How it works
What does risperidone do?
There is a naturally occurring chemical messenger ('neurotransmitter') in the brain called dopamine.
Dopamine is a chemical messenger in the brain mainly involved with thinking, emotions, behaviour and perception.
In some illnesses there may be too much dopamine, and this causes some of the symptoms of the illness.
Risperidone blocks the effects of dopamine in the brain, resulting in a reduction of the symptoms.
Risperidone also has effects on other neurotransmitters in the brain, such as serotonin, and its beneficial effects may be related to this as well.
How long does risperidone take to work?
It can take four to six weeks for risperidone to have its full effect, but some people get good effects right from the first week.
You should stay in touch with your doctor to see how it goes over the first few weeks. They might do some tests to check your symptoms.
If you have had no good effects after two to three weeks, your doctor may increase the dose or change the medicine.
Your doctor will start with a low dose, which they will increase slowly to a dose that is effective for you. This may take several days or weeks.
If you are starting on the long-acting injection, it takes three weeks for the injection to start releasing the risperidone.
This means you will need some other antipsychotic cover. This could be risperidone tablets or your previous antipsychotic.
The injection provides a constant release of risperidone over two weeks, so injections are given every two weeks. The three-week delay in the injection starting to release risperidone only matters when you first start treatment. Think of the injection having a very long fuse wire.
If you were already on some other tablets, you will need to continue with them for those first few weeks on the injection.
If you were not on other tablets, the doctor will probably give you some risperidone tablets until the injection starts to work.
If you were on another depot or long-acting injection, you may have one dose of each, very close together.
Don’t worry – as explained above you will not overdose while you take both types for those first few weeks.
How long do I need to take risperidone?
You and your doctor should talk about how long you need to take risperidone.
If you take risperidone for bipolar disorder or schizophrenia, you should think about taking it for a few years, otherwise your old symptoms can come back.
Young people taking risperidone for conduct disorders will usually only take it for six weeks.
Your doctor needs to know if...
You need to talk to your doctor or pharmacist before starting treatment with risperidone if any of the following apply to you:
- you have any heart problems
- you have epilepsy
- you have diabetes
- you have had a blood clot, or anyone in your family has had one
- you have ever had unusual movements of your tongue, mouth or face
- you have kidney or liver problems
- you or someone in your family has had a stroke or is at risk of a stroke
- you have ever had a condition known as neuroleptic malignant syndrome (NMS) whose symptoms include high temperature, muscle stiffness and sweating
- you have a condition called porphyria (ask your doctor – if you have it, it should be on your records)
- you have ever had an erection that lasted for more than a few hours and was very painful (priapism)
You should only take risperidone as agreed with your doctor
You will get most benefit from your risperidone if you take it regularly at the dose prescribed by your doctor.
Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.
Risperidone is usually taken once or twice a day. You will start with a low dose, which will be increased slowly to a dose that is effective for you. This may take several days or weeks.
It doesn’t matter what time you take it each day - choose a time that you can always remember and get into a routine. This could be a mealtime, or when you brush your teeth.
Risperidone can be taken with or without food.
For the normal coated tablets, swallow them whole with a drink of water - if you chew them, they taste bitter. You can break them into two pieces at the line on the tablet if you have trouble swallowing them as one piece.
For the orodispersible tablets (melts), put it on your tongue and let it dissolve there and then swallow it (you can wash down with water if needed).
You can dilute the oral solution with any other non-alcoholic drink if it makes it nicer to take, apart from a cup of tea or a glass of cola (the tannin chemical in tea and cola stops the risperidone from absorbing properly into your body).
If you agree to have the long-acting injection (LAI), a doctor or nurse will inject this into a muscle in your arm or bottom every two weeks. The good thing about this is that you don’t have to remember to take your medicine every day. It is slowly working in your body all the time between injections.
The injection should switch between the left side (arm or buttock) and the right side (arm or buttock) so that it’s not given in the same place all the time.
What if I miss a dose?
If you remember later during the day, take it as soon as possible.
If you forget to take it by your next dose, just take the next dose at the correct time. Do not try to catch up on missed doses.
Do not take a double dose.
If you miss your appointment for your injection, contact your doctor straight away to make another appointment.
It is very important to have the injection every two weeks.
What will happen if I forget to take my risperidone?
If you forget to take your tablets for a few days, or you miss an injection, you may start getting your old symptoms back. You should talk to your doctor about this.
Stopping the use of risperidone
Stopping the medication causes the balance of chemicals in the brain to alter.
When you start taking an antipsychotic, your brain adjusts to having lower levels of dopamine around.
If you stop taking the antipsychotic suddenly, the balance starts to change again, and your brain can take a while to adapt to this change. You could get your old symptoms back. You could also get some symptoms from the change, which are called withdrawal symptoms, although these are mild and rare with risperidone.
You will probably get your old symptoms back if you stop risperidone suddenly.
If you are thinking of stopping or want to stop, talk to your doctor and they can help.
They will reduce and stop the risperidone slowly so that any problems (like your old symptoms coming back) can be picked up quickly.
It is better to agree stopping with a doctor who will reduce your dose gradually. This will be done over a few weeks.