Side effects of antipsychotics

Antipsychotics have a wide range of side effects. The most widely researched include:

Sedation
Sedation (drowsiness) is a common side-effect of antipsychotics. The antipsychotics that cause the most sedation include chlorpromazine, promazine, thioridazine, clozapine and zotepine. Often this can be dealt with by taking your medication at night just before you go to bed. If feeling sedated is a problem for you, contact your doctor as they may be able to reduce the dose or change your medication.

Movement disorders
Movement disorders are very common with the typical antipsychotics. There are different types of movement disorder. These include:

Dystonia - prolonged muscle spasms often involving the face, neck, shoulders and upper limbs. Drugs such as procyclidine and orphenadrine are given to treat dystonia.

Akathisia - fidgety movements of the legs which may be accompanied by a strong sense of inner restlessness and unease. This often means that a person cannot sit comfortably, and may be driven to walk up and down to try and gain relief. It is best treated with clonazepam or propranolol.

Parkinsonian movement disorders - involve stiffness and shakiness, and resembles the unrelated condition of Parkinson's disease. The limbs move slowly and muscles of the face may be quite immobile, producing an expressionless, staring face. Rhythmic shaking may occur but is not usually very severe, and is most obvious in the hands. Procyclidine and orphenadrine, amongst other drugs, are given to treat Parkinsonian movement disorders.

Tardive dyskinesia - major signs of the condition are excessive movement of the lips, tongue and jaw, (known as oro-facial dyskinesia). The term "tardive" means delayed or late-appearing and this reflects the fact that treatment may have gone on for some months or years before the movement disorder becomes apparent. Oro-facial dyskinesia is the most common form of tardive dyskinesia. Other abnormal movements are seen including jerky, abrupt movements of the limbs and body, but these are less common.

It may be that people with schizophrenia tend to develop odd movements but may be especially susceptible when taking antipsychotic drugs. The control and planning of movement is a function of certain areas of the brain. If schizophrenia is thought of as a disease of the brain rather than of the mind, it can be understood why movement is so commonly disturbed in people with schizophrenia.

A strategy that may lessen early signs of tardive dyskinesia is to lower the dose or stop the antipsychotic drug. Disappearance of the movements is more likely among younger patients. On withdrawing antipsychotic drugs, any signs of existing tardive dyskinesia usually first worsen and then improve. The most promising strategy for reducing the risk of tardive dyskinesia is the use of atypical antipsychotics.

Olanzapine has been shown to cause less tardive dyskinesia than haloperidol. Such a benefit may also be seen with other atypicals such as risperidone.

Tardive dyskinesia is extremely rare with clozapine. In fact, many people who have symptoms of tardive dyskinesia improve slowly when given clozapine. There is some evidence of benefit with tetrabenazine (Nitoman); but this drug has its own fairly frequent, serious side-effects such as drowsiness and depression.

Vitamin E may help in some people and has few side-effects.

Heart problems
A number of antipsychotic drugs can cause physical damage to the heart in some people, although this side effect is less common. The strongest association is between clozapine and inflammation and thickening of the heart muscle. But associations are also found between this kind of heart damage and other antipsychotics including chlorpromazine, fluphenazine, haloperidol and risperidone and with the mood stabiliser lithium. More research is needed to determine why this association between heart damage and some antipsychotic medications exists for some people.

It may be that the lifestyle of people with psychosis is a risk factor and that the drugs themselves are not causing the problem. It may be that the drugs do cause the problem in some way which is not yet understood. Alternatively it may be that some other disease process accounts for the damage.

As well as causing physical damage to the heart some antipsychotics can lead to abnormalities in the rhythm of the heart. In a few cases the abnormality in heart rhythm can lead to serious problems including, in some cases, death. It is thought that the older (typical) antipsychotics are more likely to cause this than the newer (atypical) drugs. Again, more research is needed to see if the drugs themselves cause the heart problems or whether the lifestyle of people on the drugs accounts for it. For instance, many people with severe mental illness smoke, which also puts people at risk of heart disease.

Weight gain
Weight gain is one of the most difficult problems for people taking antipsychotics. This does not mean that everyone using antipsychotics will put on weight, or that there is nothing which can be done about the problem. Weight gain is often a problem for people on thioridazine, clozapine, olanzapine and zotepine.

Weight gain often means that the person concerned loses confidence and self-esteem, a problem often ignored by doctors. Excessive weight gain may also have a bad effect on general health, and may cause someone with mental health problems to stop their medication, with unhappy results. If you feel that weight gain is having a detrimental effect on you, discuss this with your doctor, they may be able to reduce the dose or change your medication. Alternatively they may be able to help you change to a good diet and an increase in activity.

Diabetes
Several recent studies have shown that there is an increased risk of diabetes with antipsychotic medication. If the antipsychotics are responsible, there could be three reasons for this increased risk: 

• the antipsychotic drug could be unmasking some increased risk for diabetes, perhaps by triggering the condition in someone who has a predisposition to develop diabetes 
• the antipsychotic could be causing weight gain and so stimulating an increased risk for diabetes 
• the antipsychotic could be the direct cause of the diabetes.

So far the evidence is unclear as to which one of these three possibilities is most likely.

The main symptoms of diabetes include; 

increased thirst, going to the toilet all the time - especially at night, extreme tiredness, weight loss, genital itching or regular episodes of thrush, blurred vision

If you begin to suffer from any of these you are advised to contact your doctor. They may be able to lower your dose or change your medication.