Benzodiazepines Flashcards

(90 cards)

1
Q

what receptor do benzodiazepines bind to

A

GABA-A ligand-gated chloride channel complex

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2
Q

what is the mechanism of action of benzodiazepines

A

binds to GABA-A–> enhances the inhibitory effects of GABA-regulated channels

INHIBITS neuronal activity presumably in AMYGDALA-centered fear circuits to provide therapeutic benefits in anxiety disorders

inhibitory actions in CEREBRAL CORTEX may provide therapeutic benefits in seizure disorders

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3
Q

how many GABA receptor subtypes are there

A

3–> A, B, C

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4
Q

what is the function of the GABA-A receptor subtype

A

gatekeeper for the chloride channel–> chloride goes into the cell, polarizing the action potential AWAY from activation

action is inihibitory in the amygdala and frontal cortex

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5
Q

the GABA-A receptor is allosterically modulated by which compounds

A

benzos

alcohol

Z drugs

barbiturates

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6
Q

list the four MAIN indications for benzodiazepines

A

anxiety disorder

anxiety disorder associated with depressive symptoms

initial treatment of status epilepticus (

preanesthetic

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7
Q

list other indications for benzodiazepines

A

insomnia

muscle spasm

alcohol withdrawal psychosis

headache

panic disorder

acute mania (adj)

acute psychosis (adj)

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8
Q

how quickly might someone notice benefit from benzodiazepines

A

some immediate relief with first dosing is common

can take several weeks for maximal therapeutic benefit with daily dosing

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9
Q

what is the usual starting dose and the typical range of the following benzodiazepine:

lorazepam

A

start–> 0.5mg

typical daily dosing–> 1-2mg /day

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10
Q

what is the usual starting dose and the typical range of the following benzodiazepine:

clonazepam

A

start–> 0.5mg

typical daily dosing–> 0.5-2mg /day

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11
Q

what is the usual starting dose and the typical range of the following benzodiazepine:

diazepam

A

start–> 2-10 mg

typical daily dosing –> 4-40mg/day

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12
Q

can you use benzodiazepines if kidney/liver function is present

A

monitor functioning if impairment is present

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13
Q

list common side effects of benzodiazepines

A

sedation

fatigue

depression

decreased cognitive processing

anterograde amnesia

dizziness

ataxia/visuospatial and visuomotor deficits

slurred speech

weakness

tolerance/dependence

rebound anxiety

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14
Q

in which patients should you not prescribe benzodiazepines (non-psychiatric reason)

A

those with occupational risks i.e truck drivers, pilots–> higher likelihood of crashes (OR 1.6 on any benzo)

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15
Q

list rare side effects from benzodiazepines

A

hallucinations

hypotension

paradoxical agitation

respiratory depression (esp. when Rx along with CNS depressants)

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16
Q

what medication can counter benzodiazepine overdose

A

flumazenil

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17
Q

what does benzodiazepine overdose look like

A

hypotension

rare respiratory depression

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18
Q

in which patients is the risk of tolerance/dependence to benzodiazepines higher

A

treatment periods over 12 weeks

those with polysubstance abuse

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19
Q

what CYP interactions does the following medication have:

lorazepam

A

none

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20
Q

what CYP interactions does the following medication have:

clonazepam

A

3A4 (major substrate)

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21
Q

what CYP interactions does the following medication have:

diazepam

A

3A4 (major substrate), 2C19 (major substrate)

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22
Q

is lorazepam safe in end stage kidney disease

A

no–> not recommended

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23
Q

which benzo should be used with caution in liver impairment

A

diazepam

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24
Q

what is the half life of lorazepam

A

10-20 hours

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25
what is the half life of clonazepam
30-40 hours
26
what is the half life of diazepam
20-50 hours
27
what determines duration of action in benzodiazepines
distribution (not as much by elimination half life) --> ie diazepam has long half life but is highly lipid soluble so actually has relatively SHORT duration of action as will distribute fairly quickly marked inter-individual variation
28
how are benzos metabolized
hepatic oxidation, reduction and conjugation
29
how long will someone notice benefits for insomnia from benzos
about 14 days
30
what is the risk of rapid withdrawal of benzodiazepines
seizure
31
what is the recommended tapering protocol to get someone off benzos if they have been on them a long time
rec. taper length is 6-12 months (10% per month) first half of taper usually much easier than second half
32
list 3 of the strongest predictors of benzo withdrawal severity
1. high baseline neuroticism 2. female sex 3. mild to mod alcohol use *these are more predictive than daily dose or half life of the benzo
33
you should evaluate patient for what medical disorder before prescribign benzos
OSA--> benzos can worsen OSA
34
how might you reconsider benzo use in the pediatric population
lower dosing range higher risk of SEs (same for geri)
35
which benzo is NOT recommended for use during pregnancy
lorazepam--> especially during first trimester
36
what are some of the considerations for benzo use during pregnancy
possible increased risk of birth defects when benzos taken during pregnancy infants whose mothers received benzos late in pregnancy may experience withdrawal effects neonatal FLACCIDITY has been reported in mothers who took benzo during pregnancy some drug found in mother's breast milk effects on infant that have been observed: feeding difficulties, sedation, weight loss *risk category D--> positive evidence of risk to human fetus/ benefits may still justify use
37
list indications for clonazepam
REM sleep behaviour disorder akathesia 2nd line panic disorder and GAD
38
how quickly does clonazepam act
slow onset
39
list indications for lorazepam
EtOH/benzo withdrawal akathesia agitation seizure catatonia 2nd line panic disorder and GAD
40
which benzos can be given IM
lorazepam and midazolam
41
how is lorazepam excreted
renally--> so does not accumulate in liver failure (same as oxazepam and temazepam)
42
how quickly does lorazepam act
intermediate onset
43
indications for alprazolam
2nd line panic disorder and GAD
44
how quickly does alprazolam act
intermediate onset
45
what is the max dose for lorazepam
10mg/day 30mg/day in catatonia
46
what is the max dose of alprazolam per day
8mg/day
47
what is the max dose of diazepam per day
40m /day
48
what is the max dose of clonazepam per day
4mg/day
49
indications for diazepam
EtOH/benzo withdrawal 2nd line panic disorder
50
how quickly does diazepam work
rapid onset *careful in liver failure (increases half life from 50 hours to 500 hours)
51
what is the starting dose of midazolam
0.2mg/kg
52
indications for midazolam
anesthesia palliative sedation seizure
53
how quickly does midazolam work? what is its half life?
very rapid onset half life 3 hours
54
what is the max daily dose of chlordiazepoxide
300mg/day (start at 25mg)
55
indications for chlordiazepoxide
mild to mod EtOH benzo withdrawal
56
what receptor does zopiclone/zolpidem act on
GABA-A receptor
57
what is the starting dose and max dose of zopiclone
start 3.75mg max 7.5 mg
58
what are the starting and max doses of zolpidem
start 5-6.25mg max 10mg
59
side effects for zolpidem
complex sleep behaviours sedation nausea headache
60
side effects for zopiclone
sedation headache nausea
61
how do the Z drugs affect sleep
reduce sleep latency
62
what is sodium oxybate
a GHB and GABA-B receptor agonist
63
what are indications for sodium oxybate
daytime sleepiness and cataplexy caused by narcolepsy
64
indications for Z drugs
insomnia
65
side effects of sodium oxybate
confusion N/V sedation edema respiratory depression psychosis suicidality
66
what general effects do benzodiazepines have
sedative-hypnotic anxiolytic anticonvulsant muscle relaxant
67
describe benzodiazepine protein binding affinity
70-909% protein bound *but distribute RAPIDLY to CNS
68
how do benzodiazepines cross the blood brain barrier
via passive diffusion therefore, rate of CNS distribution correlates with lipophilicity
69
which are the two most lipophilic benzodiazepines
diazepam and midazolam thus have fastest onset of action
70
list 3 benzodiazepines that do not go through CPY450 metabolism
lorazepam oxazepam temazepam "the LOT benzos"
71
which benzos are metabolized through glucoronidation
the LOT benzodiazepines (loraz, oxaz, temaz) we care because glucoronidation is better preserved in liver failure so these benzodiazepines are better for liver failure
72
are benzodiazepines agonists?
technically no--> they are positive allosteric modulators (PAMs) which act on GABA-A
73
apart from GABA-A, where else does clonazepam act
partial serotonin agonist
74
what are the "ATOM" benzos
Alprazolam Triazolam Oxazepam Midazolam
75
what do the ATOM benzos have in common
all have rapid onset and are short acting increases risk of abuse, misuse, addiction
76
how long does it take for tolerance and withdrawal to develop on benzos
minimum 4 weeks treatment *psychological dependence can develop at any point during treatment
77
why should you be careful prescribing benzos to the elderly
significantly increases risk for confusion, delirium, cognitive impairment in the elderly
78
how do benzos cause respiratory depression
two actions: 1. depress central respiratory drive and chemoreceptor responsiveness to hypercapnia 2. midaz has been shown to depress the hypoxic ventilatory response
79
how do benzos affect REM sleep
decreases amount of REM sleep
80
what is the typical benzo taper
10-20% every 1-2 weeks
81
what common antidepressants affect metabolism of some benzos
fluoxetine, fluvoxamine, sertraline decrease metabolism and increase plasma levels of benzos metabolized by the CYP system (i.e alprazolam... any of them but the LOT benzos)
82
how quickly does benzo withdrawal begin after cessation of the agent
depends on the agent i.e short acting benzos like triazolam may precipitate withdrawal within hours after being stopped
83
how quickly might lorazepam withdrawal develop
can develop within 6-8 hours of med cessation will peak in intensity on second day and improve by day 4-5
84
when might diazepam withdrawal syndrome start
has long acting metabolites and thus may not produce withdrawal symptoms for 1-2 days (or up to a week) and sx may not peak until the second week after med discontinuation
85
can benzo withdrawal be life threatening
yes--similar to EtOH withdrawal can progress to a life threatening delirium
86
list risk factors for benzo withdrawal syndrome
longer substance use higher dosages -----> these factors increase risk for severe withdrawal i.e doses of diazepam 40mg or more are more likely to produce withdrawal symptoms doses of diazepam 100mg or above are more likely to be followed by withdrawal seizures or delirium *note that withdrawal has also been reported with low doses when taken daily for several months
87
list symptoms of benzo withdrawal
autonomic hyperactivity (sweating, pulse above 100) hand tremor insomnia N/V transient visual/tactile/auditory hallucinations or illusions psychomotor agitation anxiety grand mal seizures
88
what % of people undergoing UNtreated benzo withdrawal will have a grand mal seizure
20-30%
89
what tools can be used to monitor benzo withdrawal
CIWA-Ar or PAWSS (same as alcohol)
90
what is thought to be the pathophysiology behind benzo withdrawal symptoms
imbalance between GABA (decreased) and glutamate (increased)