Drug Names
Antispsychotics associated with high risk of extrapyramidal effects
chlorpromazine, haloperidol
What is the MOA of antipsychotics
Bonus: which DA receptor
Dopamine antagonist
D2
what receptor usually causes the sedating effects seen in antipsychotics
H1
Name a condition where most antipsychotics are contraindicated
Parkinson's
A patient presents with hallucinations and delusions, it is later found the patient has bipolar disorder, what 3 classes of drugs are used for this condition.
Bipolar: lithium, antiepileptics, antipsychotics
antiepileptics: Na+ blockers e.g carbamezepine, valproate, lamotrigine
antipsychotics: atypicals/ haloperidol
Name the typical antipsychotics
CHLORPROMAZINE/ HALOPERIDOL
Some antipsychotics (chlorpromazine, haloperidol, clozapine, risperidone, quetiapine) can cause hypotension. By which receptor is this effect mediated?
Alpha 1 Block
Some antipsychotics have actions at mAchRs
Name 3 antimuscarinic effects
Bonus: which ones don't have effects at mAchRs (+100 per correct. 3 answers)
Blurred vision, urinary retention, confusion, dry mouth, constipation
no effect:
risperidone aripiprazole, haloperidol
term given to drugs where there is a small difference between the effective dose and the dose that produces toxic effects.
Narrow therapeutic window
A patient requires antipsychotics for his symptoms, he has tried most with no effect or improvement of symptoms, what antipsychotic should be prescribed?
bonus:what enzyme does clozapine interact with which may cause faster/slower metabolism
CLOZAPINE
CYP450
Partial agonist at D2 receptors
ARIPIPRAZOLE
How does action at 5HT2A receptors alleviate extrapyramidal side effects
facilitates DA release in mesocortical and nigrostriatal pathway
Name the 3 features of antipsychotic malignant syndrome
muscle rigidity, high temp, mental confusion
The psychiatrist wants to prescribe lithium but sees the patient is on a medication which may induce lithium toxicity if taken together. What did they likely spot?
bonus: what pother organ function may be affected by lithium
Diuretics ( they cause NA+ loss kidney compensates by increasing reabsorption of Na and lithium so may induce toxicity)
thyroid ( and kidney) 8.05 lecture
What can you give olanzapine with to treat bipolar
lithium or valproate
Name the 4 atypical antipsychotics
clozapine, risperidone, quetiapine, aripiprazole
What is the MOA of aripiprazole
partial agonist. decreases subcortical DA by competing for receptors AND increase DA in prefrontal cortex by agonising receptors.
A patient presents with sudden fever, sweats, malaise, and chills. PMH includes an antipsychotic. He missed his recent medication review and cannot remember the name of the drug. What antipsychotic is he likely on.
CLOZAPINE
A patient with a past history of MI requires antipsychotics. the psychiatrist explains the risk of LQTS due to the increased risk factors of the patient. What channels are affected by antipsychotics that increase the risk of LQTS and what is their function in the cardiac AP
K+ CHANNELS
REPOLARISATION
A 59 year old man has a diagnosis of Parkinson's. He has been taking co-careldopa and recently developed hallucinations. which antipsychotics would be most appropriate to prescribe
CLOZAPINE/ QUETIAPINE
A 42-year-old man with schizophrenia presents to A&E with rigidity, confusion, fever (39.5°C) and tachycardia. His CK is 8,000 U/L and creatinine is rising. He was started on a new antipsychotic 10 days ago for worsening paranoia. He developed marked hyperprolactinaemia after starting the medication. He has had significant extrapyramidal symptoms, including a resting tremor. This antipsychotic is a high-potency D2 blocker.
most likely drug?
Haloperidol
chlorpromazine also has EPS but haloperidol 50-100 x more potent
What are the effects of DA antagonists in the mesolimbic, nigrostriatal, and tuberoinfundibular pathways?
m: relieve hallucinations/ delusions
n: dystonia/dyskinesia
t:increase prolactin secretion
A patient develops a dangerous arrhythmia following his prolonged use of antipsychotics. What is the name of this arrhythmia and what ECG changes precede it
bonus: what other drug class can cause this
Torsades de Pointes (LQTS)
TCAs also have risk of long QT
A patient presents with hallucinations and delusions. He has a diagnosis of leaukemia The psychiatrist suggests an antipsychotic. which antipsychotic should NOT be prescribed
CLOZAPINE
A patient presents with a disorder characterized by TAU tangles and Amyloid-beta plaques. There is atrophy of hippocampus and entorhinal cortex. why would you want to avoid antipsychotics in this patient.
antimuscarinic effects
Alzheimers (dementia) cholinergic loss in this condition. AchEi used as one treatment option so you don't want to give drugs which oppose this effect.