Antipsychotics

Antipsychotic medications explained


Psychosis is a condition caused by any one of a number of illnesses – for example, schizophrenia or bipolar mood disorder – that affect the brain and cause the person to lose contact with reality. During a psychotic episode, the person may experience delusions, hallucinations and thought disturbances. Antipsychotic medications work to minimise these symptoms.

How antipsychotic medications work
Medical research has shown that symptoms of psychosis are associated with changes in brain chemistry. Antipsychotic medications help to restore the brain’s natural chemical balance, thereby reducing or getting rid of the psychotic symptoms. It can take some weeks before the medication starts to work.

Antipsychotic medications help control symptoms
Although antipsychotic medications cannot cure mental illnesses, they are effective in eliminating or reducing psychotic symptoms such as delusions, hallucinations and thought disorders.

After the psychotic episode has passed
Maintenance doses of an antipsychotic medication are important to minimise the risk of further psychotic episodes. If a person suddenly stops taking antipsychotic medication against their doctor’s advice, it can lead to a return of psychotic symptoms.

Common side effects
Common side effects of antipsychotic medications include:

Drowsiness
Weight gain
Loss of menstrual periods in women
A drop in blood pressure when standing up, which can cause dizziness
Stiffness or trembling in muscles.
Other possible side effects include:
Constipation
Fluid retention
Sexual dysfunction
Dry mouth
Headaches.
It is important to remember that the same medication can affect different people in different ways. Not everyone will have the same unwanted side effects.

Side effects should be discussed with the doctor
Side effects can be worrying to a patient. Any side effects should be discussed immediately with the treating doctor. They can be minimised by changing the dose, changing the medication prescribed, prescribing another form of medication, or simply changing the time of day the medication is taken. Weight gain can also be managed with advice about diet and exercise.

Tardive dyskinesia
Tardive dyskinesia refers to involuntary movements that appear in a minority of people who have been taking an antipsychotic medication for a long time. These movements usually involve the mouth and the tongue, although other parts of body may also develop movements.

Tardive dyskinesia may be masked by the antipsychotic medication, and may only appear when medication is discontinued or the dose is reduced. Tardive dyskinesia does not respond to antiparkinsonian medication (medication to treat the neurological disorder parkinsonism). The best way to avoid tardive dyskinesia is to use the lowest dose of antipsychotic medication possible.

The new generation of antipsychotic medications
In recent years, a new generation of antipsychotic medications has become available. They have fewer side effects but are as effective as, or more effective than, the older antipsychotic medications.

The new medications are:
Amisulpride – may be prescribed for people with schizophrenia.
Aripiprazole – may be prescribed for people with schizophrenia.
Clozapine – may be prescribed for people with schizophrenia whose symptoms are not sufficiently helped by other antipsychotic medications.
Olanzapine – may be prescribed for people with schizophrenia or bipolar disorder.
Quetiapine – may be prescribed for people with schizophrenia or with acute mania associated with bipolar disorder.
Risperidone – may be prescribed for people with schizophrenia and related psychoses.
There is also some evidence that these medications are more effective against the ‘negative’ symptoms of psychosis, such as social withdrawal, loss of drive and lack of emotional expression.

How long before these medications start to work?
People prescribed amisulpride, olanzapine, quetiapine or risperidone may see some benefits within six weeks. If the drug is not working, the doctor may consider adjusting the dose or replacing it with a different medication. About one-third of people taking clozapine will see some benefit within six weeks. For others, it may take up to 12 months to see benefits.

People taking clozapine need regular blood tests
About three per cent of people who use clozapine experience a fall in white blood cell numbers. White blood cells are needed to fight infection. People taking clozapine need regular blood tests to determine if this effect is occurring. If tests show white blood cells are falling, the taking of clozapine is immediately stopped.

Clozapine can also cause:
Sleepiness
Weight gain
Constipation
Low blood pressure
A fast or irregular heart beat.
At high doses, clozapine can cause epileptic seizures. If this happens, the doctor may prescribe anti-epileptic medication or lower the clozapine dose.