Risperdal (risperidone)

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How does it work?

Risperdal tablets, liquid and quicklets all contain the active ingredient risperidone, which is a type of medicine known as an atypical antipsychotic.

Risperidone works in the brain, where it affects various neurotransmitters, in particular dopamine and serotonin (5HT). Neurotransmitters are chemicals that are stored in nerve cells and are involved in transmitting messages between the nerve cells.

Dopamine and serotonin are neurotransmitters known to be involved in regulating mood and behaviour, amongst other things. Psychotic illness is considered to be caused by disturbances in the activity of neurotransmitters (mainly dopamine) in the brain. Schizophrenia is known to be associated with an overactivity of dopamine in the brain, and this may be associated with the delusions and hallucinations that are a feature of this disease.

Risperidone works by blocking the receptors in the brain that dopamine acts on. This prevents the excessive activity of dopamine and helps to control schizophrenia.

Schizophrenic patients may experience 'positive symptoms' (such as hallucinations, disturbances of thought, hostility) and/or 'negative symptoms' (such as lack of emotion and social withdrawal). Risperidone is effective in relieving both positive and negative symptoms of schizophrenia, whereas the conventional antipsychotics are usually less effective against the negative symptoms.

Risperidone also relieves 'affective symptoms' that are associated with schizophrenia, such as depression, guilt feelings or anxiety.

Risperidone is used by specialists to treat episodes of mania in people with the psychiatric illness, bipolar affective disorder (manic depression).

Risperidone can be taken as Risperdal liquid, conventional Risperdal tablets or Risperdal quicklets. Risperdal quicklets are tablets that are designed to dissolve on the tongue and be swallowed with the saliva, without the need for water.

For the treatment of schizophrenia, risperidone can also be given as a depot injection that lasts for two weeks. See the link to Risperdal consta at the end of this factsheet for more information.

What is it used for?

- Psychotic illness such as schizophrenia.
- Manic episodes of manic depression.

Warning!

- Risperdal quicklets should be placed in the mouth where they rapidly dissolve in your saliva for easy swallowing. The quicklets are fragile and should not be pushed through the foil as this will damage them. Open the blister by pulling up the edge of the foil and peeling it off, then tip the tablet out. The quicklet should be taken as soon as you have opened the blister as it cannot be stored once removed.
- Follow the instructions that are supplied with Risperdal liquid for measuring a dose carefully. Risperdal liquid may be diluted with mineral water, orange juice or black coffee. When diluted in this way, the product should be used immediately. Risperdal liquid should not be mixed with tea.
- This medicine may cause drowsiness. If affected do not drive or operate machinery. Alcohol should be avoided.
- Unless your doctor tells you otherwise, you should not suddenly stop taking this medicine, even if you feel better and think you don't need it any more. This is because the medicine controls the symptoms of the illness but doesn't actually cure it. This means that if you suddenly stop treatment your symptoms could come back. Stopping the medicine suddenly may also rarely cause withdrawal symptoms such as sweating, nausea, vomiting, difficulty sleeping or tremor. When treatment with this medicine is stopped, it should be done gradually, following the instructions given by your doctor.
- This medicine can occasionally cause your blood pressure to drop when you move from a lying down or sitting position to sitting or standing, especially when you first start taking the medicine. This may make you feel dizzy or unsteady. To avoid this try getting up slowly. If you do feel dizzy, sit or lie down until the symptoms pass.
- This medicine can cause some people to put on weight. Talk to your doctor about this before you start treatment so that you can discuss strategies, such as diet and exercise, for minimising any weight gain.
- Consult your doctor immediately if you experience any abnormal movements, particularly of the face, lips, jaw and tongue, while taking this medicine. These symptoms may be indicative of a rare side effect known as tardive dyskinesia, and your doctor may ask you to stop taking this medicine, or decrease your dose.
- Consult your doctor immediately if you experience the following symptoms while taking this medicine: high fever, sweating, muscle stiffness, faster breathing and drowsiness or sleepiness. These symptoms may be due to a rare side effect known as the neuroleptic malignant syndrome, and your treatment may need to be stopped.
- This medicine is not recommended for treating behavioural problems or psychoses associated with dementia, due to an increased risk of stroke in this group of patients. The use of this medicine to treat acute psychoses in patients with a history of dementia should be limited to short-term use only and should be under specialist advice.

Use with caution in

- Elderly people
- Liver disease
- Kidney disease
- Disease involving the heart and blood vessels
- High blood pressure
- Irregular heartbeat caused by very rapid contraction of the top two chambers of the heart (atrial fibrillation)
- History or risk of stroke or small temporary strokes
- Smokers
- Diabetes
- Epilepsy
- Parkinson's disease.

Not to be used in

- Breastfeeding.
- Risperdal quicklets contain aspartame and should not be taken by people with an inherited disorder of protein metabolism called phenylketonuria.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

- The safety of this medicine in pregnancy has not been established. It should therefore be used with caution during pregnancy, and only if the potential benefits to the mother outweigh any possible risks to the foetus. Seek medical advice from your doctor.
- This medicine passes into breast milk and women taking this medicine should therefore not breastfeed. Seek medical advice from your doctor.

Label warnings

- This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.

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