respiratory drugs Flashcards
asthma is a complex disease characterised by what
airway inflammation
what marks the inflammatory component of asthma
airway oedema, goblet-cell hyperplasia, mucus secretion and infiltration
the newer name for COPD
RAO, recurrent airway obstruction
COPD is caused by what
an abnormal inflammatory response to an inhaled environmental insult
what are the two frequently overlapping diseases COPD can be divided into
emphysema and chronic bronchitis
sympathetic effect on the airway causes what
bronchodilation
parasympathetic effect on airway causes what
bronchoconstriction
the two receptor types expressed by airway smooth muscle cells
beta2 adrenergic and muscarinic
beta2 adrenergic receptors are activated by what
adrenaline
muscarinic receptors cause what when stimulated
bronchoconstriction
beta2 adrenergic receptors cause what when stimulated
bronchodilation
what effect does mast cell degranulation produce
bronchoconstriction and airway inflammation
what effect do cysteinyl leukotrienes induce
bronchoconstriction
types of drugs acting on the respiratory system
- bronchodilators
- resp antiinflammatory drugs
- antitussives
- mucolytics, expectorants
indications for bronchodilators
- anaphylaxis
- allergic bronchitis
- asthma
- pulmonary edema
- pneumonia
- pleural effusion
- pneumothorax
- tracheal collapse and hypoplasia
groups of bronchodilators
- sympathomimetics
- anticholinergic substances
- xanthine derivatives
sympathomimetics mechanism of action to cause bronchodilation
act on beta2 receptors - incr cAMP
two groups of sympathomimetics
- non specific
- specific/beta2 receptor agonists
non specific sympathomimetics
- adrenaline
- isoproterenol
- ephedrine
specific sympathomimetics
- salbutamol
- terbutaline
- clenbuterole
- salmeterol
adrenaline bronchodilation mechanism of action
at beta2 receptors
indications adrenaline for bronchodilation
only in life threatening situations eg anaphylaxis
which drug is isoproterenol similiar to
adrenaline
ephedrine mechanism of action
directly and indirectly
ephedrine indications
- bronchodilator
- tachyphylaxis
two types of beta2 agonists bronchodilators
- short acting
- long acting
short acting beta2 agonists duration
1-4hrs
long acting beta2 agonists duration
6-12hrs
side effects beta2 agonists
tachycardia, restlessness, tremors, decr uterine contraction
beta2 agonists contraindications
congestive heart failure
duration salbutamol per os
30mins
duration salbutamol inhalation
5mins
long acting beta2 agonists
- terbutaline
- clenbuterole
- salmeterol
terbutaline duration
6-8hrs
terbutaline selectivity
less
clenbuterole selectivity
less
clenbuterole duration
6-8hrs
clebuterole target species
less effective in companion animals, frequently used in horse
clenbuterole is prohibited in what
racing and food production (horses)
salmeterol selectivity
most selective
salmeterol duration
longest, 10mins-2hrs
how do we minimise adverse effects of adrenergic agonists
by inhalant delivery
beta1 receptor activity causes what
cardiac effects - tachycardia, arrythmias
which drugs give us beta1 receptor activity
ephedrine, isoproterenol
beta2 adrenoreceptor agonists cause what
skeletal muscle tremor
alpha adrenoceptor activity causes what
vasoconstriction and hypertension
side effects of acetylcholine antagonists
tachycardia, mydriasis, decr mucociliary clearance
acetylcholine causes paralytic ileus in which species
equine
indications for acetycholine antagonists
- asthma in fe
- RAO in eq
- organophosphate toxicosis
parasympatholytic bronchodilators
- acetylcholine antagonists
- atropine
- glycopyrrolate
- ipratropium
when should we use atropine and glycoyrrolate in eq RAO
only in life threatening situation
glycopyrollate vs atropine
longer duration, much safer
what kind of amine is atropine
tertiary
what kind of amine is ipratropium
quaternary
does ipratropium cross the blood brain barrier
no
does ipratropium affect mucociliary clearance
no
methyl xanthine derivatives bronchodilators
- caffeine
- theophylline
- theobromine
derivatives of theophylline
- aminophylline
- propentophylline
- pentoxyphylline
methyl xanthine derivatives mechanism of action
phosphodiesterase inhibitor -> cAMP level incr -> bronchodilation
pharmacokinetics of methyl xanthine derivatives
- good absorption
- enterohepatic circulation -> activated carbon
side effects of methyl xanthine derivatives
diuresis, palpatations, hyperacidity, CNS stimulation
methyl xanthine derivatives TI
small
methylxanthines indications
bronchitis, pneumonia
methyl xanthines dosage forms
iv, po, rectally
propentophyllin has a vasodilator effect in which organs
brain, muscles, kidney
therapeutic use of methyl xanthines
acute or chronic asthma thats unresponsive to beta-adrenoceptor agonists, COPD and emphysema
methyl xanthines adverse effects
arrythmias, nervousness, vomiting and GI bleeding
types of respiratory anti-inflammatories
- inhalational glucocorticoids
- chromones
- leukotriene antagonists
resp anti-inflammatories indication
asthma, RAO
inhalational GCs mechanism of action
inhibition of the expresssion of several genes -> decr cytokine production
what do inhalational GCs do to mucus production
decr
what do inhalational GCs do to diameter
increasing
is it possible to systemically apply inhalational GCs
yes, but several side effects
definition of an antitussive
any medicine used to suppress or relieve coughing
whats a mucolytic
destroying or dissolving mucus
whats an expectorant
drugs that loosen and clear mucus and phlegm from the resp tract
antitussives mechanism of action
they suppress the cough centre
types of peripheral antitussives
- mucolytics, expectorants
- bronchodilators
- coating substances
- local anaesthetics
types of central antitussives
morphine derivatives
codeine vs morphine
- better bioaval
- 10 times lower analgesic potency
- similiar antitussive
why shouldnt we use codeine in cats
excitation
possible rare side effects of codeine
convulsions, sedation, constipation
can dihydrocodeine be used in cats
no
is butorphanol safe for use in cats
yes
butorphanol features
most effective, but sedation
which receptor does dextrometorphan act on
sigma receptor
is dexmetorphan addictive
no
is dexmetorphan analgesic
no
dextrometorphan, can it be used in cats
yes
tramadol can it be used in cats
yes
mucolytics and expectorants indications
bronchitis, bronchopneumonia, tracheitis, rhinitis, sinusitis, RAO as adjunctive therapy
mucolytics and expectorants mechanism of action
dissolution of dense, sticky mucus inside the resp tract -> productive coughing
list of mucolytics
- N acetylcysteine
- carbocystein
N acetylcysteine mechanism of action
breaking up disulphide bonds in mucoproteins -> dissolution of viscious mucus
N acetylcysteine administration route
per os, inhalation
for which type of toxicosis is N acetylcysteine an antidote
paracetamol toxicosis
carbocysteine vs N acetylcysteine
similiar action, oral absorption a little better
where do expectorants act directly
mucus membranes of airways
where do expectorants act indirectly
stimulating gastric mucus membranes
list of expectorants
- bromhexin
- guaifenesin
bromihexin three actions
- breaking up mucopolysaccharides, dissolving mucus
- -incr secretion of serous glands
- enhancing ciliary movement
what does bromhexin do to the permeation of Igs and ABs
enhances it
what happens to iGa and IGg levels after bromhexin admin
increased
bromhexin indications
rhinitis, sinusitis, tracheobronchitis
ambroxol what is it
metabolite of bromhexin
in which species can we apply dembrexine
equine
can guafenesin be combined with other antitussives
yes
guafenesin mechanism of action
does not change amount of mucus secretion-> enhances ciliary movement