LT Pharma: Antihistamine Flashcards
How many types of histamine receptors are known to mediate the effects of histamine?
a) Two
b) Four
c) Six
d) Eight
b) Four
(H1, H2, H3, and H4 receptors)
How is histamine synthesized in the body?
a) From the amino acid lysine
b) From the amino acid histidine by histidine decarboxylase
c) From the amino acid tryptophan
d) From the amino acid glutamine
b) From the amino acid histidine by histidine decarboxylase
Where is histamine primarily stored in the body?
a) Lymph nodes
b) Liver
c) Granules within mast cells and basophils
d) Kidneys
c) Granules within mast cells and basophils
Histamine is found in most tissues, particularly the?
Lungs, skin, & GI
H1 receptor locations & their corresponding functions?
(4 mentioned)
H2 receptor locations & their corresponding functions?
(2 were mentioned)
- Cardiac muscles → Cardiac stimulation
- Parietal cells of stomach → Stimulates gastric acid secretion
H3 receptor location & its corresponding function?
(1 was mentioned)
Presynaptic neurons → Inhibit neurotransmitter release
H4 receptor locations & their corresponding functions?
(1 was mentioned)
Mast cells & eosinophils → Stimulation of chemotaxis
What triggers the release of histamine from mast cells during inflammatory or allergic reactions?
a) Direct interaction with complement fragments C3a and C5a
b) Direct interaction with IgG antibodies
c) Interaction of an antigen with IgE bound to sensitized mast cells and basophils
d) Direct interaction with histamine receptors
c) Interaction of an antigen with IgE bound to sensitized mast cells and basophils
In addition to inflammatory or allergic reactions, what other mechanisms can lead to the release of histamine?
a) Interaction with IgA antibodies
b) Direct release by complement fragments C3a and C5a, as well as by some drugs
c) Interaction with IgM antibodies
d) Direct release by T lymphocytes
b) Direct release by complement fragments C3a and C5a, as well as by some drugs
Which drugs can cause the release of histamine?
d-tubocurarine or morphine
Key members of 1st generation Antihistamines?
diphenhydramine, chlorpheniramine, doxylamine, etc.
Key members of 2nd generation Antihistamines?
loratadine, desloratadine, cetirizine, fexofenadine.
mnemonic: lazy dogs carry fleas
The major pathological roles of histamine are in?
(3 were mentioned)
-
Allergic diseases
- allergic rhinitis (hay fever)
- allergic conjunctivitis
- asthma
- urticaria (both acute and chronic), etc. - Anaphylactic shock
- Hypersecretion of acid in peptic ulcers.
What is the primary MOA of antihistamines?
a) Inhibition of histamine formation
b) Blockade of histamine H1 receptors
c) Activation of histamine H2 receptors
d) Stimulation of histamine release
b) Blockade of histamine H1 receptors