Medical Pharmacology Practice Questions: Histamine Pharmacology

Contemporary H1 receptor blockers are best categorized as:
1. Pure antagonists
2. Partial agonists
3. Inverse agonists
4. Agonists
Histamine H1 receptor blockers:
1. Compete with histamine
2. Decrease receptor mediated constitutive activity
3. Both
4. Neither
Example(s) of H1-type histamine receptor blockers:
1. Chlorpheniramine
2. Diphenhydramine
3. Pyrilamine
4. A & B
5. B & C
6. A & C
7. A, B & C
Which one of the following H1-histamine receptor antagonists is classified as a phenothiazine?
1. Loratadine
2. Chlorcyclizine
3. Promethazine
4. None of the above
H1-histamine receptor blockers:
1. Block histamine effects on smooth muscle
2. Antagonize histamine vasoconstrictor activity
3. Both
4. Neither
Histamine-induced increases in capillary permeability with subsequent edema and wheal are effectively inhibited by H1 blockers.
1. True
2. False
H1 antagonists, comparable to H2 antagonists, decrease gastric secretion albeit to a lesser extent.
1. True
2. False
Many H1 receptor antagonists may reduce secretion in:
1. Glands with cholinergic innervation
2. The respiratory tree
3. Both
4. Neither
Histamine represents one potent autocoid released during hypersensitivity reactions. H1 receptor blockers may variably protect against some of the consequences of hypersensitivity reactions.
1. True
2. False
Overdose due to H1-histamine receptor blockers may manifest as central excitation, such as convulsions, noted especially in infants.
1. True
2. False