anxiolytics and sedative-hypnotic drugs Flashcards

1
Q

3 types of anxiety disorders

A

generalised anxiety - persistent and excessive anxiety
panic disorder - attacks of overwhelmed fear with marked somatic symptoms (sweating, tachycardia, chest pains etc.)
social anxiety disorder (social phobia) - fearful and anxious about social interactions an situations that may be subject to scrutiny

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2
Q

GABAa receptor

A

19 subunits
native GABAa receptors - two a subunits, two b subunits and one subunit of a third type (usually gamma)
distinct pharmacological profiles and physiological roles

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3
Q

GABA

A

the primary inhibitory neurotransmitter in the brain

binds to the GABAa receptor at the interface of a/b subunits

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4
Q

BZD binds at

A

interface of alpha and gamma subunit in GABAa receptor

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5
Q

benzo diazepine side effects - a2 subunit mediated

A

anxiolytic effects -
short acting drugs may paradoxically increase aggression due to withdrawal syndromes
muscle relaxant effects - act through the GABAa receptor in the spinal cord, facilitates anxiolytic effects (increased muscle tone is common to anxiety)

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6
Q

BZD side effects - a1 subunit mediated

A

hypnotic and sedative side effects - decrease sleep latency and increase sleep duration, short acting preferred, long acting drugs lead to drowsiness
anticonvulsant effects
anterograde amnesia - prevent memory of events experienced under influence of drugs, can also be a5-mediated

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7
Q

BZD chemical structure

A

seven membered ring fused to an aromatic ring
positive allosteric modulator - binds to BZD site at interface of a/y, increasing affinity for GABA and the frequency of channel opening, producing greater inhibitory effect on the target neuron

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8
Q

four BZDs

A

midazolam, alprazolam, diazepam, oxazepam

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9
Q

why is BZD a PAM

A

positive allosteric modulator - binds to a different site than GABA but increases affinity for GABA

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10
Q

midazolam

A

ultra short acting
produces minor active metabolites
hypnotic, anaesthetic and anticonvulsant

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11
Q

short acting BZD

A

oxazepam

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12
Q

oxazepam

A

short acting
no active metabolites
anxiolytic, hypnotic

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13
Q

medium acting BZD

A

alprazolam

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14
Q

long acting BZD

A

diazepam

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15
Q

alprazolam

A

active metabolites
anxiolytic
medium acting

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16
Q

diazepam

A

long actiing
active metabolites
anxiolytic, muscle relaxant, anticonvulsant

17
Q

drug administration of BZD

A

oral (common, IV or rectal
good oral absorbtion and bioavailability
fast onset (30-60 minutes) of therapeutic effects

18
Q

BZD used for

A

acute anxiety
behavioural emergencies
premedication for surgery and procedures

19
Q

undesribale effects of BZD

A

drowsiness, amnesia, and impaired coordination

20
Q

short acting drugs are

A

hypnotics

21
Q

long acting drugs are

A

anxiolytics

22
Q

diazepam in older patients

A

drug metabolism by cytochrome P450
significant impact of aging on drug metabolism
has active metabolites

23
Q

oxazepam in elderly patients

A

drug metabolism by glucuronidation, relatively minor effect of aging on drug emtabolism
does not form active metabolites

24
Q

drug drug interactions with BZD

A

eg. coadministration of diazepam and fluvoxamine (an SSRI)

diazepam uses CYP2C19 and flluvoxamine is a CYP2C19 inhibitor

25
Q

tolerance in BZD

A

develops due to continued use
decrease in therapeutic effects when given the same dose
use for <2 weeks

26
Q

withdrawal symptoms in BXD

A

on cessation of use
rebound anxiety, tremor, sleep disturbance, loss of appetite
short acting drugs are more problematic

27
Q

acute overdose of BZD

A

relatively safe
treated with IV flumazenil (compete with benzodiazepines for the binding site)
if combined with other CNS depressants (alcohol or opioids) - severe respiratory depression

28
Q

flumazenil

A

used to treat BZD overdose
competed with BZD for binding site
short duration of action
for long acting BZD overuse - may require multiple flumazenil injections

29
Q

buspirone

A

5-HT1a receptor partial agonist
delayed anxiolytic effect
less problematic than benozdiazepines (no sedation or impaired motor control, no tolerance or withdrawal)
effective for generalised anxiety

30
Q

side effects of buspirone

A

nausea, dizziness, headache and restlessness
does not cause sedation or impared notor coordination
does not lead to tolerance or withdrawal effects

31
Q

antidepressants

A

SSRIs are preferred due to better side effect profile
delayed anxiolytic effects
reduce depression associated with anxiety
does not produce hypnotic effect
effective for generalised and socialised anxiety disorder

32
Q

transient insomnia

A

shift work, jet lag

33
Q

short term insomnia

A

experience emotional or stressful events

34
Q

chronic insomnia

A

underlying conditions (eg. anxiety, depression, drug abuse)

35
Q

BZD for insomnia

A

a1 subunit-mediated hypnotic effects

  • decrease sleep latency and increase sleep duration
  • improved sleeping quality while on treatment but rebound worsening of sleep
  • short term use ( <2 weeks)
36
Q

Z-drugs

A

zolpidem, zaleplon, and eszopiclone
structurally distinct from benzodiazepines but share the same binding site
a1-selective - hypnotic effects, short acting
lacks appreciable anxiolytic activity

37
Q

adverse effects of Z-drugs

A

similar to benzodiazepines
short-term use to avoid tolerance and dependance
reports of bizarre behaviours and falls - use with caution, particularly in elderly patients
overdose - treated with flumazenil
more dangerous when combined with other CNS depressants

38
Q

3 Z-drugs examples

A

zolpidem, zaleplon, eszopiclone