Antipsychotics Flashcards
how do antipsychotics work?
Dopamine 2 receptor antagonism
what pathways do they work on?
mesolimbic
nigrostriatal
mesocortical
tuberoinfundibular
what do antipsychotics do to the mesolimbic and nigrostriatal pathways?
Decrease the mesolimbic pathway therefore decreasing POSITIVE Sx eg. 3rd person auditory hallucinations
Decrease nigrostriatal pathway (extra pyramidal Side effects eg. Parkinsons Sx)
what do antipsychotics do to the mesocortical and tuberinfundibular pathway?
Mesocortial - Negative Sx
Tuberinfundibular - Prolactin
what condition can interference with the tuberinfundibular pathway cause and why? Sx?
DA blockade can cause HYPERPROLACTINEMIA
(prolactin = inhibited by DA therefore low DA = HIGH prolactin)
Sx= Lactation, low libido, infertility
how are antipsychotics reduced and why?
gradual reduction when stopping (over 3+ months) to prevent relapse
are antipsychotics addictive?
no
what tests are done at a review and how often are reviews done?
12 monthly reviews
FBC, U+E, LFT, HbA1C, BMI, Prolactin
what are the 2 types of antipsychotics?
Typical (1st gen)
Atypical (2nd gen)
name 2 typical antipsychotics?
haloperidol
chlorpromazine
what are the typical antipsychotics associated with?
extrapyramidal SE (EPSEs)
What 4 SE do typical antipsychotics give?
acute dystonic reaction
akathisia
Parkinsonism
tardive dyskinesia
what is acute dystonic reaction?
Tx?
involuntary muscle contractions
Rapid onset oligogyric crisis (involve eyeball movements, eyes are up)
or TORTICOLLIS (stiff neck, hard to turn)
Tx = IM/IV procyclidine (anti Ach)
and switch to 2nd gen or benzotropine
what is akathisia?
Tx?
rapid onset LL motor restlessness
Tx = PO Propanolol (BB)
Parkinsonism
Tx?
LDOPA
what is tardive dyskinesia?
Tx?
Years after, irregular dyscoordinated, purposeless movement
Tx = PO tetrabenazine (VMAT2-i)
Switch to 2nd gen
what are 2 things antipsychotics cause/exacerbate?
exacerbate parkinsons
cause VTE + stroke in elderly
Name a few atypical antipsychotics?
Risperidone
Olanzipine
quetiapine
aripiprazole
clozapine
what are atypical antipsychotics associated with?
metabolic syndromes (eg. T2DM + cushings)
when do we prescribe clozapine?
why?
last line after 2 different antipsychotics trialled
Only antipsychotic proven to treat NEGATIVE Sx
(mesocortical pathway involved in -ve Sx pathway)
why is it such a good drug compared to other antipsychotics?
antipsychotics usually exert their force on the mesolimbic pathway only but clozapine acts on both mesolimbic and mesocortical
what monitoring takes place for clozapine and how often?
18 weeks - WEEKLY
16 weeks - 2 WEEKS
then monthly
monitor FBC, U+E, LFT, prolactin, BMI, SE
what are some side effects of clozapine?
AGRANULOCYTOSIS (sore throat with clozapine)
hyper salivation
weight gain
constipation (to become a bowel obstruction)
what are 2 reasons you would need to reiterate the antipsychotic?
Dose missed >48hrs
if smoking status changes
