S15C174 - Antipsychotics

Question 1

Antipsychotics - pathophys

Answer 1

• all bind to presynaptic and postsynaptic dopamine 2 receptors, leading to dopamine blockade
• D2 does antipsychotic effects and antiemetic effects and hyperprolactinemia, gynecomastia and EPS symptoms
• alpha1-adrenergic R’s causes orthostatic HoTN and reflex tachy
• antagonism of muscarinic receptors cuses anticholinergic sx
• blockade of histminergic R’s causes sedation
• hepatic metabolism

Question 2

EPS symptoms

Answer 2

• from D2 receptor blockade in basal ganglia
• dystonia, akathisia, parkinsonism, NMS
• potentially irreversible: perioral tremor, tardive dyskinesia
• acute dystonia: hyperkinetic mvmt, uncoordinated involuntary contractions of face, tongue, neck, trunk, extremities (tongue protrusion, grimace, trismus, oculogyric crisis, opisthotonus)
• parkinsonism: cogwheel rigidity, pill-rolling tremor, mask facies, shuffling gait, bradykinesia, akinesia, cognitive impairment

Question 3

Tx of acute dystonia/akathisia

Answer 3

-diphenhydramine or benztropine or benzos x2d

Question 4

NMS

Answer 4

• Sx: fever, muscle rigidity (lead-pipe and cogwheel), AMS, diaphoresis, tremor, tachy, labile BP, incontinent
• tetrad: fever, rigidity, autonomic dysfxn, AMS
• antipsychotic w/in past 7d, new med or change in dose

-tx: dantrolene, airway mgmt

Question 5

Antipsychotic OD

Answer 5

-CNS depression, sedation, ataxia, dysarthria, confusion, respiratory depression, sinus tach, porlonged PR/QRS/QT

• tx: supportive, tx seizures with benzos, MgSO4 if long QT
• free of toxicity if: no change in mental status, pulse, GP, orthostatic HoTN or long QT after 6h post ingestion