Respiratory Flashcards
What is the mechanism of H1 blockers?
Reversible inhibitors of H1 histamine receptors
What are the 1st generation H1 blockers?
Diphenhydramine, dimenhydrinate, chlorpheniramine.
Names contain “-en/-ine” or “-en/-ate.”
What are the clinical uses of the 1st generation H1 blockers?
Allergy, motion sickness, sleep aid.
What are the toxicities of the 1st generation H1 blockers?
Sedation, antimuscarinic, anti-α-adrenergic.
What are the 2nd generation H1 blockers?
Loratadine, fexofenadine, desloratadine, cetirizine.
Names usually end in “-adine.”
What is the clinical use of the 2nd generation H1 blockers?
Allergy
What are the toxicities of the 2nd generation H1 blockers?
Far less sedating than 1st generation because of ↓ entry into CNS.
Expectorants - What are the features of Guaifenesin?
Expectorant—thins respiratory secretions; does not suppress cough reflex.
Expectorants - What are the features of N-acetylcysteine?
Mucolytic—can loosen mucous plugs in CF patients. Also used as an antidote for acetaminophen overdose.
What are the features of Dextromethorphan?
Antitussive (antagonizes NMDA glutamate receptors). Synthetic codeine analog. Has mild opioid effect when used in excess. Naloxone can be given for overdose. Mild abuse potential.
What is the mechanism of Pseudoephedrine and phenylephrine?
Sympathomimetic α-agonistic nonprescription nasal decongestants.
What is the clinical use of Pseudoephedrine and phenylephrine?
Reduce hyperemia, edema, and nasal congestion; open obstructed eustachian tubes. Pseudoephedrine also illicitly used to make methamphetamine.
What are the toxicity of Pseudoephedrine and phenylephrine?
Hypertension. Can also cause CNS stimulation/anxiety (pseudoephedrine).
How is Asthma therapy directed?
Bronchoconstriction is mediated by (1) inflammatory processes and (2) parasympathetic tone; therapy is directed at these 2 pathways.
Asthma (β2-agonists) - What are the features of Albuterol?
Relaxes bronchial smooth muscle (β2). Use during acute exacerbation.
Asthma (β2-agonists) - What are the features of Salmeterol and formoterol?
Long-acting agents for prophylaxis. Adverse effects are tremor and arrhythmia.
Asthma - What are the features of Methylxanthines?
Theophylline—likely causes bronchodilation by inhibiting phosphodiesterase → ↑ cAMP levels due to ↓ cAMP hydrolysis. Usage is limited because of narrow therapeutic index (cardiotoxicity, neurotoxicity); metabolized by cytochrome P-450. Blocks actions of adenosine.
Asthma - What are the features of Muscarinic antagonists?
Ipratropium—competitive block of muscarinic receptors, preventing bronchoconstriction. Also used for COPD, as is tiotropium, a long-acting muscarinic antagonist.
Asthma - What are the features of corticosteroids?
Beclomethasone, fluticasone—inhibit the synthesis of virtually all cytokines. Inactivate NF-κB, the transcription factor that induces the production of TNF-α and other inflammatory agents. 1st-line therapy for chronic asthma.
Asthma - What are the features of Antileukotrienes?
Montelukast, zafirlukast—block leukotriene receptors. Especially good for aspirin-induced asthma.
Zileuton—a 5-lipoxygenase pathway inhibitor. Blocks conversion of arachidonic acid to leukotrienes.
Asthma - What are the features of Omalizumab?
Monoclonal anti-IgE antibody. Binds mostly unbound serum IgE and blocks binding to FcεRI. Used in allergic asthma resistant to inhaled steroids and long-acting β2-agonists.
What are the features of Methacholine?
Muscarinic receptor agonist. Used in bronchial provocation challenge to help diagnose asthma.
What are the features of Bosentan?
Used to treat pulmonary arterial hypertension. Competitively antagonizes endothelin-1 receptors, ↓ pulmonary vascular resistance.
Describe the pathway towards asthma.
Therapy is in [ ]
Exposure to antigen (dust, pollen, etc.) [Avoidance] → Antigen and IgE on mast cells [Omalizumab] → [Steroids] Mediators (leukotrienes, histamine, etc.) →
a) [Steroids, Antileukotrienes] → Late response: inflammation → Bronchial hyperreactivity
b) [β-agonists, Theophylline, Muscarinic antagonists] → Early response: bronchoconstriction → Symptoms
Asthma - What are the features of corticosteroids?
Beclomethasone, fluticasone—inhibit the synthesis of virtually all cytokines. Inactivate NF-κB, the transcription factor that induces the production of TNF-α and other inflammatory agents. 1st-line therapy for chronic asthma.
Asthma - What are the features of Antileukotrienes?
Montelukast, zafirlukast—block leukotriene receptors. Especially good for aspirin-induced asthma.
Zileuton—a 5-lipoxygenase pathway inhibitor. Blocks conversion of arachidonic acid to leukotrienes.
Asthma - What are the features of Omalizumab?
Monoclonal anti-IgE antibody. Binds mostly unbound serum IgE and blocks binding to FcεRI. Used in allergic asthma resistant to inhaled steroids and long-acting β2-agonists.
What are the features of Methacholine?
Muscarinic receptor agonist. Used in bronchial provocation challenge to help diagnose asthma.
What are the features of Bosentan?
Used to treat pulmonary arterial hypertension. Competitively antagonizes endothelin-1 receptors, ↓ pulmonary vascular resistance.
Describe the pathway towards asthma.
Therapy is in []
Exposure to antigen (dust, pollen, etc.) [Avoidance] → Antigen and IgE on mast cells [Omalizumab] → [Steroids] Mediators (leukotrienes, histamine, etc.) →
a) [Steroids, Antileukotrienes] → Late response: inflammation → Bronchial hyperreactivity
b) [β-agonists, Theophylline, Muscarinic antagonists] → Early response: bronchoconstriction → Symptoms
What can Methemoglobinemia be treated with?
Methylene blue
How do you treat cyanide poisoning?
Use nitrites to oxidize Hb to methemoglobin, which binds cyanide. Use thiosulfate to bind this cyanide, forming thiocyanate, which is renally excreted.
A response to high altitude is ↑ renal excretion of HCO3- to compensate for respiratory alkalosis. What drug can augment this?
Acetazolamide
How do you treat Deep venous thrombosis?
Use heparin for prevention and acute management; use warfarin for long-term prevention of DVT recurrence.
What drugs cause interstitial lung diseases (pulmonary ↓ diffusing capacity, ↑ A-a gradient)?
Bleomycin, busulfan, amiodarone, methotrexate
