Pharmacology of Psychosis Flashcards
Dopamine Pathways in Schizophrenia
Mesolimbic - increased activity
Mesocortical - decreased activity
Nigrostriatal - no change
Tuberoinfindibular - no change
Antipsychotics & Dopamine
Antipsychotics act on dopamine pathways
First Generation / Typical Antipsychotics
Work by blocking the D2 receptor. This has the following schizophrenic effects on the different pathways.
Mesolimbic –> decrease positive symptoms
Mesocortical –> worse cognitive symptoms
Nigrostriatal –> EPS, tardive dyskinesia, akathisia
Tuberoinfandibular –> hyperprolactinemia
Second Generation / Atypical Antipsychotics
Work by blocking the D2 receptor and the 5HT2A receptor which is a serotonin subtype receptor. Serotonin inhibits dopamine release from dopaminergic axon terminals and blocking this receptor allows dopamine to be released from these axon terminals.
Mesolimbic –> reduced positive symptoms
Mesocortical –> improved negative cognitive symptoms
Nigrostriatal –> little or no EPS, tardive dyskinesia, akathesia
Tuberoinfandibular –> little/no hyperprolactinemia
Examples of 1st Gen Anti-psychotics
Haloperidol (Haldol)
Chlorpromazine
Side effects include EPS, hyperprolactinemia, tardive dyskinesia, as well as anticholinergic and antihistamine effects
Examples of 2nd Gen Anti-psychotics
Olanzapine
Risperidone
Clozapine
Quetiapine (seroquel)
Ziprasidone
Side effects include weight gain, impaired glucose tolerance, and sedation. With clozapine it also may cause agranulocytosis.
Olanzapine
A 2nd G anti-psychotic
Pros - patients can tolerate high doses
Cons - weight gain and metabolic syndrome
Risperidone
A 2nd G anti-psychotic
Pros - less weight gain and depo available
Cons - most EPS / prolactin of 2nd Gen
Quetiapine (Seroquel)
2nd G antipsychotic
Pros - no EPS
Cons - weight gain & sedation
Ziprasidone
2nd G antipsychotic
Pros - no weight gain
Cons - cardiac arrythmias (QT prolongation) & agitation when starting
Clozapine
2nd Gen antipsychotic
The most potent of all anti-psychotics but has the worst side effect profile.
Agranulocytosis of 0.8% which requires strict blood monitoring.
Use only after failing 2 antipsychotics of which 1 must have been a 2nd Gen.
Third Generation Anti-psychotics
Partial D2 agonist and 5HT2A blocker.
Aripiprazole (Abilifiy)
Many of the similar side effects to 2G antipsychotics but causes lower rates of metabolic syndrome and weight gain.
Aripiprazole (Abilify)
3G Antipsychotic
Many similar side effects to 2G but lower rates of weight gain and metabolic syndrome.
