Antipsyhotics

Question 1

What is the mechanism of action of clozapine?

Answer 1

1. Dopamine antagonist: High affinity for D4 (to a lesser extent D1, D2, D3, D5)
2. Serotonin antagonist: 5HT2A
3. Seratonin partial agonist: 5HT1A (may explain reduction of negative symptoms)
4. Muscarinic M1, M2, M3, M5, histamine, and alpha-1 adrenergic-receptor antagonist

Question 2

What is the mechanism of action of olanzapine?

Answer 2

1. Dopamine antagonist
2. Serotonin antagonist: 5HT2

Question 3

What is the mechanism of action of quetiapine?

Answer 3

1. Dopamine antagonist: weak D2 antagonist
2. Serotonin antagonist: potent 5HT2A antagonist
3. Also blocks H1 (very sedating)

Question 4

What is the mechanism of action of risperidone?

Answer 4

1. Dopamine antagonist: High affinity for D2 (this high affinity means risk of EPS at high doses)
2. Serotonin antagonist: 5HT2A

Question 5

What is the mechanism of action of aripiprazole?

Answer 5

1. Dopamine partial agonist: D2
2. Seratonin partial agonist: 5HT1A
3. Seratonin antagonist: 5HT2A

Question 6

What is the mechanism of action of amisulpride?

Answer 6

Selective dopamine antagonist: D2/D3

Question 7

What is the mechanism of action of lurasidone?

Answer 7

1. Dopamine antagonist: D2 antagonist
2. Serotonin antagonist: 5HT2A, 5-HT7
3. Adrenoceptor antagonist: alpha2A- and alpha2C
4. Seratonin partial agonist: 5HT1A
   …
   (lurasidone does not bind to histaminergic or muscarinic receptors)

Question 8

What is the mechanism of action of paliperidone?

Answer 8

Active metabolite of risperidone; similar D2/5-HT2A antagonism

Question 9

What is the mechanism of action of ziprasidone?

Answer 9

1. Dopamine antagonist: D2
2. Serotonin antagonist: 5HT2A
3. Seratonin agonist: 5HT1A
4. Inhibitis 5-HT/NE reuptake

Question 10

What is the mechanism of action of haloperidol?

Answer 10

Dopamine antagonist: potent D2 antagonist

Question 11

What is the mechanism of action of chlorpromazine?

Answer 11

1. Dopamine antagonist: D2
2. H1, M1, and α1 antagonist (more sedative and anticholinergic)

Question 12

What is the mechanism of action of flupentixol?

Answer 12

Dopamine antagonist: potent D2 antagonist

Question 13

What is the mechanism of action of perphenazine?

Answer 13

Dopamine antagonist: D2

Question 14

What is the mechanism of action of zuclopenthixol?

Answer 14

Dopamine antagonist: D2
…
(available in depot form)