Typical Antipsychotics

Question 1

Mechanism of action for typical antipsychotics

Answer 1

D2 receptor antagonism

Muscarinic, histaminic, and adrenergic antagonism

Question 2

What does dopamine blockade in the 4 dopamine pathways do?

Answer 2

Mesolimbic = reduce positive symptoms (delusions, hallucinations)
Mesocortical = worsen negative symptoms (avolition, cognitive symptoms)
Nigrostriatal = causes EPS (akathisia, dystonia, parkinsonism)
Tuberoinfundibular = causes hyperprolactinemia

Question 3

High potency typical antipsychotics

Answer 3

Haloperidol (Haldol)
Fluphenazine (Prolixin)
Pimozide (Orap)
Thiothixine (Navane)
Trifluoperazine (Stelazine)

Question 4

Mid potency typical antipsychotics

Answer 4

Perphenazine (Trilafon)
Loxapine (Loxitane)
Molindone (Moban)

Question 5

Low potency typical antipsychotics

Answer 5

Chlorpromazine (Thorazine)
Mesoridazine (Serentil)
Thioridazine (Mellaril)

Question 6

Minor side effects of typicals

Answer 6

Hyperprolactinemia - gynecomastia, impotence, amenorrhea, sexual dysfunction
Anticholinergic - dry mouth, constipation, blurry vision, confusion, urinary retention
Prolonged QTC
Anti-histamine - sedation
Anti-adrenergic - orthostatic hypotension
Weight gain
Dermatitis/photosensitivity

Question 7

Serious side effects of typicals

Answer 7

EPS
Tardive dyskinesia
NMS

Question 8

Treatment for EPS

Answer 8

Akithisia - propranolol, lorazepam, benztropine
Dystonia - benadryl, benztropine, lorazepam
Parkinsonism - benztropine, amantadine, propranolol

Question 9

Treatment for tardive dyskinesia

Answer 9

Decrease dose of antipsychotic
Start clozapine
OR, vit E and behavioral therapy

Question 10

Treatment for NMS

Answer 10

IVF, cooling blankets
dantrolene - muscle relaxant
bromocriptine and amantidine = dopamine agonists

Question 11

High potency vs low potency

Answer 11

High potency = lower drug dose, more EPS, less muscarinic/histaminergic/adrenergic
Low potency = higher drug dose, less EPS, worst muscarinic/histaminergic/adrenergic = sedating, orthostatic hypotension (don’t give in eldery for hip fx). Significant QT prolongation! Possibly retinitis pigmentosa at large doses