Rx: Antipsychotics Flashcards
psychosis MOA
inc dopamine activity, as w/amphetamines, metylphenidate, or cocaine
antipsychotics blocking D2 receptors have what effect?
relieve positive sx
antipsychotics blocking 5HT2 receptors have what effect?
relieve negative sx
antipsychotics blocking a1 receptors have what effect?
produce autonomic SEs, like orthostatic hypOTN and tachycardia
antipsychotics blocking H1 receptors have what effect?
produce sedation
antipsychotics blocking muscarinic receptors have what effect?
produce confusion and memory impairment, provides protection against EPS
which antipsychotics show a lower affinity for D2 receptors and higher affinity for 5HT2 receptors?
atypical (2˚) antipsychotics
-lower affinity for D2 receptors reduces the risk of EPS
potent antipsychotics
inc risk of EPS
weak antipsychotics
additional sedative, hypOTN and autonomic SEs
typical antipsychotics
dopamine D2 blockers, produce EPS, elevate PRL levels, equally effective but differ in potency/SEs, largely effective for positive sxs (e.g. delusions, hallucinations, disorganization of thought and behavior)
atypical antipsychotics
D2 and 5HT2 antagonism, but addition of 5HT2 blockade may reduce EPS and improve efficacy for negative sx (e.g w/drawal, flat affect, paucity of thought, avolition)
chlropromazine: structure
aliphatic side chain, low potency= lower incidence of EPS
thiothixene: structure
piperidine ring, low potency= lower incidence of EPS
fluphenazine, perphenazine: structure
piperazine, potent= higher incidence of EPS + weak anticholinergic
haloperidol: structure
high potency
atypicals: clozapine, olanzapine, quetiapine
low potency, have addtnl anti-serotonin effects –> tx neg sx
which atypical acts like a typical antipsychotic?
risperidone, greater risk of EPS at high doses
*only approved agent for use in children and teens
what its the active metabolite of risperidone?
paliperidone
which risperidone has limited EPS?
ziprasidone
what is unique about aripiprazole?
PARTIAL AGONIST for dopamine receptors rather than an antagonist, 5HT2A antagonist, 5ht1A partial agonist
-lower incidence of SEs
neuroleptic syndrome
suppression of spontaneous movements and complex beh, reduced initiative and interest in environ, dec manifestations of emotion or affect, psychotic sx disappear over time
which class of drugs can cause neuroleptic syndrome?
antipsychotics
limbic system
thought to be site of antipsychotic effects, dopamine system adapts to long-term therapy, Anticholinergics do not block therapeutic effect
basal ganglia
dec dopamine=dec EPS, like limbic system dopamine will adapt (initially inc dopamine metabolism, synthesis, and firing rate); anticholinergics block anti-psychotic induced inc in DA turnover in basal ganglia, and thus block many sx of EPS
*antipsychotic effect not thought to occur here
