Clozapine Flashcards
What is it?
Clozapine is one of the ‘newer antipsychotic’ drugs used to treat symptoms of
schizophrenia in people who have not done well on at least two other similar drugs
How does it work?
Dopamine is the chemical messenger mainly involved with thinking, emotions, and behaviour.
In schizophrenia, it may be overactive which helps to produce some of thesymptoms of the illness.
The main effect that clozapine has is to block some of the dopamine in the brain, reducing the effect of having high levels, and reducing the symptoms caused by too much dopamine.
Blood tests
Clozapine can upset the blood of about two or three in every hundred peopletaking it.
It can reduce the number of white cells or neutrophils in the blood.
This makes it much harder for your body to fight infections.
The patients must, therefore, have regular blood tests for as long as you are taking this medicine.
Monitoring
Regular blood testing is the main form of monitoring. You will have a blood test every week for at least 18 weeks. After 18 weeks all your blood results will be reviewed, and if all is well, testing may change to every second week until the end of the first year of treatment.
The risk of neutropenia decreases after the first year of
treatment.
So if your blood tests have been satisfactory, you should be able to transfer to testing every four weeks.
Testing will then continue every four weeks for as long as you are taking clozapine
Duration of treatment
This is very difficult to tell, as people’s responses are different.
However, you will probably need to continue your treatment for several years.
Long-term treatment should be reviewed every three to six months or sooner if there are problems.
It is likely that you will benefit from clozapine by taking it for many years.
Benefits
About 6 out of 10 people will benefit from taking clozapine. Some do very well and
others will be a bit better
You will not become worse from trying it
Disadvantages
It can take several months for an effect to be seen
There are several side effects- drowsiness, Constipation, hypotension, Hyper
salivation, fever and palpitations. To keep these unwanted effects to a minimum, we will
start you on a low dose and increase it slowly
Neutropenia
One of the more serious side effects is that it can reduce the number of white cells or neutrophils in the blood, resulting in a condition called neutropenia.
This makes it much harder for your body to fight infections.
On higher dosage, it can also induce a seizure or
a fit.
Warning signs: If you think you have a cold, sore throat or any other infection, tell your
doctor or nurse immediately. They will arrange a blood test to check your white cell
count. If your white cell count is normal you should be able to continue with your
treatment, but your doctor will tell you if this is the case
