Pharmacology Flashcards
what is the role of the parasympathetic system in the regulation of airways
stimulation of postglanglionic CHOLINERGIC fibres cause:
1. ASM contraction 2. increased mucus secretions
stimulation of postglanglionic NON-CHOLINERGIC fibres cause:
1. ASM relaxation
what is ASM contraction mediated by
M3 muscarininc ACh receptors
what is mucus secretion mediated by
M3 muscarininc ACh receptors
what is ASM relaxation (via NON-cholinergic fibres) mediated by
NO and vasoactive intestinal peptide
what is the role of the sympathetic system in the regulation of airways
THERE IS NO INNERVATION OF ASM
stimulation of submucosal glands and smooth muscle blood vessels causes:
- ASM relaxation
- decreased mucus secretions
- increased mucocilliary clearance
- vascular smooth muscle contraction
what is bronchial smooth muscle relaxation mediated by (in sympathetic stimulation)
cholinergic release of adrenal from the adrenal glands acting upon the B2-adrenoceptors
what is decreased mucus secretion mediated by
B2-adrenoceptors
what is increased mucocilliary clearance mediated by
B2-adrenoceptors
what is vascular smooth muscle contraction mediated by
A1-adrenoceptors
what is asthma
recurrent and reversible obstruction to the airways in response to substances
describe the pathological changes in the airways that occurs in chronic/poorly controlled asthma
- increased smooth muscle mass
- accumulation of interstitial fluid (oedema)
- increased secretion of mucus
- epithelial damage
- sub-epithelial fibrosis
what does epithelial damage result in
exposure of sensory nerve endings causing increased sensitivity to bronchocontstrictor influences
what is hyper-sensitivity
decreased tolerance to bronchoconstriction
what is hyper-activity
increased response to bronchoconstriction
what is the reaction of a non-atopic individual to an antigen (TH____ + what immune cells)
low level TH1 response
cell mediated immune response involving IgG and macrophages
what is the reaction of an atopic individual to an antigen (TH____ + what immune cells)
strong TH2 response
antibody mediated immune response involving IgE
what are the 2 phases of an asthma attack
- immediate
2. delayed
describe the immediate phase of an asthma attack
eliciting agent is recognised and processed
mast cells and mononuclear cells release histamine etc. causing bronchospasm and early inflammation
describe the delayed phase of an asthma attack
infiltration of cytokine releasing TH2 cleaned monocytes which activate inflammatory cells (especially eosinophils)
mediators and eosinophilic proteins are released causing epithelial damage, airway inflammation, hyper-responsiveness, bronchospasm, wheezing, mucus over secretion, cough
what do TH0 cells mature to
TH1 and TH2
prefer to mature to TH2
what do TH2 cells do
activate B cells in 2 ways:
- by binding
- via IL-4 production
activate Eosinophils in response to IL-5
release IL-4 and IL-13 which causes mast cells to express IgE receptors
what do B cells mature to
plasma cells
what do plasma cells secrete
IgE
what cytokines does TH2 release
IL-4
IL-5
IL-13
what does IL-4 do
activates B cells and causes mast cells to express IgE receptors
what does IL-5 do
activated eosinophils
what does IL-13 do
causes mast cells to express IgE receptors
what are the 2 pharmacological method of asthma
relievers (bronchodilators)
controllers/preventers
Give examples of relievers (bronchodilators)
SABA
LABA
CystLt 1 receptor antagonist
methylxanthines
what is a SAMA
short acting B2-adrenoceptor agonist
what is a LABA
long acting B2-adrenoceptor agonist
give examples of controllers/preventers
inhaled corticosteroids (ICS)
cromoglicate
humanised monoclonal IgE antibodies
methylxanthines
describe the mechanism of action of LABA and SABA
bind to B2-adrenoceptor causing smooth muscle relaxtion
give examples of SABA
salbutamol, albuterol
give examples of LABA
salmeterol, formeterol
describe the mechanism of action of CystLt 1 receptor antagonist
act COMPETITIVELY at the CystLt 1 receptor
give examples of CystLt 1 receptor antagonist
montelukast, zafirlukast
describe the mechanism of action of methylxanthines
no one knows
give examples of methylxanthines
theophylline, aminophylline
describe the mechanism of action of cromones
no one knows
may be mast cell stabilisers
give an example of cromone
sodium cromoglicate
describe the mechanism of action of monoclonal IgE antibodies
binds to IgE via Fc to prevent attachment to FC receptors to suppress mast cell response to allergens
give an example of humanised monoclonal IgE antibodies
omalizumab
how are cromones used
infrequently used PROPHYLACTICALLY in kids
describe the mechanism of action of Glucocorticoids
suppress inflammation:
prevent it and resolve established inflammation
give examples of ICS
beclometasone, budesonide
give example of ORAL steroids
prednisolone
common side effects of ICS
dysphonia (hoarse/weak voice)
thrush (candidiasis)
common side effects of LABAs/SABAs
fine tremor (common) tachycardia, cardiac dysrhymia, hypokalaemia
how should a LABA be administered
CO-ADMINISTERED with a Glucocorticoid
or as an add on therapy
can LABA be prescribed on its own
NO
can SABA be prescribed on its own
yes
how are CystLt 1 receptor antagonist administered
orally
how are methlyxamines administered
orally
side effects of methlyxamines
MANY, very narrow therapeutic window
nausea, vomiting, abdominal discomfort, headache (common)
dysrhymia, seizures, hypotension (rarer)
describe the MOLECULAR mechanism of action of Glucocorticoids
enters cells via diffusion
series of interactions results in the transcription of specific genes to activate OR repress mRNA levels and the rate of synthesis of mediator proteins
what causes the anti-inflammatory actions of Glucocorticoids
increases the transcription of genes encoding anti-inflammatory proteins
decreases the ranscription of genes encoding inflammatory proteins
decrease formation of TH2 cytokine
prevents production of IgE antibodies
prevents allergen-induced influx of eosinophils into lungs
reduce the number of cells and decrease Fc expression
how is omalizumab administered
IV
why is synthetic derivates of cortisol used instead of the real thing
they contain NO traces of unwanted mineralocorticoids
what 2 conditions make up COPD
chronic bronchitis
emphysema
what is chronic bronchitis
inflammation of bronchi/bronchioles
what does emphysema result in
distension + damage to alveoli
what receptor causes contraction of the airways in COPD
muscarinic acetylchloline (M3) receptor
how does muscarinic acetylchloline (M3) receptor causes contraction of airway smooth muscle
stimulation of M3 leads to release of Ca2+ from Sarcoplasmic reticulum which causes contraction
what does stimulation of muscarinic acetylchloline (M1) receptor result in
fast neurotransmission
what is stimulation of muscarinic acetylchloline (M1) receptor mediated by
ACh acting on nicotinic receptors
what does stimulation of muscarinic acetylchloline (M2) receptor result in
inhibition of ACh release
what does stimulation of muscarinic acetylchloline (M3) receptor result in
airway smooth muscle contraction
treatment of COPD
SAMA LAMA SABA LABA ICS
can you mix SAMA and LAMA
No
give an example of a SAMA
ipratropium
give an example of LAMA
tiotropium
what is the mechanism of action for ipratropium
it is an non-selective, anti-cholinergic bronchodilator
why is it not useful to block M2 receptors in COPD
active M2 receptors will inhibit further ACh release
what are LABA/SABA used for
bronchodilation
what drugs are used in the treatment of allergic and non-allergic rhinitis (4)
- steroids = anti-inflammatory
- antihistiamines
- cysLT’s
- sodium cromoglicate
what is the mechanism of action of antihistiamines
competitive antagonists of H1 receptors = reduces effects of mast cells
what muscarinic acetylchloline receptors does ipratropium block
M1, M2, M3
what muscarinic acetylchloline receptors does tiotropium block
M3
describe the selectivity of tiotropium
M3 selective
describe the selectivity of ipratropium
NON-selective
give an example of PDE4 inhibitor
Romfumilast
what does the drug “Romfumilast” do?
suppresses inflmaation and emphysema in COPD
what is Phosphodiesterase-4 (PDE4)
the main PDE expressed in neutrophils, T cells and macrophages
what cells express PDE
neutrophils
T cells
macrophages
how are cromones administered
inhaled
when would “Romfumilast” be used
as an add on to ICS + LABA+ LAMA
fairly last line
what do mucolytics do
reduce sputum viscosity and aid sputum expectoration
rarely used
where are M1 receptors located
ganglia
where are M2 receptors located
postganglionic neurone terminals
where are M3 receptors located
ASM
how are SAMAs administered
via inhalation
how are LAMAs administered
via inhalation
how do LAMA and SAMA drug names end
“-ium”
what type pf ammonium group is found on SAMAs and LAMAs, what charge does it have
quaternary
postive charge
LAMA/SAMA blocks which reflex
cough reflex
how do SABA drug names end
“-mol”
how do LABA drug names end
“-rol”
explain the logic behind combining SABA/SAMA or LABA/LAMA
SABA = causes relaxation
SAMA = prevents contraction
SYNERGISTIC ACTIONS