APS Flashcards
schizo – theory
1) dopamine theory: Amphetamine (overactive DA) produce similar sx to acute schizophrenia
* All antipsychotic drugs are D2 antagonists
2) 5HT theory: LSD (blocks 5HT) produce schizo sx
3) glutamate theory: ketamine (block NMDA receptor) produce schizo sx
5 schizo sx domains
1) +ve sx (abnormal behaviour)
2) -ve sx (substracted normal behaviour)
3) aggressive sx
4) ANX/ DEP
5) cognitive sx
DA pathways (1) DA theory
Nigrostriatal pathway (D1, D2)
- substantia nigra –> dorsal striatum
Mesolimbic pathway (D2, 3)
- ventral tegmental area (VTA) –> Limbic (emotional) brain
Mesocortical (D4)/ mesolimbic pathway
- ventral tegmental area (VTA) –> prefrontal cortex (emotional)
Tuberoinfundibular pathway (D3)
- hypothalamus –> anterior pituitary
Nigrostriatal pathway
substantia nigra –> dorsal striatum
Voluntary movement , prevent other movements
- inhibit D2: EPSE (pseudo-parkinsonism)
Mesolimbic pathway
ventral tegmental area (VTA) –> Limbic (emotional) brain
Reward and emotion
- inhbit D2: reduce +ve sx, reduce schizo sx
Mesocortical pathway
ventral tegmental area (VTA) –> prefrontal cortex
motion, cognition, attention
- Higher order thinking
- Executive functions
- inhibit D2: hypofunction, results in -ve sx
Tuberoinfundibular pathway (D3)
hypothalamus –> anterior pituitary (infundibular)
DA inhibits prolactin secretion into blood circ
- inhibit D2: hyperprolactinemia (more prolactin released)
1st vs 2nd gen
BOTH: block dopamine pathways = Control +ve sx of schizo
EPSE in 1st gen > 2nd gen
FGA eg
chlorpromazine
haloperidol
sulpiride
- D2 antagonism
SGA eg
clozapine
olanzapine
quetiapine
risperidone
amisulpride
brexipiprazole
- serotonin-dopamine antagonism (SDA: 5HT, DA) + complex mix
FGA SE
○ M1: dry mouth, constipation, blurred vision
○ H1: sedation, weight gain
○ A1: postural hypotension, dizzy
○ DA: EPSE, prolact
EPSE
- Pyramidal motor pathway is output from primary motor cortex
○ via pyramids of medullar oblongata –> spinal cord
○ Involves basal ganglia: (striatum, substantia nigra)
- (Tardive dyskinesia + Akathisia) Occur in 20-40% of pt on typical antipsychotics, IRREVERSIBLE dyskinesia
Upregulation or super sensitivity of dopamine receptors in nigrostriatal system - (parkinsonism) block D2 receptor in nigrostriatal, where DA neurons terminate
- (dystonia) DA hyperactivity in basal ganglia
EPSE description
- Acute dystonia – (posture, spasm)
* Parkinson-like sx: cogwheel rigidity and tremor at rest, abnormal muscle tone
* 1st few wks of tx
* Reversible when drug is stopped
- Caused by D2 antagonism in nigrostriatal pathway - Tardive dyskinesia – uncontrolled facial, jaw movements
* Slow (tardive) over mnths/ yrs of tx
* Repetitive (dyskinesia)
* irreversible
- stereotyped involuntary movements of face, tongue, limbs - Akathisia – restlessness
* Involuntary movements (akathisia)
* compulsion assoc with restlessness, ANX, agitation
- Correlates directly to duration on meds
SGA – atypical
produce less EPSE. more metabolic (-ine)
complex mixtures of actions:
- greater affinity for 5HT2 receptors
- greater affinity at D4 receptors
- mixed antagonism: a-adrenoceptor, H1, M1, 5HT2 receptor
diff SGA drug, diff receptor affinity – SE, efficacy
- Amisulpride (D2, D3, reported 5HT7)
- Fewer SE due to D2,3 receptor selectivity
○ D2,3 antagonist: prolactin release incr (breast pain, swell, lact)
○ Absence of a1, H1, M1 antagonist SE
- Fewer SE due to D2,3 receptor selectivity
- Clozapine
- M1: dry mouth, constipation, blurred vision
- H1: sedation, weight gain
- A1: postural hypotension, dizziness
- D1,2,3,4
clozapine ADR
Clozapine-induced agranulocytosis
○ <1% of pt but fatal
○ Lack of granulocyte type WBC (monitor regular blood counts)
–> olanzapine (similar effect w/o this ADR)
drug-induced DM
clozapine, olanzapine, risperidone
(amisulpride exception)
MOA: unknown - may involve 5HT antagonism
* in hypothalamus
* in pancreatic beta cells
drug-induced weight gain
SGA: clozapine, olanzapine, risperidone
MOA: sedation (H1 antagonism) –> incr sedentary behaviour
maybe: A1 , 5HT2 antagonism on hypothalamus & feeding behaviour
WHY SGA < FGA EPSE
- more 5HT2A receptor antagonism > D2 antagonism = less EPS, less -ve sx too
- high D3 to D2 antagonism ratio (more action on nucleus accumbens > striatum = more DA receptor for EPSE)
- high D4 to D2 antagonism ration (action in prefrontal cortex > striatum)
/targets emotion, +ve sx control - high D2 to D1 antagonism ratio (less complete blockade of DA function as D2 antagonism at presynapse will iNCR DA RELEASE)
/ presynaptic D2 receptor as a feedback regulation
additional benefits of SGA
- more effective against -ve sx (clozapine, olanzapine, risperidone)
- cognitive dysfunction sx control (clozapine, risperidone)
- mood stabilisation (clozapine, olanzapine, risperidone)
FGA: more on +ve sx control (not much for -ve sx, cognition and mood stability)
PK of APS and onset (tmax)
BAO
- SGA
* (long tmax) olanzapine 6hrs, aripiprazole 3-5hrs, brex 4hrs - most FGA, SGA: tmax= 1-3hrs
PK of APS and dosing freq (t1/2)
(divided dosing due to risk of hypoTEN, seizure)
- FGA
* (divide dose): chlorpromazine, sulpiride - SGA
* (divided dose): amisulpride, clozapine, quet, ziprasidone
most FGA, SGA
* long t1/2: OD dosing
eg haloperidol 12-36hrs
PO APS potency
HOR
low potency: sulpiride, chlorpromazine, Amisulpride, clozapine, quetiapine
high potency: risperidone (2-6mg), haloperidol, olanzapine (5-15mg)
dosing freq of LAI
- haloperidol decanoate: 2-4w
- risperidone: 2wk, suppl PO for first 3 wks reach stabilisation
- paliperidone: 3mnths
relative SE
- FGA
- EPSE – MOST
- Prolactin – ALL
- Weight gain – chlorpromazine, perphenazine
- Pro convulsation – chlorpromazine, cloxapine
- Cardiac – thioridazine
- Anticholinergic – chlorpromazine
- Hypotension: chlorpromazine
- SGA
- Weight gain : clozapine, olanzapine
- Anticholinergic : clozapine
- Cardiac: clozapine, ziprasidone
- Sedation: clozapine
EPSE
- acute dystonia (abnormal, prolonged contraction of any muscle grp)
○ anticholinergics - parkinsonism (tremor, muscular rigidity, flattended effect, loss of movement, bradykinesia)
○ anticholinergics - akathisia (restlessness, fidget)
○ BZP, propranolol - tardive dyskinesia (involuntary orofacial muscle)
○ valbenazine
EPSE – dystonia (muscle spasm)
- IM/IV > PO hrs
- Risk: high potency, neuroleptic naïve pt, young M
- Manage: IM anticholinergics (benztropine, diphenhydramine)
EPSE - pseudo parkinsonism manage
(tremor, rigid, bradykinesia, salivation)
○ Risk: elder F, previous neurological damage (head injury, stroke)
○ Manage: decr antipsychotic dose, switch to sga
○ Anticholinergics PRN (benztropine)
EPSE - tardive dyskinesia (orofacial movement, chew/ tongue protusion, repetitive. Late onset 3-6mnths)
- Risk: FGA > SGA, those develop acute EPSE when started on FGA. Worsens with anticholinergic. May be irreversible
- Manage: discontinue anticholinergics
○ Decr dose, switch to SGA (clozapine)
○ Reversible inhibitor of vesicular MAO transporter 2 (VMAT2) = valbenazine 40-80mg/ day
○ BZP: Clonazepam PRN
hyperprolactinaemia
- Galactorrhea, amenorrhea, decr libido, gynecomastia (M)
- Risk: FGA (Pali =/> RISP > OTHERS)
- Manage: decr FGA dose, dopamine agonist (amantadine, bromocriptine)
* Switch to aripiprazole
metabolic SE
- Weight gain (>7% from baseline), DM incr lipids
- Risk: OLAN, CLOZ > CPZ, QUET, RISP >
- Manage: lifestyle, tx DM (metformin) & hyperlipidemia
- Switch to lower risk agents (Ari, Lura, Zip, Halo)
manage CVS - ortho hypoTENsion
- orthostatic hypotension
* CPZ, CLOZ > RISP, PALI, QUET
* get up slow; switch to olan, zip, ari, sulpiride
manage CVS -QTc
- high doses, IV haloperidol, low K+, IHD, Female
- avoid: Thio > chlorpromazine > Halo > quet > risp> olan
- lower risk agents: Aripiprazole
CVS - VTE/ PE
- avoid: low potency FGA: sulpiride, chlorpromazine
- prevent, monitor and tx DVT
CNS - sedation
Risk: CPZ > CLOZ > QUET > OLAN
Manage: switch to lower risk agents. (RISP, PALI, ZIP, ARI)
CNS seizure
- Risk: CLOZ > CPZ> OTHERS SGA
- High doses, rapid titration, hx of epilepsy
- Manage: switch to high potency agents (HALO, RISP)
neuroleptic malignant syndrome is __
caused by ___
- DA blockade, cause hypothalamic dysfunction. muscle contraction & temp dysregulation
- Muscle rigidity, fever, altered consciousness, high CK, autonomic dysfunct (PR, BP, diaphoresis)
- Risk: high potency anticholinergics
- Rare, potentially lethal
- Onset: hrs - 3days (within 30d)
- Other possible causes
1. Succinylcholine/ suxamethonium (muscle relaxant)
2. Antipsychotics D2 blocker
3. Sudden discontinuation Levodopa (LT dopamine agonist)
manage NMS
- Manage: IV dantrolene 50mg TDS, PO dopamine agonists (amantadine, bromocriptine)
- Supportive measures
- Switch to SGA
psychogenic polydipsia
self-induced water intoxication
- avoid: anticholinergics
- manage: fluid restriction, discontinue drug with anticholinergics effect (anta M1, Ach)
temp dysregulation
- avoid anticholinergics
- manage: hydration, app clothes + shade
hepatic SE
- Incr LFT, cholestatic jaundice (CPZ)
- Risk: CPZ (FGA), OLAN, QUET > OTHER SGA
- Manage: jaundice develops = discontinue and switch to safer agents
sulpiride, ami
opthalmologic
- Cornea/ lens changes, pigmentary retinopathy
- Risk: phenothiazines (CPZ, THIO), Quet
- Manage: pt on QUET (eye exam q6mnths)
dermatologic
- Maculopapular rash, photosensitive, pigmentation
- Risk: CPZ
- Manage: protective clothing, sunscreen
* Consider switch to other antipsychotics
hematologic
- Decr WBC, agranulocytosis (absolute neut count ANC)
- Risk: clozapine
- Manage: discontinue antipsychotics if severe
* WBC < 3x 109/L or ANC < 1.5x 109/L
monitor SE
(every visit)
- vitals
* BP, PR, temp
- SE:
* EPSE exam, plasma prolactin (libido, gynecomastia)
- mental state:
* suicidality, MSE
(12wks, annual)
- metabolic:
* BMI, waist circumference, Fasting blood sugar, lipid panel
- ECG (Qtc prolongation)
(wkly 18wks, mnthly)
- WBC, ANC (clozapine)
preg
avoid OLAN, CLOZ: Gestational DM
breastfeed
OLAN, QUET suitable
CLOZ continue + not breastfeed
renal impairment
oral aripiprazole
avoid: sulpiride, amisulpride
hep impairment
sulpiride, amisulpride preferred
elderly
- Avoid drug with high propensity for a1 blockade = hypotension
- Avoid drugs with Ach SE = Constipation, urinary retention, delirium
○ Start low, go slow. Simplify regime, avoid DDI, avoid long t1/2 drugs (split) - Caution: FGA, SGA - incr mortality, CVA in dementia pts
PD int
(6)
- CNS depressants: alcohol, codeine, hydroxyzine, psychotropics
- additive effects: anti M1, H1, A1, DA (hypotension) BP meds
* Parkinson (nullify effect): dopamine agonist, levodopa - 5HT augmenting agents (antagonise 5HT2A receptor block, decr DA release, worsen EPSE)
- EPSE, NMS: metoclopramide, psychostimulants
- seizure: lower the seizure threshold, incr seizure risk
- incr toxicity: Li, TCAs
- agranulocytosis (CBP + cloz)
PK int
- P1: oxidation, reduction, hydrolysis
○ CYPP450, 1A2, 3A4, 2D6 - P2
○ Glucuronidation, coupling
CYP1A2
- inducers: rifampicin, PB, PT, smoke
- inhibitors: fluvoxamine, ciprofloxacin, quinolones, macrolides, isoniazid, ketoconazole
(halo, cloz, olan, zip)
CYP2D6
- inducers: rifampicin, PB, PT, CBP
- inhibitors: fluoxetine, paroxetine - ssri, duloxetine - snri
(halo, risp, ari, olan)
CYP3A4
- inducers: barbiturates, CBP, PT, rifampicin, st john’s
- inhibitors: azoles, TCA, fluvoxamine, isoniazid, macrolides, grapefruit
quet, zip, Ari, Risp, brexipip