Block 4 Lecture 4 -- Antipsychotics Flashcards

1
Q

What is the general MoA of FGAs?

A

competitive, postsynaptic ML system D2r antagonists

– induce time-dependent change in DA neurotransmission

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2
Q

What are the low potency FGAs?

A

1) chlorpromazine
2) prochlorperazine
3) thioridazine

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3
Q

What are the high potency FGAs?

A

1) fluphenazine
2) haloperidol
3) pimozide
4) thiothixine

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4
Q

What are the phases of FGAs effect on DA neurotransmission?

A

1) initial D2 blockade
2) continued D2 blockade
3) supersensitivity

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5
Q

What happens in the initial D2r blockade by FGAs?

A

compensatory response

– increased DA synthesis and release

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6
Q

What happens in the continued D2r blockade phase caused by FGAs?

A

1) inactivation of dopaminergic neurons
2) depolarization blockade
- - reduced DA release in ML and NS
- - reduced positive sxs

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7
Q

What happens in the supersensitivity phase of the D2 blockade caused by FGAs?

A

1) DAr upregulation
2) supersensitive to DAr agonsits
- - increased risk for tardive dyskinesia
- - weeks to develop
- - can be irreversible

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8
Q

ADRs of FGAs.

A

1) EPS
2) anticholinergic
3) anti-adrenergic
4) antihistaminergic
5) QT prolongation
6) metabolic syndrome
7) drug-induced seizures
8) neuroleptic malignant syndrome

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9
Q

What are the sxs associated with neuroleptic malignant syndrome?

A

SHACkA after 24-72 h

    • stiff (muscle rigidity)
    • hot (fever)
    • altered (mental status)
    • CK elevation
    • autonomic instability
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10
Q

How is neuroleptic malignant syndrome treated?

A

rare, potentially fatal

d/c drug x several weeks
– supportive treatment (dantrolene + bromocriptine)

change drug, titrate slowly to minimum dose

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11
Q

What are the drug interactions for FGAs?

A

1) smoking (decreased drug levels)
2) CNS depressants (potentiation)
- - no PPB displacement rxns
- - no significant effect on CYPs (exception: chlorpromazine and thioridazine, 2d6)

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12
Q

What are the antihistaminergic ADRs of FGAs?

A

due to H1 antagonism

    • weight gain
    • drowsiness
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13
Q

What are the antiadrenergic ADRs of FGAs?

A

due to a1 antagonism

    • orthostasis
    • reflex tachycardia
    • dizziness
    • drowsiness
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14
Q

What causes the anticholinergic ADRs of FGAs?

A

antagonism of M1

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15
Q

What are the EPS ADRs of FGAs?

A

caused by D1,2 antagonism

1) dystonia
2) akathisia
3) tremor/rigidity/bradykinesia
4) irreversible tardive dyskinesia
5) antiemetic
6) gynecomastia (males) and menstrual irregularity

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16
Q

What type of receptor is M1? a1? H1?

A

all Gq

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17
Q

What are special ADRs of chlorpromazine?

A

sedation
photosensitivity
jaundice

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18
Q

What is the t1/2 of chlorpromazine?

A

30+ hours

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19
Q

What are specific PK parameters for prochlorperazine?

A

t1/2 = 4-8 hrs

99% PPB

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20
Q

What is the t1/2 of thioridazine?

A

30 hours

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21
Q

What are significant ADRs of thioridazine?

A

very anticholinergic
very sedative
lower potential for EPS

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22
Q

What is the t1/2 of fluphenazine?

A

20+ hours

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23
Q

What are significant ADRs of fluphenazine?

A

significant EPS

a little sedation

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24
Q

What is the t1/2 of haloperidol?

A

24 hours

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25
Q

What are significant ADRs of haloperidol?

A

significant EPS

a little sedation

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26
Q

Which FGAs have additional indications?

A

pimozide only

    • Tourette’s
    • resistant tics
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27
Q

What is the t1/2 of pimozide?

A

55+ hours

28
Q

What is significant about thiothixine?

A

sulfonamide

35+ hours t1/2

29
Q

What is the general MoA of atypicals/SGAs?

A

competitive D2 and 5-HT receptor antagonists

30
Q

What are the SGAs/atypicals?

A

1) asenapine
2) iloperidone
3) lurasidone
4) olanzipine
5) quetiapine
6) risperidone
7) paliperidone
8) ziprasidone
9) clozapine
10) aripiprazole

31
Q

What are the general ADRs of SGAs?

A

1) weight gain
2) metabolic syndrome
- - myocarditis/ cardiomyopathy
3) QT prolongation
4) agranulocytosis
5) tardive dyskinesia

32
Q

PK notes for asenapine:

A

t1/2 = 24h
95% PPB
CYP1A2

33
Q

PK notes for iloperidone:

A

t1/2 = 18-33 h
95% PPB
CYP3A4 and 2D6

34
Q

PK notes for lurasidone:

A

t1/2 = 18h
9-19% Fpo increased by food
CYP3A4

35
Q

PK notes for olanzapine:

A

t1/2 = 33 hours

93% PPB

36
Q

PK notes for quetiapine:

A

t1/2 = 7 h (a. met 9-12h)
83% PPB
CYP3A4 + 2D6

37
Q

PK notes for risperidone:

A

t1/2 = 20 hours

CYP3A4

38
Q

PK notes for paliperidone:

A

t1/2 = 23 hours

renal excretion (adjust)

39
Q

PK notes for ziprasidone:

A

t1/2 = 7 hrs

40
Q

PK notes for clozapine:

A

t1/2 = 6-26 hours

41
Q

PK notes for aripiprazole:

A

t1/2 = 75+ hours
99% PPB
CYP3A4, 2D6

42
Q

Which atypicals are indicated for bipolar disorder?

A

1) lurasidone
2) quetiapine
3) risperidone
4) palperidone
5) ziprasidone
6) clozapine
7) aripiprazole

all “-dones” except Ilo-

43
Q

Which SGAs have other indications besides schizophrenia and bipolar disorder?

A

1) asenapine (acute mania)
2) risperidone (behavior problems in autism)
3) clozapine (borderline personality disorder, treatment-resistant schizophrenia)

44
Q

Which atypicals are sedative?

A

1) olanzapine

2) quetiapine

45
Q

Which atypicals are associated with weight gain?

A

1) olanzapine (25%!)
2) clozapine
3) risperidone

46
Q

ADRs of iloperidone?

A

orthostasis

47
Q

Counseling point for asenapine:

A

SL tabs

    • no chewing/crushing/swallowing
    • don’t eat/drink within 10 mins
48
Q

ADRs of risperidone:

A

1) weight gain
2) tardive dyskinesia
3) NMS
4) black box: increased mortality in patients with dementia (don’t use in elderly)

49
Q

Which atypicals can’t be used in dementia patients?

A

risperidone
ziprasidone
clozapine
– all black-box

50
Q

ADRs of ziprasidone:

A

black box: increased mortality in patients with dementia

51
Q

Black-box warnings for clozapine:

A

1) agranulocytosis
2) myocarditis
3) dose-related seizure risk
4) orthostasis
5) increased mortality in patients with dementia

but, not associated with EPS

52
Q

Drug interactions for clozapine:

A

BZDs:
– hypotension, respiratory depression
cigarettes:
– increased metabolism

53
Q

MoA of clozapine:

A

low D2 and high 5-HT2a receptor antagonist

54
Q

When is clozapine especially useful?

A

1) alleviation of positive symptoms (superior efficacy)
2) negative cognitive sxs (superior)
3) hostility and suicidality (superior to FGAs)

55
Q

MoA of aripiprazole:

A

partial D2 agonist

full 5HT2a antagonist

56
Q

What antipsychotics are available as long-acting injectables?

A

1) haloperidol
2) fluphenazine
3) risperidone
4) olanzapine
5) palperidone
6) aripiprazole

57
Q

When are long-acting injectables preferred?

A

poor adherence
dose-dependent ADRs
– minimize peak-trough

58
Q

Describe symptoms resolution timelines for positive and negative sxs.

A

psychomotor: 1 week
hallucination: 2 weeks
delusions: 3+ weeks
negative: 16 weeks

59
Q

Why might polypharmacy be used?

A

1) to target sxs
2) to improve cognitive ability during cross-taper
3) to counteract side effect

60
Q

What are arguments against polypharmacy?

A

no sufficient evidence of benefit

    • dose-related ADRs
    • more risk for cognitive impairment
61
Q

What drug is OFTEN augmented with another drug?

A

clozapine

    • to reduce negative sxs
    • take 10 weeks to observe benefit
62
Q

What are the phases of therapy?

A

acute psychosis
stabilization
maintenance

63
Q

What is the GoT in acute psychosis?

A

manage acute sxs

prevent threat to self

64
Q

What is the GoT in stabilization

A

reduce ADRs

maintain compliance

65
Q

What is the GoT in maintenance?

A

improve psychosocial functioning and QoL

prevent relapse

66
Q

What SGAs have the least risk of weight gain?

A

ziprasidone, aripiprazole

67
Q

How to manage the metabolic syndrome ADRs of SGAs?

A

change drug if 5% weight gain

– to avoid risk of T2DM