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103.
A 36-year-old male has been experiencing intense pressure to be more productive at work. This has resulted in his becoming extremely anxious, which makes it very difficult for him to function effectively. He wishes to keep his job. Physical examination and blood chemistries are normal. He is given diazepam, which diminishes his anxiety and allows him to concentrate on his work. What is the mechanism of action of diazepam?
A.
It directly opens the Cl- channel of the GABA receptor
B.
It increases the frequency of opening of the Cl- channel of the GABA receptor
C.
It prolongs the duration of opening of the Cl- channel of the GABA receptor



104.
Which best describes the mechanism of interaction of cimetidine with benzodiazepine?
A.
It decreases benzodiazepine's metabolism
B.
It decreases benzodiazepine's sensitivity at the site of action
C.
It decreases benzodiazepine's renal excretion
D.
It decreases benzodiazepine's plasma protein binding
E.
It decreases benzodiazepine's intestinal absorption

103 b
104 a

103b, 104a

b, a

103 B

104 A.

103.
A 36-year-old male has been experiencing intense pressure to be more productive at work. This has resulted in his becoming extremely anxious, which makes it very difficult for him to function effectively. He wishes to keep his job. Physical examination and blood chemistries are normal. He is given diazepam, which diminishes his anxiety and allows him to concentrate on his work. What is the mechanism of action of diazepam?
A.
It directly opens the Cl- channel of the GABA receptor
B.
It increases the frequency of opening of the Cl- channel of the GABA receptor
C.
It prolongs the duration of opening of the Cl- channel of the GABA receptor

The answer is: B

Benzodiazepines, such as diazepam, bind to the GABA receptor/ion channel complex, enhancing GABA-induced Cl- currents related to more frequent bursts of Cl- channel opening by GABA.

104.
Which best describes the mechanism of interaction of cimetidine with benzodiazepine?
A.
It decreases benzodiazepine's metabolism
B.
It decreases benzodiazepine's sensitivity at the site of action
C.
It decreases benzodiazepine's renal excretion
D.
It decreases benzodiazepine's plasma protein binding
E.
It decreases benzodiazepine's intestinal absorption


The answer is: A

Cimetidine inhibits the activity of cytochrome P450, slowing benzodiazepam metabolism.