Exam 2 Stoetling's Book Barbiturates questions

Question 1

What is the mechanism of action of barbiturates?
a) They activate GABAA receptors directly
b) They decrease glutamate activity
c) They increase the affinity of GABA for its binding site and activate chloride channels
d) They activate adenosine receptors

Answer 1

Answer: c) They increase the affinity of GABA for its binding site and activate chloride channels

Question 2

What is the role of β3 subunits in the activity of pentobarbital?
a) They are responsible for the immobilizing activity
b) They are responsible for the hypnotic activity
c) They are responsible for both the immobilizing and hypnotic activity
d) They have no role in the activity of pentobarbital

Answer 2

Answer: c) They are responsible for both the immobilizing and hypnotic activity

Question 3

Besides GABAA receptors, which other receptors do barbiturates act on?
a) Dopamine and serotonin receptors
b) Glutamate, adenosine, and neuronal nicotinic acetylcholine receptors
c) Norepinephrine and histamine receptors
d) Cannabinoid and opioid receptors

Answer 3

Answer: b) Glutamate, adenosine, and neuronal nicotinic acetylcholine receptors

Question 4

What is the effect of barbiturates on GABAA-activated opening of chloride channels?
a) They decrease the duration of the opening
b) They have no effect on the opening
c) They increase the duration of the opening
d) They block the opening completely

Answer 4

Answer: c) They increase the duration of the opening

Question 5

At what doses do barbiturates mimic the action of GABA?
a) Clinically used concentrations
b) Low doses
c) High doses
d) They do not mimic the action of GABA

Answer 5

Answer: c) High doses

Question 6

What is the basis for the short action of thiopental?
a. Rapid metabolism
b. Slow uptake
c. Slow redistribution
d. Slow elimination

Answer 6

Answer: b. Slow redistribution

Question 7

What is the time required for the plasma concentration of thiopental to decrease 50% after discontinuation of a prolonged infusion called?
a. Elimination half-life
b. Context-sensitive half-time
c. Hepatic extraction ratio
d. Reserve capacity

Answer 7

Answer: b. Context-sensitive half-time

Question 8

How is thiopental eliminated from the body?
a. Mostly through urine
b. Mostly through feces
c. Mostly through metabolism
d. Mostly through redistribution

Answer 8

Answer: c. Mostly through metabolism

Question 9

How does hepatic dysfunction affect the duration of action of thiopental?
a. It shortens the duration of action
b. It lengthens the duration of action
c. It has no effect on the duration of action
d. It depends on the type of dysfunction

Answer 9

Answer: b. It lengthens the duration of action

Question 10

What is the advantage of using benzodiazepines over barbiturates for preanesthetic medication?
a. Longer-lasting effects
b. Faster onset of action
c. More specific site of action
d. Less hangover effect

Answer 10

Answer: c. More specific site of action

Question 11

What is the relative potency of methohexital compared to thiopental for IV induction of anesthesia?
A. Methohexital is 1, thiopental is 1.1
B. Methohexital is 2.5, thiopental is 1
C. Methohexital is 1.1, thiopental is 2.5
D. Methohexital is 76%, thiopental is 61%

Answer 11

Answer: B. Methohexital is 2.5, thiopental is 1

Question 12

Which of the following is true about the direct effects of barbiturates used for IV induction of anesthesia?
A. They have no effect on skeletal, cardiac, or smooth muscles
B. They can cause involuntary skeletal muscle movements
C. They can decrease cardiac output
D. They have anticonvulsant effects

Answer 12

Answer: A. They have no effect on skeletal, cardiac, or smooth muscles

Question 13

What is the principal disadvantage of using methohexital for IV induction of anesthesia?
A. It has a longer context-sensitive half-time than thiopental
B. It can cause involuntary skeletal muscle movements
C. It has anticonvulsant effects
D. It increases the incidence of nausea

Answer 13

Answer: B. It can cause involuntary skeletal muscle movements

Question 14

What is the advantage of using methohexital for induction of anesthesia in patients with psychomotor epilepsy?
A. It has a longer context-sensitive half-time than thiopental
B. It has a greater effect on lowering the seizure threshold
C. It has fewer side effects than thiopental
D. It has a shorter recovery period than thiopental

Answer 14

Answer: B. It has a greater effect on lowering the seizure threshold

Question 15

Which drug has replaced barbiturates for induction of anesthesia in most cases?
A. Thiopental
B. Methohexital
C. Propofol
D. Opioids

Answer 15

Answer: C. Propofol

Question 16

What is the purpose of administering barbiturates in the treatment of increased intracranial pressure?
A. To increase cerebral blood volume
B. To decrease cerebral blood flow
C. To induce anesthesia
D. To improve brain survival after global cerebral ischemia

Answer 16

Answer: B

Question 17

How does thiopental affect cerebral blood flow and perfusion-to-metabolism ratio?
A. It increases both
B. It decreases both
C. It increases cerebral blood flow but decreases perfusion-to-metabolism ratio
D. It decreases cerebral blood flow but increases perfusion-to-metabolism ratio

Answer 17

Answer: B

Question 18

What is the maximum barbiturate-induced depression of CMRO2 that results in an isoelectric EEG?
A. 33%
B. 44%
C. 55%
D. 66%

Answer 18

Answer: C

Question 19

What is a potential side effect of barbiturate therapy for increased intracranial pressure?
A. Hypertension
B. Hypotension
C. Tachycardia
D. Bradycardia

Answer 19

Answer: B

Question 20

What is the efficacy of barbiturate therapy for improving outcome after head trauma?
A. Demonstrated
B. Not demonstrated
C. Inconclusive
D. Harmful

Answer 20

Answer: B

Question 21

In what situation has barbiturate therapy been shown to improve outcome for cerebral ischemia?
A. Global cerebral ischemia due to cardiac arrest
B. Focal cerebral ischemia that permits drug-induced metabolic suppression
C. Both A and B
D. Neither A nor B

Answer 21

Answer: B

Question 22

What is the recommended therapy for neuroprotection during cardiac surgery or after stroke?
A. Barbiturates
B. Hypothermia
C. Anticoagulants
D. Steroids

Answer 22

Answer: B