Psychosis and therapeutics

Question 1

Why is clozapine still used despite the it being withdrawn in other countries

Answer 1

• Deemed better than 1st generation anti-psychotics
  -When patients stop it, they get worse
  >Other drugs don’t work as effectively on these pt
  -Better than chlorpromazine
• There have been 20 studies conducted vs 1st gen and it had been proven to be more effective.

Question 2

what receptors does clozapine have greater affinity to that other 1st generation anti-psychotics do

Answer 2

5-HT2

Question 3

what percentage of clozapine enters into the system unchanged

Answer 3

27-50%

Question 4

What factors affect the plasma concentration of clozapine

Answer 4

Smoking
hepatic metabolism
gastric absorption
Age
gender

Question 5

How long does it take for a steady state plasma concentration of clozapine to be reached

Answer 5

7-10 days

Question 6

In which patients is clozapine’s usually used

Answer 6

In unresponsive schizophrenia patients

Psychosis in Parkinson’s disease

Question 7

What is the usual dose of clozapine in unresponsive schizophrenia patients

Answer 7

200-450mg daily with a max of 900mg per day

Question 8

What is the usual dose of clozapine in Parkinson’s psychosis patients

Answer 8

25 - 37.5mg once daily and can be increased to max of 50mg

Question 9

What are some potential adverse reactions of clozapine

Answer 9

-Neutropenia
-(POTENTIALLY) agranulocytosis
-Myocarditis
-Cardiomyopathy

Question 10

What are some medicine optimisation issues that can occur with clozapine

Answer 10

ongoing blood testing in chronic schizophrenic pts

Smoking

Caffeine consumption

Drug interactions

formulations

Cardiovascular cautions

Myelosuppressive drugs