| Question | Answer |
| 1. In which cells is histamine stored?
2. Where are these cells found? | 1. within vesicles or basophils and mast cells
2. basophils are in blood; mast cells are in tissue |
| What GPCR do the following act through? Which tissues are they found in?
1. H1 histamine receptor
2. H2 histamine receptor | 1. Gq; airway smooth muscle, endothelium
2. Gs; gastric parietal cells, cardiac muscle, mast cells |
| What effect does histamine have on:
1. Vasculature
2. Respiratory tract | 1. vasodilation (vessel permeability)
2. bronchoconstriction, mucus & sputum production |
| Mechanism of action of:
1. antihistamines
2. Nasal decongestants
3. expectorants | 1. competitively inhibit H1 receptors
2. alpha-adrenergic agonists
3. ↑ sputum production |
| 1. mechanism of action of Dornase alfa.
2. What is its clinical use? | 1. mucolytic; hydrolyzes extracellular DNA in mucus
2. cystic fibrosis |
| What are the 2 classes of H1 antihistamines? | 1. 1st Gen: "sedating"
2. 2nd Gen: "non-sedating" |
| 1. Why do 1st generation H1 antihistamines cause sedation?
2. How does affinity to H1 receptor change over the generations of antihistamines? | 1. cross the blood-brain barrier and block muscarinic receptors in the CNS
2. 1st gen. have the lower affinity while 2nd gen. have higher affinity |
| Why are some antihistamines effective against motion sickness and not others? | the first generation antihistamines have antimuscarinic action and are effective against motion sickness |
| 1. Dephenhydramine mechanism of action
2. Uses | 1. (trade name Benadryl - 1st gen antihistamine)
2. symptomatic relief of allergic symptoms, sleep aid, treatment of motion sickness |
| Which CNS conditions are H1 antihistamines effective against? | 1. motion sickness
2. vertigo
3. sedation
4. emesis |
| What are the side effects of first generation H1 antihistamines? | 1. sedation
2. anticholinergic effects (blurry vision, dry mouth)
3. long QT/arrhythmias (K+ channel block) |
| 1. What is a decongestant?
2. What is an example? | 1. a drug that reduces nasal or oropharyngeal mucosal swelling by constricting blood vessels in the submucosal tissue
2. phenylephrine |
| 1. Drug of choice for immediate anaphylactic shock.
2. What is the mechanism of action of nasal decongestants? | 1. epinephrine
2. alpha-adrenergic agonists |
| 1. Treatment of allergic conjunctivitis
2. What is the mechanism of action?
3. adverse effect | 1. Naphcon and visine eyedrops
2. H1 antihistamine
3. ↑ intraocular pressure → ↑risk for glaucoma |
| 1. Mechanism of action of central antitussives?
2. Which drugs are in this class? | 1. agonist of opiate receptor in medulla
2. codeine, hydrocodone |
| Mechanism of action
1. Albuterol
2. Salmeterol
3. Theophylline | 1. β2 agonist → bronchodilation
2. β2 agonist → bronchodilation
3. inhibits phosphodiesterae → ↑ cAMP and bronchodilation; also blocks adenosine's bronchoconstrictive action |
| Adverse effects of:
1. salmeterol
2. theophylline | 1. tremor, arrhythmia
2. cardiotoxicity, neurotoxicity |
| Mechanism of action:
1. Ipratropium
2. Cromolyn | 1. muscarinic antagonist, prevents bronchoconstriction
2. prevents release of mediators from mast cells |
| Corticosteroids
1. Mechanism of action
2. examples | 1. inhibit synthesis of cytokines; inactivate NF-kB →↓inflammatory agents
2. Beclomethasone, prednisone |
| Mechanism of action:
1. Zileuton
2. Zafirlukast, montelukast | 1. 5-lipoxygenase pathway inhibitor
2. block leukotriene receptors |
| 1. Expectorant that removes mucus but does not relieve cough
2. Expectorant loosens mucus plugs in CF patients. | 1. Guaifenesin (Robitussin)
2. N-acetylcysteine |
| 1. Treatment for pulmonary hypertension
2. mechanism of action | 1. Bosentan
2. competitively antagonizes endothelin-1 receptors → ↓pulmonary vascular resistance |
| Used for aspirin induced asthma. | Zafirlukast, montelukast |
| 1. β2 agonist used for acute exacerbation of asthma
2. β2 agonist used for long action prophylaxis. | 1. Albuterol
2. Salmeterol |
| 1. Mechanism of action of N-acetylcystein as a decongestant?
2. Mechanism by which N-acetylcystein can decrease cough? | 1. breaks disulfide bond links in mucin oligomers
2. decreases free radical injury and inflammation |
| 1. What are the three major antihistamines that have no CNS entry?
2. What is the only pharmacologic use?
3. Antitussive that blocks stretch receptors in throat. | 1. Cetirizine, Loratadine, Fexofenadine
2. allergic reactions (seasonal rhinitis)
3. Benzonatate |
| 1. How are all antihistamines metabolized?
2. Antihistamine that is highly effective in motion sickness.
3. Mechanism of action of Dextromethorphan | 1. hepatic cytochrome P450
2. meclizine
3. centrally acting antitussive that binds NMDA receptors |
| 1. Treatment for aspirin induced asthma
2. Cetirizine
3. Used to treat bronchospasm caused by β blockers | 1. Zafirlukast, montelukast
2. 2nd generation antihistamine; trade name Zyrtec
3. muscarinic receptor blockers (Ipratropium) |
| Histamine effect on the heart
1. H1 receptors
2. H2 receptors | 1. ↓ AV nodal conduction
2. ↑ SA nodal rate, positive inotropism |
