Tox: antipsychotics

Question 1

Receptors targeted by antipsychotics

Answer 1

1) Dopamine receptors (non-specific)
2) Alpha-1 adrenergic antagonism
3) Muscarinic antagonism
4) Histamine antagonism
5) Cardiac Na Channels
6) Cardiac K channels

Question 2

SE caused by antipsychotics, based on receptor affected

Answer 2

1) dopamine: EPS, NMS
2) a1: hypoTN, reflex tachycardia
3) Muscarinic: anticholinergic symptoms
4) Histamine: sedation
5) Cardiac Na channels: QRS widening
6) Cardiac K channels: prolonged QTc

Question 3

Examples of typical vs atypical antipsychotics

Answer 3

Typical: haldol, chlorpromazine, loxapine
Atypical: risperidone, quetiapine, olanzapine, abilify (aripirazole)

Question 4

Potential adverse effect of clozapine

Answer 4

Blood dyscrasias -> agranulocytosis, leukopenia

Question 5

Symptoms and treatment of akathisia

Answer 5

Onset is hours to days, reversible.
Causes anxiety, acute motor restlessness.
Treatment: benzo, benadryl, benztropine

Question 6

Symptoms and treatment of acute dystonia

Answer 6

Onset hours-days after exposure to med, reversible.
SS: sustained muscle contractions such as grimacing, torticollis, trismus, laryngospasm, opisthotonos.

Tx: benzo, benadryl, benztropine

Question 7

Symptoms and treatment of antipsychotic induced parkinsonism

Answer 7

Takes days-months to develop. Usuall reversible.
Symptoms: akinesia, bradykinesia, masked facies, muscular rigidity, tremor, gait instability, cognitive impairment.

Tx: benztropine

Question 8

Symptoms and treatment of tardive dyskinesia

Answer 8

Months-years to develop.
Usually irreversible.
SS: involuntary, repetitive orofacial, trunk and extremity movements.
No specific treatments available.