Antipsychotics

Question 1

What are the positive symptoms of schizophrenia and what are the linked to?

Answer 1

Mesolimbic pathway

• Hallucinations and delusions
• Thought disorder
• Perceptual disturbances
• Incongruous mood
• Increased motor function

Question 2

What are the negative symtpoms of schizophrenia and what are they linked to?

Answer 2

Mesocortical pathway

• Blunted affect
• Poverty of speech
• Diminished motivation
• Social withdrawal

Question 3

What are the cognitive symptoms of schizophrenia?

Answer 3

• Deficits in memory and cognitive control of behaviour

Question 4

What are the 4 well-defined dopamine pathays in the brain and what are they responsible for?

Answer 4

• Mesolimbic: blockade of D2 will decrease positive symptoms
• Nigrostriatal: blockade of D2 may lead to disorders of movement (EPRs)
• Mesocortical: blockade of D2 may cause of worsen negative and cognitive symptoms
• Tuberoinfundibular: blockade of dopamine receptors will increase prolactin levels

Question 5

What are the classical antipsychotic drugs, MOA, and distinguish HP from LP?

Answer 5

MOA: block D2 in mesolimbic pathway

• Fluphenazine - HP
• Haloperidol - HP
• Chlorpromazine - LP; AE deposits in cornea/lens
• Thioridazine - LP; AE retinal deposits

Question 6

What are the atypical antipsychotics and MOA?

Answer 6

• Clozapine: higher afinity for D1, D4, 5HT2, muscarinic, alpha-andrenergic, and lower D2; least likely EPR; AE agranulocytosis
• Risperidone: blocks 5HT2 more than D2
• Olanzapine
• Aripiprazole: partial D2 and 5HT1A agonist, 5HT2A antagonist; DOC
• Quetiapine: least likely EPR

Question 7

Which drugs are antiemetic and why?

Answer 7

MOA: blockade of D2 receptors of chemoreceptor trigger zone of medulla

• All except Aripiprazole and Thioridazine

Question 8

What do EPRs include and how are they treated?

Answer 8

• Parkinsonism: antimuscarinic like Benzotropine or Trihexyphenidyl with Diphenhydramine or Amantadine
• Dystonia: Benzotropine, Trihexyphenidyl, or Diphenhydramine
• Akathisia: reduce/stop antipsychotic and/or Clonazepam or Propanolol
• Tardive diskynesia: reduce/stop antipsychotic and VMAT inhibitor Terabenazine or Valbenazine; Benzodiazepine may help; Clozapine if need antipsychotic

Question 9

What can be used for neuroleptic malignant syndrome?

Answer 9

• Dantrolene (muscle relaxer)
• Bromocriptine (ergoline derivative)