Antipsychotics Flashcards
typical antipsychotics are best for treating symptoms associated with which brain pathway? what are the symptoms?
mesolimbic dopamine pathway
positive symptoms - delusions, agitation, hallucinations and disorganized thinking
blocks D2 receptors
what are the affects of blocking D2 receptors in the mesolimbic dopamine path?
worsens negative symptoms
what is the effect of blocking D2 receptors in the nigrostriatal pathway?
extrapyramidal symtoms
parkinsonism symptoms
blocking D2 receptors in tuberoinfundibular pathway has what type of affect?
prolactin release
what are the indications for treating with typical antipsychotics?
schizophrenia
drug-induced psychosis
manic phase of bipolar I disorder
nausea, vomiting, gastroparesis - metaclopramide
tourettes - haloperidol and pimozide
sedation, urinary retention, extrapyramidal symptoms, akathisia (leg twitching) menstrual irregularities, tardive dyskinesia and neuroleptic malignant syndrome are all symtoms of toxicity with what type of drugs?
typical antipsychotics
what is tardive dyskinesia?
decreased DA release leads to upregulation of receptors
this effect can happen months to years later
rabbit syndrome - tongue protrusion, lip-smacking and abnormal movements
for this reason it is best to start with the lowest dose and asses
what is neuroleptic malignant syndrome
muscle rigidity, loss of consciousness, tachycardia, high fever, diaphoresis and elevated creatine kinase
how do you treat NMS?
discontinue drug and provide supportive care
give dantrolene and brobromocriptine
dantrolene
treatment for NMS and malignant hyperthermia
muscle relaxant
binds ryanodine receptor and prevents release of calcium from the sarcoplasm
chlorpromazine
typical antipsychotic
low potency
high blockade of muscarinic, histamine and alpha1
corneal deposits
thioridazine
typical antipyschotic
low potency, most muscarinic, histamine and alpha1 blockade
high QT interval
which typical antipsychotics have high potency?
fluphenazine and haloperidol
most D2 blockade
thioridazine
typical antipsychotic
causes pigment retinopathy
how do you treat typical antipsychotic toxicity?
treat dystonia and parkinsonism with anticholinergics - benztropine, diphenhydramine
amantadine
treat akathisia with propranolol
benzotropine - what is ti? how does it work? what is it used for?
muscarinic blocker
prolongs dopamine levels and helps with tremor associated with D2 antagonists
other drug - trihezyphenidyl
muscarinic block toxicity effects
dry eyes, dry mouth, dry skin, constipation
hyperthermia, tachycardia
confusion, delirium, and hallucination
explain the serotonin hypothesis about schizophrenia
It is thought there is a connection between psychosis and serotonin because LSD mimics psychotic symptoms.
serotonin inhibits the release of dopamine in the nigrostriatal pathway which decrease extrapyramidal symptoms
5-HT2A block in the tuberoinfundibular pathway decrease release of prolactin
the block of 5-HT2A in the mesocortical pathway increases dopamine which improves negative symptoms
blocking 5-HT2A does not increase dopamine levels in the mesolimbic pathway
how do atypical antipsychotic work?
blocks 5-HT2 and to a lesser extent dopamine receptors
the increase in DA release relieves negative symptoms or psychosis with fewer EPS and hyperprolactinemia
they all prolong QT interval
aripiprazole
atypical antipsychotic
partial D2 and 5-HT1a agonist nad 5-HT2a antagonist
used in bipolar disorder and for irritability in autism
dec DA in mesolimbic, inc DA in mesocortical
clozapine
atypical antipsychotic
binds D1 and alpha1, then 5-HT2A
causes weight gain - 5-HT2c block
can cause agranulocytosis
olanzapine
atypical antipsychotic
less ANS effects but blocks D3 and D4
causes weight gain and sedation
approved for combination with fluoxetine to treat mania
quentiapine
D2 blocker but binds for a short time
miminal muscarinic block, block H1 and alpha1 - heavily sedation
risperidone
hypotension from alpha1 blockade
increased prolactin, hyperlipidemia and hyperglycemia
paliperidone
active metabolite of risperidone
ziprasidone
blocks 5-HT and NE reuptake
causes skin reaction and eosinophilia
