Pharmacology asthma COPD Flashcards
Asthma
Inflammatory condition with recurrent reversible airway obstruction due to stimuli too weak to affect non asthmatic people
Symptoms of asthma
Wheezing
Shortness of breath especially breathing out
Cough sometimes
Difference between asthma and COPD
In asthma , airway obstruction is reversible
COPD , obstruction not reversible or partially reversible
Status asthmaticus
Acute severe asthma which is not easily reversible and can cause hypoxemia which requires hospitalization because fatal
Asthma 3 characteristics
Bronchial hyperactivity
Reversible broncho constriction
Airways inflammation
Immediate phase of asthma
Stimulus binds and activate mast cell
Mast cells release spasm ovens (cysLTs, histamine and PGD2) —> bronchospasm
Mast cells release chemotaxins and chemokines which lead to late phase
Drugs classes that can revert bronchospams effet in immediate phase
B2 adrenoreceptors agonists
CystLT receptor antagonists
Theophylline
Late phase of asthma
Infiltration of cytokines
Release of Th2 cells , monocytes
Activation of inflammatory cells specially eosinophils
Release of mediatiors (cysLTs, neuropeptides, NO, adenosine) and EMBO, ECP ( cause epithelial damage) —> airway inflammation and hyper reactivity —-> bronchospam, wheezing, coughing
Drugs that can act in late phase of asthma
Glucocorticoids
Drug therapy for asthma
Bronchidilators ( reverse brinchospam)
Anti inflammatory agent (prevent or inhibit inflammation)
Types of bronchodilators
B2 adreno receptors agonists
Xanthines
Cysteinyl Leukotriene receptor antagonists
Muscarinic receptor antagonists
Effect of B adrenoreceptor agonist
Dilate bronchi by direct action On smooth muscle no matter stimulus
Inhibit mediator release from mast cells
Inhibit TNF à release from monocytes
Increase mucus clearance by cilia action
Mode of administration of b adrenoreceptor agonists
Inhalation (metered dose inhaler ) oral Powder Nébulisation Orally Injection
B adrenoreceptor agonists short acting
Inhalation :
Salbutamol Terbutaline Metaproterenol Levalbuterol Pirbuterol
Short acting b adrenorefeotor agonist duration of action
3-5h so used on “as needed” basis
Long acting b adrenoreceptor agonist
Inhalation:
Salmeterol
Formoterol
Vilanterol
Long acting b adrenorefeotor agonist duration of action
8-12h
Given regularly twice daily when asthma of patient inadequately controlled by glucocorticoids
B adrenoreceptor agonist combination
Albuterol + ipratropium
Salmeterol+ fluticasone
Formoterol+ moments some
Formoterol + budesonide
Vilanterol + fluticasone
B adrenoreceptor agonist unwanted effects
Tremor
Tachycardia
Cardiac dysrhythmia
Xanthines agents
Theophylline
Aminophylline
Xanthine action
Relaxant effect on smooth muscle by inhibit phosphodiestarase isoenzymes -> Increase in cAMP
Antiinflammatory action by inhibit type IV phosphodiesterase which is involved in inflammation
Theophylline interaction with glucocorticoid
Activates histone deacetylase so can reverse resistance to anti inflammatory effect of corticosteroids
Methylxanthine impact on CNS and respiratory system
Stimulate it so can be beneficial in COPD patients with reduced respiration with CO2 retention
Therapeutic index of theophylline
Narrow 30-100 micromol
Adverse effect at 110
Side effects of theophylline
Act on CNS CVS GI diuresis
Cause insomnia , nervousness etc
What happens when xanthines concentration goes above 200
Serious CVS and CNS effects
Dysrhythmias which can be fatal
Seizures (fatal if respiration impaired )