deck_3452463 Flashcards
How do H1 blockers work?
Reversible inhibitors of H1 histamine receptors.
What are the 1st generation H1 blockers?
- Diphenhydramine2. Dimenhydrinate3. Chlorpheniramine
Diphenhydramine
first generation H1 blocker
Dimenhydrinate
first generation H1 blocker
Chlorpheniramine
first generation H1 blocker
What are the clinical uses of 1st generation H1 blockers?
- Allergy- Motion skickness- sleep aid
What are first generation H1 blocker toxicities?
- sedation- antimuscarinic- anti alpha adrenergic
What are the 2nd generation H1 blockers?
- Loratadine2. Fexofenadine3. Desloratadine4. Cetirizine
What are the clinical uses of 2nd generation H1 blockers?
Allergy
What are the second generation H1 blocker toxicities?
Far less sedating than 1st generation because of ↓ entry into CNS.
Loratadine
2nd generation H1 blocker
Fexofenadine
2nd generation H1 blocker
Desloratadine
2nd generation H1 blocker
Cetirizine
2nd generation H1 blocker
Expectorant
- thins respiratory secretions - does not suppress cough reflex
Guaifenesin
Expectorant - thins respiratory secretions; does not suppress cough reflex.
N-acetylcystein
Mucolytic - can loosen mucous plugs in CF patients by disrupting disulfide bonds. Also used as an antidote for acetaminophen overdose.
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. May cause serotonin syndrome if combined with other serotonergic agents.
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. May cause serotonin syndrome if combined with other serotonergic agents.
Dextromethorphan
Mucolytic - can loosen mucous plugs in CF patients by disrupting disulfide bonds. Also used as an antidote for acetaminophen overdose.
N-acetylcystein
Expectorant - thins respiratory secretions; does not suppress cough reflex.
Guaifenesin
Pseudoephedrine, phenylephrine mechanism
α-adrenergic agonists, used as nasal decongestants
α-adrenergic agonists, used as nasal decongestants
pseudoephedrine, phenylephrine
Pseudoephedrine, phenylephrine clinical use
- reduce hyperemia, edema, nasal congestion2. open obstructed eustachian tubesPseudoephedrine also illicitly used to make methamphetamine.
Pseudoephedrine, phenylephrine toxicity
Hypertension. Can also cause CNS stimulation/anxiety (pseudophedrine).
What are the pulmonary hypertension drugs?
- Endothelin receptor antagonist2. PDE-5 inhibitors3. Prostacyclin analogs
An example of Endothelin receptor antagonists
bosentan
An example of PDE-5 inhibitors
Sildenafil
An example of Prostacyclin analogs
Epoprostenoliloprost
Endothelin receptor antagonists
Include bosentan.Competitively antagonize endothelin-1 receptors → ↓ pulmonary vascular resistance.Hepatotoxic (monitor LFTs).
PDE-5 inhibitors
Include sildenafil. Inhibit cGMP PDE5 and prolong vasodilatory effect of nitric oxide. Also used to treat erectile dysfunction.
Prostacyclin analogs
Include epoprostenol, iloprost. Prostacyclins (PGI2) with direct vasodilatory effects on pulmonary and systemic arterial vascular beds. Inhibit platelet aggregation.Side effects: flushing, jaw pain.
How do asthma drugs work?
Bronchoconstriction is mediated by (1) inflammatory processes and (2) parasympathetic tone; therapy is directed at these 2 pathways.
Classes of asthma drugs
- β2-agonists2. Corticosteroids3. Muscarinic antagonists4. Antileukotrienes5. Omalizumab6. Methylxanthines
Methacholine
Muscarinic receptor (M3) agonist. Used in bronchial challenge test to help diagnose asthma.
Short term Beta-2 agonists
Albuterol.
Albuterol
Short term Beta-2 agonist. Relaxes bronchial smooth muscle (β2). Used during acute exacerbation.
Long term Beta-2 agonists
Salmeterol and formoterol.
Salmeterol
Long term beta 2 agonist. Long-acting agents for prophylaxis. Adverse effects are tremor and arrhythmia.
Formoterol
Long term beta 2 agonist. long-acting agents for prophylaxis. Adverse effects are tremor and arrhythmia.
What do beta 2 agonists do?
Relax bronchial smooth muscle (note that we’re talking about sympathetic stimulation relaxing bronchioles).Atp → [adenylyl cyclase] → cAMP → bronchodilation. Beta 2 agonists activate adenylyl cyclase to cause bronchodilation.
What do corticosteroids do?
Inhibit the synthesis of virtually all cytokines. Inactivate NF-κB, the transcription factor that induces production of TNF-α and other inflammatory agents. 1st-line therapy for chronic asthma.
Corticosteroids
Fluticasone and budesonide
fluticasone
Corticosteroid. Inhibits the synthesis of virtually all cytokines. Inactivate NF-κB, the transcription factor that induces production of TNF-α and other inflammatory agents. 1st-line therapy for chronic asthma.
budesonide
Corticosteroid. Inhibits the synthesis of virtually all cytokines. Inactivate NF-κB, the transcription factor that induces production of TNF-α and other inflammatory agents. 1st-line therapy for chronic asthma.
Muscarinic receptor (M3) agonist. Used in bronchial challenge test to help diagnose asthma.
Methacholine
Muscarinic antagonists
Ipatropium and tiotropium.
What do muscarinic antagonists do?
Competitively blocks muscarinic receptors, preventing bronchoconstriction. Also used for COPD. (Remember that parasympathetics are going to constrict the bronchioles).
Ipratropium
Muscarinic antagonist. Competitively blocks muscarinic receptors, preventing bronchoconstriction. Also used for COPD. (Remember that parasympathetics are going to constrict the bronchioles).
Tiotropium
Long acting muscarinic antagonist. competitively blocks muscarinic receptors, preventing bronchoconstriction. Also used for COPD. (Remember that parasympathetics are going to constrict the bronchioles).
Antileukotrienes
Montelukast, zafirlukast, and zileuton.
Montelukast
Antileukotriene. Block leukotriene receptors (CysLT1). Especially good for aspirin-induced asthma.
Zafirlukast
Antileukotriene. Block leukotriene receptors (CysLT1). Especially good for aspirin-induced asthma.
Zileuton
5-lipoxygenase pathway inhibitor. Blocks conversion of arachidonic acid to leukotrienes. Hepatotoxic.
Draw a diagram and show where antileukotrienes work
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.
Mexylthanthines
Theophylline
Theophylline
Mexylthanthine. Inhibits phosphodiesterase → ↑ cAMP levels due to ↓ cAMP hydrolysis.Atp → [adenylyl cyclase] → cAMP → bronchodilation.Usually PDE breaks down cAMP to AMP, theophylline prevents this from happening to increase cAMP.Usage is limited because of narrow therapeutic index (cardiotoxicity, neurotoxicity); metabolized by cytochrome P-450.Blocks actions of adenosine (causes bronchoconstriction).
What do mexylthanthines do?
Likely cause bronchodilation by inhibiting phosphodiesterase → ↑ cAMP levels due to ↓ cAMP hydrolysis.Narrow therapeutic index. Metabolized by P-450. Blocks the actions of adenosine.
Draw a diagram and show where beta agonists, mexylthanthines, and muscarinic antagonists work