Question | Answer |
early phase of asthma | bronchospasm |
late phase of asthma | inflammation |
B2 agonists (albuterol, salmeterol) MOA | relaxation of bronchiole smooth muscle |
mast calls & T-lymphocytes release which mediators | histamine, tryptase, PGD2, LTC4, PAF, IL-4, IL-5, GM-CSF, TNF, TGF |
eosinophils and neutrophils release which mediators | ECP, MBP, Protease, PAF |
corticosteriods (beclomethasone, budesonide) MOA | broad anti-inflammatory actions |
methylxanthines (theophylline) MOA | relaxation of bronchiole smooth muscle, effects on T-cells & eosinophils, increased mucociliary clearance (all via increase in cAMP) |
cromolyn, nedocromil MOA | inhibit release of inflammatory mediators |
leukotriene modifiers (zafirlukast, montelukast) MOA | antagonize the actions of LTs in the airways |
muscarinic antagonists (ipratropium) MOA | muscarinic blockade in airways (blocks parasympathetic bronchoconstriction) |
monoclonal antibodies (omalizumab) MOA | block IgE binding to mast cells |
non-selective beta-agonists (3) used for asthma | epinephrine, ephedrine, isoproterenol |
epinephrine - forms, onset & DA, adv rxns | injectable, aerosolinhalation: onset in 15 minduration: 60-90 minadv rxn: tachycardia, arrythmias, MI, skeletal muscle tremor |
ephedrine for asthma (compared to epi) | oral adm; longer acting; more CNS effects; less potent |
isoproterenol for asthma (compared to epi) | more potent; short onset of 5 min; 60-90 min duration |
B2-selectives - onset, peak and DA if inhaled | onset at 1-5 min; peak at 30 min; lasts for 2-6 hrs |
B2-selectives - oral DA | ~ 4-8 hrs |
B2-selective drugs | albuterol (O/I), terbutaline (O/I), metaproterenol (O/I), bitolterol, pirbuterol, levalbuterol, salmeterol, formoterol |
long-acting B2-selective drugs (12 hours or longer - useful for nocturnal symptoms) | salmeterol, formoterol --> both are dry powder inhalers |
% of dose from MDI that actually makes it into the lung | 2 - 10% (90% deposited in the mouth) |
tolerance to B2-selective agents tends to develop in response to which effect | tolerance to anti-inflammatory effects (mast cells and lymphocyets) more than tolerance to brochodilation |
drug interaction with selective B2 agonists | interaction b/w non-selective beta-blockers and selective B2 agonist (counteract one aother) |
Methylxanthine drugs (4) | theophylline, aminophylline, enprofylline (3-propylxanthine), and Roflumilast (newest agent in clinical trials) |
two proposed methylxanthine MOA's (theophylline, aminophylline) | Increased cAMP results in:1) inhibtion of PDE4 (requires high conc.), 2) blockade of adenosine receptors, A1 in bronchiole sm (seen at therapeutic concentrations) |
therapeutic index/range for methylxanthine drugs (theophylline, aminophylline) | 10-20 micrograms/ml (SEs appear around 20-25 micrograms/ml; higher than 40 can lead to seizures or arrhythmias) |
metabolism of methylxanthines (theophylline, aminophylline) | CYP 450: 1A2 --> drug interactions |
what's special about roflumilast | newest methylxanthine in clinical trials - high specificity for PDE4 in the lungs, less AE |
what's special about enprofylline | potent bronchodilator that shows PDE4 inhibition, but no adenosine receptor antagonism |
muscarinic antagonists for asthma (2) | Ipratropium & Tiotropium: Ipratropium bromide (quaternary ammonium compound)Tiotropium (Spiriva) – new agent with 24-hr duration of action |
muscarinic antagonists (Ipratropium & Tiotropium) - MOA | blocking muscarinic receptors prevents parasympathetic bronchoconstriction - M3 receptor |
which disease state should muscarinic antagonists be used carefully in | glaucoma |
muscarinic antagonists (Ipratropium & Tiotropium) - time to peak, DA | Max effect in 30 min; duration of 3-5 hrs |
Combivent (MDI) - 2 products | albuterol (b2 selective agonist) + ipratropium (muscarinic antagonist) |
MOA for Cromolyn (Intal) & Nedocromil (Tilade) | inhibition of mast cell degranulation; inhibit mediator release from bronchial mast cells inhibition of parasympathetic & cough reflexes; not bronchodilators; no direct effects on smooth muscle |
uses for for Cromolyn (Intal) & Nedocromil (Tilade) (mast cell degranulation inhibitors) | only prophylactic use – decrease immediate & late-phase asthmatic response to antigen-, exercise-, and irritant-induced asthma; effective when given before exercise or exposure to irritants |