Antipsychotics Flashcards
What is the mechanism of action of antipsychotics?
- reduce levels of dopamine activity at D2
- targeting mesocortical and mesolimbic
What are some indications for antipsychotics?
schizophrenia 3rd line when 2 others have failed
positive psychotic symptoms in depression, dementia, mania etc
violent, impulsive, psychomotor agitation
Actions on what pathway causes the unwanted effects of antipsychotics?
nigrostriatal (movement) and tuberoinfundibulnar (HPA axis)
As a whole what side effects do antipsychotics cause?
sedation
extra-pyramidal
weight gain
increase in prolactin
potential: acute dystonia, oculogyric crisis
What are the two types of antipsychotics?
typical - older, causes more extra-pyramidal side effects! histaminic and muscarinic receptors
atypical - serotonergic activity
What are some common typical antipsychotics?
haloperidol
flupenthixol
zuclopenthixol (accuphase)
chlorpromazine
sulpride
What are some common atypicals?
clozapine
olanzapine
risperidone
quetiapine
aripiprazole - partial D2 agonist, fewer SE
What are extra-pyramidal side effects?
bradykinesia
muscle stiffness
tremor
tardive dyskinesia - oropharynx
akathisia - urge to move
*typicals + dizzy and sexual dysfunction
What side effects are atypicals more likely to cause?
weight gain
dyslipidaemia
diabetes
What are the baseline investigations for antipsychotics starting?
FBC - BM suppression
lipids - increase in cholesterol
LFT - fatty liver
HbA1c - impaired glucose tolerance
weight -gain
ECG - QTC prolong
BP - metabolic syndrome
pulse - ^^
How often are investigations done for monitoring of antipsychotics?
baseline
weekly weights
3 monthly all
yearly all
What is neuroleptic malignant syndrome?
life threatening reaction to antipsychotics, or with dopaminergic drugs for Parkinson’s when suddenly stopped
dopamine blockade –> glutamate release –> damage to muscles and nerves
What is seen in NMS?
pyrexia
muscle rigidity
sweating
confusion
fluctuating consciousness
autonomic instability - high HR etc
What do the investigations show in NMS?
raised CK
leucocytosis?
deranged LFT
What causes death in NMS?
rhabdomyolysis induced renal failure
seizures
VTE and PE due to immobilisation
shock
aspiration due to swallowing issues
What treats NMS?
A&E
stop antipsychotic
benzo for acute disturbances
monitor vitals
IV fluids to prevent renal failure
dantrolene (muscle relax)
Why would you consider anticholinergics to treat EPSEs?
if too much ACh in relation to dopamine you cannot increase dopamine activity –> reduce ACh by antagonising receptors
eg: Procyclidine (not for tar dive dyskinesia)
What is an acute dystonia?
sustained, painful muscle spasm producing twisted and abnormal postures
–> stop antipsychotic, IM or IV anticholinergic like procyclidine
What are some Clozapine specific side effects?
hypersalivation
agranulocytosis ( severe leukopenia like neutrophils)
GI hypo-mobility - bowel obstruction?
urinary incontinence
What are some steps taken to avoid the clozapine side effects?
close FBC monitoring for agran - weekly for first 18 weeks, then fortnightly for a year then monthly
titrate up slowly over 2 weeks and monitor vital signs for autonomic dysreg.
how would you treat agranulocytosis?
stop clozapine
stop any marrow suppressing drugs
avoid other antipsychotics, apiprazole if needed
haematology input
abx prophylaxis
lithium to increase WCC?
G-CSF
