Typical and atypical Psychotics Flashcards
High potency typical antipsychotics
Haloperidol strongest potency
Fluphenazine
Trifluroperazine
“Hal Tries to Fly HIGH”
Block Dopamine D2 receptors and need very little doses to take affect
tend to have more EPS symptoms as ADRs
also tend to have higher chances of developing neuroleptic malignant syndrome in genetically predisposed patients
lower off target ADR profile
Indications for antipsychotics
Schizophrenia
- typical only treats primary symptoms, atypical treats both primary and secondary. therefore atypical antipsychotics are preferred and first-line.
- *clozapine specifically for treatment-resistant schizophrenia
Psychosis
- drug-induced
- Parkinson-induced (best used is quetiapine)
- depression-induced
- dementia-induced
(Must be careful in dementia thou since elderly with dementia-related psychosis treated with atypical antipsychotics have increased stroke risk)
Bipolar disorder
Delirium
Tourette syndrome
Huntington’s disease
OCD
Manic episodes
- atypicals are is first line in non pregnant patients
- haloperidol is first line in 1st trimester pregnant patients
- quetiapine is first line in all trimesters
Anxiety and Irritability in severe autism for children 6-17 yrs
- risperidone and aripiprazole are the best
Pruritis
- blocks histamine receptors
- NOT first line
Intractable hiccups
- chlorpromazine only (after trying everything else in the book)
Preoperative sedatives
Possess Antiemetic effects: (lowers vomiting/nausea) in patients with syndromes that are assocaited with increased vomiting/nausea
Targets for typical antipsychotics
D2 receptors that are most commonly found in the mesolimbic and mesocortical pathways
- also blocks the dopamine receptors in the nigrostriatal pathway and tuberoinfundibular which causes the ADRs
because of this, positive symptoms go away, but negative symptoms often stay or get worse
Mesolimbic and mesocortical pathway
Controls motivation and desire and the emotions of the patient
- common site for antipsychotic treatments
- mesolimbic dysregulation due to hyperactivity of dopamine receptors causes the positive symptoms seen in schizophrenia and psychosis.
- mesocortical dysregulation due to hypoactivity of dopamine receptors causes the negative symptoms seen in schizophrenia and psychosis.
this is why adding levodopa/amphetamines/bromocriptine/apomorphine (dopamine agonists) to a non-psychotic patient can induce psychosis as a symptom
Drugs that can induce psychosis de novo or increase schizophrenia psychosis
Levodopa
Amphetamines
Bromocriptine
Apomorphine
Nigrostriatal pathway
Pathway that is used by motor neurons that bypass the medullary pyramids
Controls involuntary movements and coordination
- blocking of this pathway via antipsychotics can induce EPS and motor disturbance ADRs.
- The site of ADRs associated with EPS symptoms*
Tuberoinfundibular pathway
Pathway that keeps prolactin in check by releasing dopamine
- bloackage of D2 receptors causes hyperprolactinemia
more common in high potency typical and atypical antipsychotics (haloperidol, risperidone, etc.)
Medullary periventricular pathway
Pathway that regulates eating behavior
blocking this pathway causes over indulgence in eating and lowered metabolism, hence why obesity, hyperglycemia and dyslipidemia are common ADRs among antipsychotics
Low potency typical antipsychotics
Thioridazine
Chlorpromazine
Thiothixene
“Cheating Thieves are LOW”
Block dopamine (D2) receptors and require high doses to take effects
tend to have lower on target ADR profiles (EPS “ADAPT” and hyperprolactin), but higher off target profiles (sedation/weight gain/ANTI-SLUD/orthostatic hypotension/etc).
EPS side effects of antipsychotics
“ADAPT”
Typical antipsychotics cause these ADRs more often than atypical
1) hours -> days after beginning treatment
- Acute Dystonia (muscles spasms) of the face/tongue/neck/back, and/or oculogyric crisis
* treatment = benzotropine or diphenhydramine*
* *also can give amantadine, but not 1st line since it can override the antipsychotic**
2) days -> months after beginning treatment
- Akathisia (restlessness)
* treatment = BBs, clonazepam or benzotropine*
- Parkinsonism (bradykinesia and mask facies)
- treatment = Benzotropine or amantadine*
3) Months -> years after beginning treatment
- Tardive dyskinesia (chorea often of the face, but can be of the body also)
- must discontinue use if #3 is seen, since it is irreversible*
- # 1-2 are treatable and reversible*
** amantadine (dopamine agonist) also works in replacement of benztropine, however it less used since it counters the antipsychotic drug effect directly where as benztropine does not (anticholinergic drug)
Neuroleptic malignant Syndrome (NMS)
A life-threatening EPS that can occur in patients who have a pregenetic disposition for it and take antipsychotics
- more common in high potency typical agents
“Looks like severe Parkinsonism with autonomic instability”
Basic Symptoms: (starts days-> weeks after tx)
- confusion
- seizures
- agitation
- hyporeflexia*
- normal pupils*
- hyperthermia throughout body
- = ways to tell this apart from serotonin syndrome *
Severe symptoms: (starts days-> weekly after tx)
“Malignant FEVER”
- Myoglobinuria
- Fever
- Encephalopathy
- Vitals are unstable
- increased Enzymes
- muscle Ridgitiy
- death = coma
Treatment:
- take off medication and give dantrolene or bromocriptine
- the earlier caught the better
Note: that even with proper treatment, NMS can still persist for more than a week after proper treatment. If this is the case = high mortality so need to watch patient closely.
Non-dopamine related side effects of antipsychotics
Orthostatic hypotension and lightheadedness :
- blockage of a1 receptors
Anti cholinergic (ANTI-SLUD) - blockage of Muscarinic receptors
Sedation and weight gain
- blockage of Histamine H1 receptors
- low potency antipsychotics have a high chance of causing this*
Prolonged QT intervals
Metabolic disorders
- hyperglycemia/dyslipidemia
What are the specific ADRs associated with chlorpromazine and thioridazine?
Corneal and retinal calcium deposits respectively
Atypical psychotics
Aripiprazole
- highest D2 potency of atypicals
- is a dopamine and 5-HT(1a) partial-agonist*
- antagonist at all receptors it hits
Asenapine
Clozapine
- lowest D2 potency of atypicals
- highest D4 receptor potency
Olanzapine
- highest serotonin inverse agonism
- binds strongest to 5-HTA2 receptors
Quetiapine
- highest histamine potency, lowest serotonin inverse agonism
- highest odds of sedation and weight gain among atypicals
- least likely to cause EPS of all antipsychotics
- best used in patients who have Parkinson-induced psychosis
Iloperidone
Paliperidone
Risperidone
-high potency for D2 as well
Lurasidone
Ziprasidone
- MOA is not fully understood but most work as inverse agonists for serotonin (5-HT2A) and antagonists for dopamine (D2 and D4) receptors*
- apripiprazole = partial dopamine agonist
Why does atypical antipsychotics possibly work on negative symptoms of schizophrenia?
Blocks the inhibitory serotonin neurons located in the mesocortical Pathway
- these neurons keep dopamine levels low when active, but when blocked raise levels of dopamine in the pathway. This “cures” the negative symptoms
note: it doesn’t actually cure, rather than just not make them get worse or slightly improve them
Clozapine only specific ADRs
Agranulocytosis, leukopenia, granulocytopenia, and dose-related seizures
- rare but fatal*
- must monitor WBCs and bone marrow while on it.
- ** discontinue if the WBC count is below 3,000cells/mm or granulocyte is below 1500cells/mm**
- patients are also more susceptible to atypical infections
Myocarditis and cardiomyopathy
- rare but fatal if not caught
- must monitor patients for chest pain, dyspnea, fever, tachypnea
Severe small bowel constipation
- can cause obstruction and subsequent rupture of intestines fatal
- MUST use in conjunction with stool softeners if constipation develops.
because of these it is usually last-line only and used only for treatment resistant psychosis/schizophrenia
** also is known to cause drooling/hypersalivation, even though it has anti-cholinergic side effects. Treatment of this ADR = glycopyrrolate**
Tuberoinfundibular side effects of antipsychotics
Blockage of dopamine receptors in this pathway causes hyperprolactinemia since there is no regulation of this hormone present (dopamine is responsible for this)
Symptoms:
- amenorrhea
- galactorrhea
- gynecomastia
risperidone is the most commonly associated antipsychotic with these symptoms (but all can cause it)
Why do typical antipsychotics generally cause more EPS symptoms than atypical antipsychotics
Because typical antipsychotics bind tightly to D2 receptors (non competitive binding), and atypical antipsychotics bind loosely (competitive binding) so atypical can be overridden in high doses of dopamine.
potency of typical = haloperidol > fluphenazine > chlorpromazine > thioridazine