Exam 2 Stoetling's Book Barbiturates questions Flashcards
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: c) They increase the affinity of GABA for its binding site and activate chloride channels
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: c) They are responsible for both the immobilizing and hypnotic activity
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: b) Glutamate, adenosine, and neuronal nicotinic acetylcholine receptors
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: c) They increase the duration of the opening
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: c) High doses
What is the basis for the short action of thiopental?
a. Rapid metabolism
b. Slow uptake
c. Slow redistribution
d. Slow elimination
Answer: b. Slow redistribution
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: b. Context-sensitive half-time
How is thiopental eliminated from the body?
a. Mostly through urine
b. Mostly through feces
c. Mostly through metabolism
d. Mostly through redistribution
Answer: c. Mostly through metabolism
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: b. It lengthens the duration of action
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: c. More specific site of action
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: B. Methohexital is 2.5, thiopental is 1
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: A. They have no effect on skeletal, cardiac, or smooth muscles
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: B. It can cause involuntary skeletal muscle movements
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: B. It has a greater effect on lowering the seizure threshold
Which drug has replaced barbiturates for induction of anesthesia in most cases?
A. Thiopental
B. Methohexital
C. Propofol
D. Opioids
Answer: C. Propofol
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: B
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: B
What is the maximum barbiturate-induced depression of CMRO2 that results in an isoelectric EEG?
A. 33%
B. 44%
C. 55%
D. 66%
Answer: C
What is a potential side effect of barbiturate therapy for increased intracranial pressure?
A. Hypertension
B. Hypotension
C. Tachycardia
D. Bradycardia
Answer: B
What is the efficacy of barbiturate therapy for improving outcome after head trauma?
A. Demonstrated
B. Not demonstrated
C. Inconclusive
D. Harmful
Answer: B
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: B
What is the recommended therapy for neuroprotection during cardiac surgery or after stroke?
A. Barbiturates
B. Hypothermia
C. Anticoagulants
D. Steroids
Answer: B
