Benzodiazepines (Exam I) Flashcards
Differentiate sedatives and hypnotics.
- Sedatives: induce calm/sleep
- Hypnotics: induce hypnosis/sleep
When is anesthesia awareness most common?
What are the rates of this occurring?
- During sedation cases and during emergence.
- 1:1000 (or 1:10,000 per some studies)
What is the mechanism for less EEG activity seen during anesthesia/sedation?
- Less cerebral blood flow (CBF) and cerebral metabolic requirement of oxygen (CMRO₂) = less metabolism = less EEG activity.
What was the first compressed EEG?
Give the details of the study exploring its use.
- Bispectral analysis
- 1500 subjects w/ 5000 hours of EEG signaling
What drugs were utilized in the bispectral analysis study?
- Isoflurane/ O₂
- Propofol/nitrous
- Propofol/alfentanil
Which drugs exhibit a strong correlation between BIS change and patient movement?
Which drugs do not exhibit this correlation?
- Hypnotic drugs
- Narcotics
In the BIS study, what reading indicated that a patient was for sure unconscious?
- <58
In the BIS study, a reading of <65 indicated a ___% of return to consciousness within the minute.
- 5%
What is a normal BIS range?
- 40-60
What are the four parameters (other than the BIS itself) noted on a BIS monitor?
- SQI
- EMG
- EEG
- SR
What is the SR noted on a BIS monitor?
What would an SR of 60 indicate?
- Suppression Ratio (how many seconds per minute that the EEG is flat)
- SR of 60 means EEG is completely flat (could be brain death).
Name drugs that could suppress EEG activity.
- Hypnotics, volatiles, NMBDs, Opioids
- β-blockers
Name drugs that could enhance EEG activity.
- Ketamine, epinephrine
What are the five main functions of a benzodiazepine?
- Anxiolysis
- Sedation
- Anterograde amnesia
- Anticonvulsant
- Spinal-cord mediated muscle relaxation
What is the only “thing” that can cause retrograde amnesia?
- ECT (electroconvulsive therapy)
Why are written instructions given to a patient after waking up from benzodiazepine sedation?
- Anterograde amnesia effects last longer than sedative effects.
Can benzodiazepines be substituted for NMBs due to their spinal-cord mediated skeletal muscle relaxation?
- No; not adequate for true paralysis
__________ drugs can induce CYP450’s.
Barbiturates
What is the mechanism of action of benzodiazepines?
- Enhancement of GABA binding by changing receptor affinity. Allows for greater Cl⁻ influx and thus hyperpolarization.
Which GABA site do benzodiazepines bind to?
- Trick question. Benzo’s do not bind directly to GABA sites.
How many subunits are present in a GABA receptor?
Where do GABA molecules bind on said receptor?
- Five
- In-between the α1 & β2 subunits.
What subunits do Benzodiazepines bind to on the GABA receptor?
- In-between α1 & γ2
GABA receptors with α1 subunits exhibit what properties when bound?
How abundant are these specific receptors and where are they found?
- Sedation, amnesia, & anticonvulsion
- Most abundant: cerebral cortex, cerebellar cortex, & thalamus.
GABA receptors with α2 subunits exhibit what properties when bound?
How abundant are these specific receptors and where are they found?
- Anxiolysis & skeletal muscle relaxation
- Less abundant: hippocampus & amygdala
What other drugs bind to GABA receptors besides benzodiazepines?
What is the result if one of these drugs is given in conjunction with benzodiazepines?
- Barbiturates, Etomidate, Propofol, & EtOH
- Risk of overdose & cross-tolerance
Benzodiazepines are highly _____ soluble and highly _______ bound.
- Lipid; protein
What factors cause differing effects amongst benzodiazepines?
- Potency
- Lipid solubility
- Redistribution (to peripheral tissues)
- Pharmacokinetics
List EEG waves from greatest activity to least activity.
- Gamma → Βeta → Αlpha → Theta → Delta
What general effect(s) do benzodiazepines have on EEG activity?
- Decreased αlpha activity
What platelet effects do benzodiazepines have?
- Inhibitory towards platelet aggregation (very slight, only in vitro studies)