Smooth Muscle Part 1 Flashcards
what are the 3 big things that happen with asthma?
- narrowing of airways
- increased mucus production
- inflammation
what are the clinical characteristics of asthma?
- recurrent bouts of SOB
- chest tightness
- coughing
- wheezing
pathophysiology of asthma
- widespread, reversible narrowing of bronchial airways
- significant bronchial responsiveness to inhaled stimuli
pathology of asthma
- lymphocytic and eosinophilic inflammation of the bronchial mucosa 2. “remodelling” of the bronchial mucosa –> hyperplasia of the cells of the airway walls
what are the pharmacologic goals in the management of asthma
- treatment (w/ short-term relievers and long-term controllers) 2. prevention of inflammation, bronchoconstriction, and mucus
T/F: the more uncontrolled asthma is the more mucus production there is
TRUE
mild asthma
- occasional
- triggered via: exposure to allergens, pollutants, viral URI, and/or during exercise
severe asthma
- frequent
- associated with wheezing and dyspnea
- exacerbations occur often at night 4. chronic airway narrowing with chronic respiratory impairment
detail the pathogenesis (conceptual theory model) of asthma
- exposure to allergen –> synthesis of IgE –> binds to mast cells in airway mucosa
- on re-exposure to allergen –> Ag/Ab complex on mast cell surgace triggers release of mediators and anaphylaxis (histamine, tryptase, prostaglandin D2, leukotriene C4, and plt activating factor)
- these agents provoke contraction of airway smooth muscle –> immediate fall in FEV1
- re-exposure to allergen also causes the synthesis and release of a variety of cytokines
- these cytokins attract and activate eosinophils and neutrophils (which release mediators)
- mediator release –> edema, mucus hypersecretion, smM contraction, and increased bronchial reactivity associated with late asthmatic response indicated by second fall in FEV1 3-6 hours after exposure
bronchodilation is promoted by what secondary messenger?
cAMP
how do beta agonists promote bronchodilation with asthma?
increases cAMP by increasing the rate of cAMP synthesis via adenylyl cyclase
how do phosphodiesterase inhibitors, like theophylline promote bronchodilation in asthmatics
increases cAMP, by slowing the degradation of cAMP
what two med categories cause bronchodilation with asthma therapy by increasing cAMP?
- beta agonists
- PDE inhibitors (theophylline)
what class of medications tend to promote bronchodilation by inhibiting bronchoconstriction in asthma therapy
- muscarinic antagonists (M3)
- adenosine antagonists (theophylline)
which drug works in asthma therapy by both promoting bronchodilation through increasing intracellular cAMP and by inhibiting bronchoconstriction through adenosine antagonism?
theophylline
T/F: no med guarantees the break of a bronchospasm
TRUE
if a patient has a bronchospasm what should you do?
- take them off the vent and bag - seeing if you can move air 2. if you cannot move air –> no INH med, give double diluted epi IV 3. if can move air –> albuterol
what are the different symapthomimetics given for asthma ?
- epi (IV, INH, SQ)
- ephedrine
- isoproteronol
- albuterol (po, INH)
- terbutaline (PO, SQ, INH)
- metaproterenol (INH)
- Pirbuterol (INH)
epinephrine is a very effective bronchodilator that stimulates the ________& __________ receptor
alpha; B1
what meds were displaced (replaced) by beta 2 selective agents in asthma therapy
- epi 2. ephedrine
problematic s/e with using epinephrine with asthma?
tachycardia, arrhythmias, angina
compared to epi, what is different about ephedrine for use in asthma tx
- longer DOA
- oral availablity
- increased CNS effects
- decreased potency
why is isoproternol not used in asthma tx that often anymore
increased mortality 2/2 cardiac arrhythmias from high dose inhaled isopro
what are your long acting B2 agonists used in the tx of asthma?
- salmeterol
- formeterol
- indacaterol (COPD only!)
characteristics of long acting beta 2 agonist
- highly lipid soluble 2. have to be combined with steroids
why do long acting beta 2 agonists like salmeterol and formeterol have to be combined with corticosteroids in the tx of asthma?
they have no anti-inflammatory effects; thus cannot be used as monotherapy
black box warning for long acting beta 2 agonists (salmeterol, formeterol, and indacaterol)
small but significant increase in the risk of death/near death from asthma attack, esp in african americans
T/F: you can use a NMB to break a bronchospasm
false; bronchospasm is smM, NMBA only work on skM (thus can use to break laryngospasm)
MOA of albuterol
- Beta-2 selective agonist
- relaxes airway smooth muscle by inhibiting bronchoconstricting mediators from mast cells
- inihbits microvascular leakage
- increases mucociliary transport via increased ciliary activity
- stimulates adenylyl cyclase to increase cAMP –> bronchodilation
albuterol systemic effects
- bronchodilation
- increase shunt (great perfusion, no oxygenation)
- tachycardia (B1)
- vasodilation (B2)
- potential for arrhythmias
- tremors
- increases activity of Na/K pump –> decrease potassium levels
how do you prevent the increasing of a pulmonary shunt with albuterol?
administer with O2
which can administer higher dose of medication? MDI or Neb?
nebulizer