PreOp Meds: Benzodiazepine

Question 1

What are the five main functions of a benzodiazepine?

Answer 1

• Anxiolysis
• Sedation
• Anterograde amnesia
• Anticonvulsant
• Spinal-cord mediated muscle relaxation

Question 2

What is the only “thing” that can cause retrograde amnesia?

Answer 2

• ECT (electroconvulsive therapy)

Question 3

Why are written instructions given to a patient after waking up from benzodiazepine sedation?

Answer 3

• Anterograde amnesia effects last longer than sedative effects.

Question 4

Can benzodiazepines be substituted for NMBs due to their spinal-cord mediated skeletal muscle relaxation?

Answer 4

• No; not adequate for true paralysis

Question 5

__________ drugs can induce CYP450’s.

Answer 5

Barbiturates

Question 6

What is the mechanism of action of benzodiazepines?

Answer 6

• Enhancement of GABA binding by changing receptor affinity. Allows for greater Cl⁻ influx and thus hyperpolarization.

Question 7

Which GABA site do benzodiazepines bind to?

Answer 7

• Trick question. Benzo’s do not bind directly to GABA sites.

Question 8

How many subunits are present in a GABA receptor?
Where do GABA molecules bind on said receptor?

Answer 8

• Five
• In-between the α1 & β2 subunits.

Question 9

What subunits do Benzodiazepines bind to on the GABA receptor?

Answer 9

• In-between α1 & γ2

Question 10

GABA receptors with α1 subunits exhibit what properties when bound?
How abundant are these specific receptors and where are they found?

Answer 10

• Sedation, amnesia, & anticonvulsion
• Most abundant: cerebral cortex, cerebellar cortex, & thalamus.

Question 11

GABA receptors with α2 subunits exhibit what properties when bound?
How abundant are these specific receptors and where are they found?

Answer 11

• Anxiolysis & skeletal muscle relaxation
• Less abundant: hippocampus & amygdala

Question 12

What other drugs bind to GABA receptors besides benzodiazepines?
What is the result if one of these drugs is given in conjunction with benzodiazepines?

Answer 12

• Barbiturates, Etomidate, Propofol, & EtOH
• Risk of overdose & cross-tolerance

Question 13

Benzodiazepines are highly _____ soluble and highly _______ bound.

Answer 13

• Lipid; protein

Question 14

What factors cause differing effects amongst benzodiazepines?

Answer 14

• Potency
• Lipid solubility
• Redistribution (to peripheral tissues)
• Pharmacokinetics

Question 15

List EEG waves from greatest activity to least activity.

Answer 15

• Gamma → Βeta → Αlpha → Theta → Delta

Question 16

What general effect(s) do benzodiazepines have on EEG activity?

Answer 16

• Decreased αlpha activity

Question 17

What platelet effects do benzodiazepines have?

Answer 17

• Inhibitory towards platelet aggregation (very slight, only in vitro studies)