Anti-psychotics

Question 1

Clozapine is atypical (2nd generation) drug that is a core anti-psychotic drug. It is generally used as a last line drug treatment for psychosis, when up to 2 other drugs, one of which must have been an atypical drug have already been tried. What is the mechanism of action of Clozapine?

Answer 1

• antagonist for dopamine receptors

- serotonin 5HT2A antagonist

Question 2

Clozapine is atypical (2nd generation) drug that is a core anti-psychotic drug. It is generally used as a last line drug treatment for psychosis, when up to 2 other drugs have already been tried. Clozapine has 2 mechanisms:

1 - antagonist for dopamine receptors
2 - serotonin 5HT2A antagonist

Why is the a dopamine antagonist good for treating psychosis?

Answer 2

• able to inhibit where dopamine levels are high such as in mesolimbic system that causes positive symptoms

Question 3

Clozapine is atypical (2nd generation) drug that is a core anti-psychotic drug. It is generally used as a last line drug treatment for psychosis, when up to 2 other drugs have already been tried. Clozapine has 2 mechanisms:

1 - antagonist for dopamine receptors
2 - serotonin 5HT2A antagonist

Why is the antagonist serotonin 5HT2A receptors good for treating psychosis?

Answer 3

• clozapine is a dopamine receptor antagonist, and when it binds it increases dopamine levels
• but in other parts of the brain antagonist of serotonin 5HT2A receptors causes an increase in dopamine, which is good for negative symptoms and the nigrostriatal pathway

Question 4

Clozapine is atypical (2nd generation) drug that is a core anti-psychotic drug. It is generally used as a last line drug treatment for psychosis, when up to 2 other drugs, one of which must have been an atypical drug have already been tried. Clozapine is an effective anti-psychotic, by acting as an antagonist for dopamine and serotonin 5HT2A receptors, but there are 2 serious adverse events that it can cause, what are they?

Answer 4

• constipation, which can ultimately kill patients

- neutropenia (low neutrophils)

Question 5

Aripiprazole is a core anti-psychotic drug that is first line treatment for psychosis. What is the mechanism of action of Aripiprazole?

Answer 5

• partial agonist of dopaminergic receptors

- antagonist of 5HT2A serotonin receptors

Question 6

Aripiprazole is a core anti-psychotic drug that is first line treatment for psychosis. It has 2 mechanisms of action:

1 - partial agonist of dopaminergic receptors
2 - antagonist of 5HT2A serotonin receptors

Why is this combination of mechanisms a good treatment option for psychosis?

Answer 6

• antagonist of 5HT2A serotonin receptors causes increased dopamine release
• partial agonist of dopaminergic receptors controls how much dopamine binds post-synaptically (not too much or too little, so good for all round effects of psychosis)

Question 7

Aripiprazole is a core anti-psychotic drug that is first line treatment for psychosis. It has 2 mechanisms of action:

1 - partial agonist of dopaminergic receptors
2 - antagonist of 5HT2A serotonin receptors

When would this drug generally be prescribed?

Answer 7

• first line for someone who has never had a psychotic episode

Question 8

Chlorpromazine is a member of the typical (1st generation) anti-psychotic medications. What is the mechanism of action for this drug?

Answer 8

• dopamine antagonist of post-synapse

- good for positive psychotic episodes

Question 9

Haloperidol is a typical (1st generation) anti-psychotic medication. What is its mechanism of action?

Answer 9

• dopamine antagonist of post-synapse

- good for positive psychotic episodes

Question 10

Risperidone is an atypical (2nd generation) anti-psychotic medication. What is its mechanism of action?

Answer 10

1 - antagonist for dopamine receptors

2 - serotonin 5HT2A antagonist

Question 11

Risperidone is an atypical (2nd generation) anti-psychotic medication. Risperidone has 2 mechanisms:

1 - antagonist for dopamine receptors
2 - serotonin 5HT2A antagonist

Why is the antagonist of serotonin 5HT2A receptors and dopamine receptors good for treating psychosis?

Answer 11

• inhibits dopamine receptors where dopamine is already high, that may cause positive symptoms
• increase dopamine release by inhibiting serotonin 5HT2A receptors, so good for negative symptoms and nigrostriatal pathway where dopamine may be low