Respiratory Pharm Flashcards
H1 blockers
Reversible inhibitors of H1 histamine receptors
1st generation H1 blockers:
Diphenhydramine, dimenhydrinate, chlorpheniramine
Names contain “-en/-ine” or “-en/-ate”
Clinical uses of 1st gen H1 blockers:
Allergy, motion sickness, sleep aid
Toxicity of 1st gen H1 blockers:
Sedation, antimuscarinic, anti-alpha-adrenergic
2nd generation H1 blockers:
Loratadine, fexofenadine, desloratadine, cetirizine.
Names usually end in “-adine”
Clinical uses of 2nd generation H1 blockers:
Allergy
Toxicity of 2nd generation H1 blockers
Far less sedating than 1st generation because of decreased entry into CNS
Guaifenesin
Expectorant - thins respiratory secretions; does not suppress cough
N-acetylcysteine
Mucolytic - can loosen mucus plugs in CF patients. Also used as an antidote for acetaminophen overdose.
Cleaves disulfide bonds within mucus glycoproteins.
Dextromethorphan
Antitussive (antagonizes NMDA glutamate receptors).
Synthetic codeine analog.
Mild opioid effect when used in excess.
Mild abuse potential
May cause serotonin syndrome if combined with other serotonergic agents.
Drug given for overdose of Dextromethorphan
Naloxone
Pseudoephedrine, phenylephrine mechanism:
sympathomimetic alpha-agonistic nonprescription nasal decongestants
Pseudoephedrine, phenylephrine clinical use:
Reduce hyperemia, edema and nasal congestion; open obstructed eustachian tubes.
Pseudoephedrine used illicitly to make methamphetamine
Pseudoephedrine, phenylephrine toxicity:
Hypertension. Can also cause CNS stimulation/anxiety (pseudoephedrine)
Endothelin R Antagonists:
Include Bosentan. Competetively antagonize endothelin-1 R’s. Leads to decreased pulmonary vascular resistance.
Hepatotoxic (monitor LFT’s)
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) w/vasodilatory effects on pulmonary and systemic arterial vascular beds. Inhibits platelet aggregation.
Side effects: flushing, Jaw pain
Asthma drugs:
Bronchoconstriction is mediated by 1. inflammatory processes, and 2. parasympathetic tone; therapy is directed at these 2 pathways
B2-agonist:
Albuterol, Salmeterol, formoterol
Used in asthmatics
Albuterol:
B2-agonist. Relaxes bronchial smooth muscle. Use during acute exacerbation of asthma.
Salmeterol, formoterol
Long acting B2 agonists for asthma prophylaxis. Adverse effects are tremor and arrhythmia.
Methylxanthines
Theophylline
Theophylline
Methylxanthine that likely causes bronchodilation by inhibiting phosphodiesterase (use in asthmatics). Increases cAMP levels, due to decreased cAMP hydrolysis.
Usage is limited by narrow therapeutic index (cardiotoxicity, neurotoxicity, ex. arrhythmias and seizures)
Metabolized by P-450.
Blocks actions of adenosine (a bronchoconstrictor)
Muscarinic antagonists:
Ipratropium (Atrovent)
Ipratropium
Competitive block of muscarinic receptors, preventing bronchoconstriction (use in asthmatics). Also used for COPD, as is tiotropium, a long acting muscarinic antagonist.
Often used with albuterol.
Corticosteroids:
Beclomethasone, fluticasone, Budesonide
Beclomethasone, fluticasone, Budesonide:
Inhibit the synthesis of virtually all cytokines. Inactivate NF-KB, transcription factor that induces production of TNF-a and other inflammatory agents. 1st line therapy for chronic asthma (everyday inhaled)
Antileukotrienes:
Montelukast, Zafirlukast, Zileuton
Montelukast, Zafirlukast
block leukotriene receptors (CysLT1). Especially good for aspirin induced asthma. $$$
Zileuton
5-lipoxygenase pathway inhibitor. Blocks conversion of arachidonic acid to leukotrienes. $$
SE: hepatotoxicity
Omalizumab
Monoclonal anti-IgE antibody.
Binds mostly unbound serum IgE and blocks binding to FcERI.
Used in allergic asthma resistant to inhaled steroids and long acting B2 agonists.
Methacholine
Muscarinic receptor agonist. Used in bronchial provocation challenge to help diagnose asthma
Asthmatics have exaggerated response to low doses
Bosentan
Used to treat pulmonary arterial hypertension. Competitively antagonizes endothelin-1 receptors, decreasing pulmonary vascular resistance.
Cromolyn Sodium:
Mast cell stabilizer - prevents histamine release from mast cells. Only prophylactic use. Largely replaced by leukotriene antagonists (zileuton). $$$
Terbutaline
B2 agonist. Bronchodilator (reliever inhaler)
Off label use: oral, stop premature contractions (delay labor 48 hours)
Tiotropium:
long acting muscarinic antagonist - often used with albuterol
