Risperidone

You should start to feel some benefits in the first one to two weeks, but it can take four to six weeks for risperidone to have its full effect. This can vary between individuals and the reason why you are taking risperidone.

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 seen no change in any symptoms after one or two weeks, you should talk to your doctor about your progress. They may recommend increasing the dose or changing your medicine. Don’t increase your dose yourself if you think the medication isn’t working.

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, you may need to continue taking risperidone orally for a few weeks, but this varies depending on the brand of injection you are prescribed. Your doctor or pharmacist will explain this.

If you have responded well to risperidone and you switch to a long-acting injection instead of tablets or liquid, it is likely you will be prescribed a long-acting injection of a medicine called paliperidone. After you take risperidone, your body changes it to paliperidone, so while it may seem like your medicine has changed, it actually hasn’t.

Risperidone may cause weight loss or weight gain, but weight gain is more common. The risk of weight gain with risperidone is lower compared to other antipsychotic medicine (like olanzapine), but children and young people appear to be more at risk of this side effect compared with adults. You may also be more likely to gain weight if you have not taken this type of medication before.

It is not possible to predict how risperidone will affect each person before they start taking it. Talk to your doctor or pharmacist if you are concerned about your weight (or changes to your weight) while taking risperidone. They can review your medicine with you and look at any changes that could be made to help.

Your doctor will monitor your weight regularly when you are taking risperidone.

Making sure you do enough exercise and eat a healthy diet (with vegetables and fibre) can help you to avoid putting on too much weight.

Mental health conditions like schizophrenia and bipolar disorder can make being active and eating healthily more of a challenge. Talk to your doctor, pharmacist and specialist healthcare team for lifestyle advice and where to get support if this would be helpful.

If you do gain weight, most of this is likely to occur in the first six months of treatment. It is possible you may continue to gain weight after this time, but the rate of weight gain will usually be slower. This can happen even if you are taking a very low dose.

Risperidone can also affect the way your body processes sugar. A side effect of risperidone includes high blood sugar and, while not common, has been linked to the development or worsening of diabetes in some young people. This could also be linked to putting on weight.

It is important to watch out for symptoms that might mean your body is having trouble processing sugar. These include wanting to drink a lot, going for a wee a lot, and feeling very weak or tired all the time. If you develop these symptoms, or any other symptoms you are concerned about, it is important to make an appointment with your doctor to discuss this.

If you already have diabetes, taking risperidone may affect your blood sugar levels. Talk to your doctor and check your blood glucose levels regularly if this applies to you. You may have to increase the medication you use for your diabetes.

You may want to let your family and friends know you are taking risperidone so they can support you and help you look out for side effects.

You can feel sleepy in the first few days of taking risperidone. This should get better after the first week or two. With risperidone, some people find it hard to get to sleep. If this happens, try taking it earlier in the day and see if this makes it easier to get to sleep.

Reported side effects of risperidone include strange dreams or nightmares.

Rarely, risperidone can also cause sleep-talking and sleep-walking. Some people have also done other activities while they were asleep, like eating.

If you are on the long-acting injection, talk to your doctor if your sleep is disturbed.

If you have been taking risperidone for more than a month and you continue to feel very sleepy during the day or you are struggling to get to sleep (or your sleep at night is worse), you should go back to your doctor and discuss what changes could be made to help. This may include switching to a different medication.

Alcohol

It may be possible to drink some alcohol in moderation while taking risperidone but the two together might make you feel very sleepy and unsteady on your feet, especially when you first start taking the medication.

During the first few weeks of treatment, it is recommended that you don’t drink alcohol until you know how the medicine affects you.

If you want to drink alcohol, it’s best to only drink small amounts, and have a plan for getting home safely if you go out.

Drinking alcohol every day, or in large amounts, can make your symptoms worse and may mean you won’t get the maximum benefit from your medication.

Street drugs

Some street drugs like cocaine and ecstasy can increase levels of dopamine in the brain. As antipsychotics block the effects of dopamine, the 'high' from street drugs may not be as 'high' as before. You may therefore be tempted to increase the dose of your street drug to make up for it, but this could be dangerous.

Cannabis and other drugs may have their own side effects on your mental health, like anxiety or psychosis.

Some street drugs can make you feel sleepy and this could be made worse with risperidone.

There are many other street drugs, but we don’t know what effect taking them with risperidone will have, so it’s best to be cautious. There is no regulation of street drugs or ‘legal highs’, so even if there are no known issues with the medication you take, the supply you receive might be mixed with other substances that could be dangerous.

Risperidone can produce a false positive test for LSD on a urine drug screen. Talk to your doctor about this if it is a problem for you.

Get more advice on our drugs and alcohol guide.

Risperidone does not mix well with some other medicines, including herbal remedies.

Tell your doctor before you take risperidone if you are taking any other medicines, including things you have bought over the counter and things you put on your skin.

Look at the leaflet inside your medicine box for more information about other medicines that can interact with risperidone. With some medicines your doctor may need to adjust the dose of your medicines if you take them together. Ask a doctor or pharmacist for more information if you have any questions.

There are multiple companies that manufacture this medicine and the non-active ingredients may vary between products and also between the different strengths of tablets that are available. Always let your pharmacist know if you have any food allergies or intolerances, and always check with them if you’re concerned about any of the ingredients in your medication.

The ordinary tablets may not be suitable for you if you have problems eating some sugars or dairy foods, as they contain lactose.
The orodispersible ('melt in your mouth') tablets may contain aspartame, which can be a problem for people who have a condition called phenylketonuria.

If you need to avoid animal products, please note that non-active ingredients used in the production of medicines may sometimes be of animal origin. Ask your pharmacist if you have any questions about the ingredients.

Further information about practical considerations for medicines if you need to avoid animal products can be found on the Vegan Society website.

Taking risperidone may make you feel tired or dizzy and may affect your eyesight when you start taking it.

This could affect you if you drive a car, ride a bike, or do anything else that needs a lot of focus. It might be best to stop doing these things for the first few days or weeks, until you know how it affects you.

Most people drive as normal while taking risperidone. If you are worried about this or have any concerns you would like to discuss, speak to your doctor or pharmacist.

You must tell The DVLA (Driver and Vehicle Licensing Agency) if you have bipolar disorder, schizophrenia, schizoaffective disorder or other mental health conditions that could affect your driving. You can be fined if you do not tell The DVLA about a medical condition that affects your driving and may be prosecuted if you are involved in an accident as a result.

Pregnancy

If you become pregnant while you are on risperidone, you should carry on taking it and make an appointment to see your doctor as soon as possible. They can discuss the benefits and risks of continuing risperidone and help you to make a decision that is best for you and your baby.

They may refer you to a specialist perinatal mental health team to support you with this decision.

You can find out more information about taking risperidone during pregnancy at Bumps (Best Use of Medicines in Pregnancy).

Untreated illness can also be harmful to you and your developing baby, so decisions about stopping or avoiding medication when you are pregnant need to be discussed carefully with your doctor. If you and your doctor agree that it is best for you to continue taking risperidone while pregnant, you should tell your midwife. If you are planning to get pregnant, it is recommended that you take folic acid while you are trying for a baby and during pregnancy. It is safe to take this together with risperidone.

A rare side effect of taking risperidone is that it can increase your chance of getting blood clots. Let your doctor know if you’re taking risperidone and they might suggest a medicine to prevent this.

Post-natal

If risperidone is taking in the last few months of pregnancy, it can cause some symptoms in newborn babies. These are usually mild and last a short amount of time. Speak to your doctor or midwife if your baby is restless, has feeding or breathing problems or is very sleepy.

Breastfeeding

Risperidone is passed to the baby in breastmilk in small amounts.
If your baby was born early, then breastfeeding while you are taking risperidone may not be recommended. Talk to your midwife and doctor about feeding options.

If you breastfeed while taking risperidone, seek urgent medical advice if your baby becomes restless, very sleepy or develops feeding problems.

Sex

Risperidone can have side effects that affect your sex life. These include:

• painful erections, or problems getting an erection and ejaculating
• irregular or stopped periods
• some bleeding from the vagina, and problems reaching orgasm
• some breast growth and milk flow, regardless of gender
• lower sex drive

In rare cases, risperidone can cause a long-lasting and painful erection, called priapism. If this happens to you, go to a hospital for medical treatment.

Untreated illness can have a negative effect on your sex life, so if risperidone helps you to recover, positive effects can include improving your desire, experience and enjoyment of sex as your mood lifts and you become interested in life and relationships again.

Fertility

There is currently no evidence to suggest that risperidone will affect your fertility.

It can increase a naturally occurring hormone in your body called prolactin. If you have raised levels of prolactin this can impact your fertility, no matter your gender. For people who menstruate, it may cause your periods to stop or become irregular. This can make getting pregnant harder.

Let your doctor know if you’re planning on getting pregnant and taking quetiapine. They can monitor your prolactin levels.

Risperidone is not a banned substance in sport.

Most people play sports as normal while taking risperidone. However, it may affect your ability to play sports that require a lot of focus. It might be best to stop these sports for the first few days until you know how it affects you or the effects get better.

If you have any concerns, discuss this with your doctor.

Risperidone may affect your concentration, give you blurred eyesight and make you feel dizzy and tired. Psychosis and schizophrenia themselves can also affect concentration.

Ideally it’s best not to take risperidone for the first time just before your exams.

It is not possible to predict how the medication will make you feel, and if you do get any side effects, these are more likely to occur when you first start taking risperidone.

You should talk to your doctor about any future exams if you are starting risperidone. You might decide together to delay starting it until you have done them.

If they are more than a month away, however, you might find that it is better to start risperidone to improve your motivation and ability to study.

Most people take exams as normal while taking risperidone. If you are worried that taking risperidone might make studying for or taking your exams harder, discuss this with your doctor.