Antipsychotics Flashcards
What is the major neurotransmitter that is associated with a
Schizophrenia?
Dopamine - too much gives positive symptoms and too little gives negative
Schizophrenia is involved with malfunctioning in two pathways, the mesolimbic and mesocortical. Which is involved with positive symptoms and which is involved with negative?
Over activity of mesolimbic causes positive
Under activity of mesocortical causes negative
Name two drugs that can produce a psychosis that closely mimics schizophrenia
Amphetamine and cocaine
Antipsychotic drugs work by blocking what receptor?
D2
Blocking of dopamine in the nigrostriatal pathway leads to what side effets of antipsychotics?
Parkinsonism - extra pyramidal reactions
It’s a motor pathway linking substantia nigra to the basal ganglia
Explain how blocking D2 receptors can worsen negative symptoms of schizophrenia
Neurons with D2 receptors are inhibitory to GABAergic neurons (they inhibit the inhibitor so net excitatory function). Block D2 and you get increased activity of GABAergic neurons (increased inhibitory effects) -> negative symptoms
Blocking dopamine, like in treatment for schizophrenia, can have what endocrine adverse effect?
Galactorrhea because dopamine usually inhibits prolactin
Name the four classical antipsychotic drugs
Chlorpromazine
Fluophenazine
Haloperidol
Thioridazine
The classical antipsychotics are subclassified based on potency with the higher potency drugs being MORE liekly to cause extra pyramidal effects. Name the two more potent ones
Fluphenazine
Haloperidol
The classical antipsychotics are subclassified based on potency with the higher potency drugs being MORE liekly to cause extra pyramidal effects. Name the two with lower potency
Chlorpromazine
Thioridazine
ie LESS likely to cause extra pyramidal reactions
Which subtype of antipsychotic is more effective at treating negative symptoms? Classic or atypical?
Atypical
What makes the atypical antipsychotics atypical?
They have higher affinities for receptors other than D2
Which subtype of antipsychotic is more liekly to cause tardive dyskinesia? Classical or atypical?
Classical
Which two atypical antipsychotics are LEAST likely to cause extra pyramidal reactions?
Clozapine and quetiapine
Which atypical antipsychotic is a partial agonist at D2?
Aripiprazole
What is the typical onset of action for antipsychotic drugs?
Less than 24 hours
Antipsychotics generally have an additional systemic effect outside of treatment for schizophrenia. What is it? Two exceptions
Antiemetics
Aripiprazole and thioridazine
If a patient is taking antipsychotics, what drug interactions do you have to worry about?
None they don’t interfere with the metabolism of other drugs
What drug should you NEVER give a patient suffering extra pyramidal effects from antipsychotics?
Levodopa (dopamine)
What is the treatment for extrapyramidal effects caused by antipsychotics?
Benztropine
Trihexyphenidyl
Diphenhydramine
Amantadine
Akathisia is a common adverse effect of antipsychotics. What is it and what drugs do you use to treat it?
Feeling of inner restlessness
Treat with propranolol (beta blocker) or clonazepam (benzo)
Patient taking haloperidol presents with rigidity, tremor, hyperthermia, altered mental status, inc WBC count, increased CK. diagnosis? How do you treat?
Neuroleptic malignant syndrome - AE of antipsychotics (rare but life-threatening)
Give dantrolene or bromocriotine (dopamine agonist)
What is the most significant and potentially irreversible adverse effect of antipsychotics? What is it? How do you treat it? (4)
Tardive Dyskinesia
Stop or reduce dose of antipsychotic
Eliminate all drugs with central anticholinergic effects (esp antiparkinsonian drugs and TCAs)
Give diazepam
Clozapine for patients with TD that require antipsychotics
Patient taking antipsychotics presents with seizures. Which two drugs are most likely to be causing these symptoms?
Clozapine (atypical) and chlorpromazine (classical)
If you prescribe a patient clozapine, what follow up testing is mandatory? Why?
Regular CBC
Causes agranulocytosis in 1-2% of patients
Female Patient taking antipsychotis presents with complaints of amenorrhea but infertility. Explain
Blockade of dopamine from her antipsychotics removed the inhibition dopamine had on prolactin. Increased prolactin levels are probably causing her symptoms.
Atypicals are LESS likely to elevate prolactin
You prescribe an atypical antipsychotic. What effects might you warn the patient about concerning her weight? How does this compare to classicals?
Atypicals are more likely to cause weight gain (as opposed to classicals) and this can lead to diabetes, HTN, and hyperlipidemia
Patient taking an antipsychotic showed QT elongation. Which two drugs could be responsible? Which is more likely to cause ventricular arrhythmias and sudden death?
Ziprasidone
Thioridazine - more likely to lead to sudden death
Some antipsychotics can cause deposits in the cornea/lens and some in the retina. Name one drug that causes each
Cornea: chlorpromazine
Retina: thioridazine
Other than schizophrenia, name four other diseases antipsychotics can be used to treat
Bipolar (atypical)
Tourette’s
Huntingtons
Alzheimer’s
What is the antipsychotic drug of choice? Which drug is only used in refractory patients? Why?
Atypcials are DoC - Risperidone is most popular
Clozapine only used in refractory due to its ability to cause agranulocytosis
What is the only antipsychotic that is category B instead of category C?
Clozapine
