function - sedation, CV depression, constipation, respiratory suppression
give two examples of opioids used as antitussives
codeine and butorphanol
where is butorphanol metabolised?
liver
what are surfactants?
lipid molecules extracted from bovine lungs
when are surfactants used?
usually during neonatal respiratory distress syndrome
what is the role of mucolytics?
decrease the viscosity of bronchial secretions
what are some non-pharmaceutical methods of decrease bronchial secretion viscosity?
nebuliser sterile saline
physiotherpay
name two mucolytics
bromhexine HCl
N-acetylcysteine
what is the mode of action of bromhexine HCl?
enhances hydrolysis of mucopolysaccharides
what is the mode of action of N-acetylcysteine?
breaking disulphide bonds between mucus molecules
when is bromhexine HCl not effective?
in the presence of infection or inflammation as it doesn’t effect proteins from bacteria or neutrophils
how is bromhexine HCl administered?
oral or parenteral
what are the side effects of N-acetylcysteine?
bronchoconstriction and airway irritation
what do expectorants do?
increase fluidity of bronchial secretions to aid clearance (not commonly used in veterinary)
how do expectorants worK?
irritate gastric mucosa leading to increased vagal tone and hence increased bronchial secretions
what is the function of decongestants?
reduce the thickness of nasal mucosa to enable easier passage of air
what drugs are used as decongestants?
sympathomimetics
how are sympathomimetics administered?
oral or topical
what are the effects of sympathomimetics on the respiratory system?
vasoconstriction and reduced ECF in nasal mucosa
name a sympathomimetic
ephedrine
what drugs can be used to effect the respiratory centre?
sedatives, opioids, anaesthtics, antiepileptics
name a respiratory stimulant
doxapram
what is the mode of action of doxapram?
increases chemoreceptor sensitivity to increase RR and tidal volume
how is doxapram administered?
topical or parenteral
what are the side effects of doxapram?
cardiac arrhythmias
