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32 Cards in this Set
- Front
- Back
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Where is histamine stored?
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in mast cells, basophils, and neurons
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What is histamine synthesized from?
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histidine
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Histamine receptors are all part of the super family of...
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G-protein coupled receptors
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H1 is __ coupled and deals with...
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Gq coupled
allergy and motion sickness |
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H2 is __ coupled and deals with...
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Gs coupled
gastric acid release |
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H1 receptors are found in ...
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- bronchial smooth muscle
- intestinal smooth muscle - endothelium - CNS |
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H2 receptors are found in...
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- parietal cells
- vascular smooth muscle |
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What are the pathological effects of histamine?
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- uticaria (hives)
- anaphylactic shock - cardiac arrhythmia |
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What are the two types of histamine releasers?
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- immune
- non immune |
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What are the immune releasers of histamine?
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- food (grains, eggs, seafood)
- insect stings - venom - drugs (sulfonamide) - foreign substances (non-human insulin) |
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What is an example of a non immune histamine releaser?
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- drugs (such as vancomycin)
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Which drug causes "red man syndrome"?
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vancomycin
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When does the triple response of Lewis occur?
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It occurs in response to skin injury or histamine injection.
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What is the triple response of Lewis?
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1. small red spot forms (within seconds due to vasodilation)
2. spot grows (due to reflexive vasodilation) 3. wheal forms (due to endothelial permeability) |
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What are the classes of antihistamine drugs?
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- H1 receptor antagonists
- H2 receptor antagonists - Mast cell stabilizers |
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What are the uses for H1 receptor antagonists?
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- allergy treatment
- motion sickness and nausea (first generation only) - sedation (first generation only) - supplemental anaphylaxis treatment (with epi) |
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What are the first generation H1 receptor antagonists?
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- Chlorpheniramine
- Cyclizine* - Dimenhydrenate* - Diphenhydramine - Hydroxyzine - Meclizine* - Promethazine (used for nausea) * used primarily for motion sickness |
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What are the drug interactions for H1 receptor antagonists?
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-they potentiate anticholinergics
-must be avoided with MAOI's (they exacerbate the anticholinergic effects) - metabolized by CYP450 |
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What are the adverse effects of H1 receptor antagonists?
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- sedation
- dry mouth - upset stomach - overdose - can enter the breast milk and cross the placenta |
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What are the signs/symptoms of overdose of H1 receptor antagonists?
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- hallucinations
- ataxia - convulsions - arrhythmia - coma |
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What are the second generation H1 receptor antagonists?
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- Acrivastine
- Cetirizine - Desloratadine - Fexofenadine - Loratadine |
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What are H2 receptor antagonistsused for?
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- to reduce gastric acid production
- in the treatment of gastric ulcers and GERD |
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What are the H2 receptor antagonists?
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- Cimetidine
- Famotidine - Nizatidine - Ranitidine |
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What are the adverse effects of H2 receptor antagonists?
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- headache
- dizziness - diarrhea |
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________ inhibits CYP450 metabolism.
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Cimetidine
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________ does not interact with CYP450.
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Famotidine
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H2 receptor antagonists inhibit the first pass metabolism of ______.
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alcohol
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H2 receptor antagonists inhibit absorption of drugs favoring _______ environment. (such as _________)
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acidic environment
(ketoconazole) |
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What are the Mast cell stablizers?
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- Cromolyn sodium
- Nedocromil |
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What do the Mast cell stablizers do?
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They prevent the release of histamine from mast cells.
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What are the Mast cell stablizers used for?
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treatment of asthma (prophylactic) and allergic rhinitis
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What are the side effects of Mast cell stablizers?
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- cough
- bitter taste |
