pharmacology of the airways Flashcards
what are the 3 main ways in which drugs affect cells + examples
- direct effect on membrane permeability e.g. Ach binding to nicotinic receptors;
- effect via intracellular messenger e.g. B-adrenergenic receptor binding;
- effect on DNA transcription e.g. oestrogen receptor
what are the main receptors involved in bronchodilation
B2 adrenergic
why is salbutomol generally the SABA of choice in asthma (receptors)
has high specificity for being a B2 receptor agonist without activating (or lesser activation of) other adrenergic receptors (e.g. B1 which would result in tachycardia, a1/2)
why must you be careful when prescribing BB for a cardiac condition in someone with asthma
many BBs are both B1 and B2 antagonists and so may cause bronchoconstriction and thus make the asthma worse e.g. atenolol
SABA/LABA, LAMA, ICS endings
SABA/LABA - ol
LAMA -ium
ICS - one
examples of SABA
salbutamol, terbutaline
examples of LABA
formoterol, serevent
examples of ultra LABA
indacaterol, vilanterol, olodaterol
examples of SAMA
ipratropium
examples of LAMA
tiotropium; glycopyrronium; aclidinium
what do corticosteroids down regulate (8)
inflammatory cells: eosinophils, t-lymphocyte, mast cell, macrophages, dentritic cells;
structural cells: epithelial cytokine mediators, endothelial cell leakage, mucous secretion
(and upregs B2 receptors -> bronchodilation)
what condition can occur with steroid overuse
cushing’s syndrome
symptoms of cushing’s syndrome (7)
moon face; purple striae; bruises and petechiae; trunkal obesity (and thin extremities); personality change; hyperglycaemia; Na+ and fluid retention (oedema)
what can occur if steroids are too quickly withdrawn and why
addisonian crisis - body has downregulated its own production of steroids and so sudden withdrawal will cause crisis
Addisonian (adrenal) crisis presentation
hypotension; malaise; fatigue; muscle pain; abdominal pain; electrolyte imbalance; hypovolaemic shock may occur
examples of leukotriene receptor antagonist
monteleukast, zafirlukast, pranlukast
LTRA MOA
Leukotrienes are synthesized from arachidonic acid by the action of 5-lipoxygenase in many inflammatory cells in the airways - act as antagonists to this pathway (cysLTI)
what are the inflammatory effects of leukotrienes
increased mucous secretion; decreased mucous transport; eosinophil recruitment; tachykinin release; smooth muscle contraction and proliferation; increased blood vessel leakage
when are cromones indicated and what is their MOA
as an add on treatment for asthma, often in children;
MOA - mast cell stabilisation (affect histamine and bradykinin release)
what is the aim of using monoclonal antibodies in asthma treatment
downregulate IgE and eoisinophils
what are xanthine derivatives used for and what to they act on
inhibite phophodiesterase; act to relieve bronchospasm caused by asthma or chronic obstructive lung disease
why are xanthines uncommonly used
low therapeutic range - may be toxic at therapeutic levels
examples of mucolytics
carbocisteine; erdosteine; mecysteine
when are mucolytics indicated
used to manage mucus hypersecretion and its sequelae like recurrent infections in patients of COPD, cystic fibrosis, and bronchiectasis
