Risperidone is used to treat schizophrenia (an illness that causes changes in perception, thoughts and behaviour). It helps to relieve symptoms common in schizophrenia, such as distorted thinking and emotional instability.
This medicine may also be used on its own or together with other medicines to treat other mood disturbances such as bipolar disorder (mood changes between feeling very high and very low).
Risperidone injection is to be given intramuscularly (into the muscles, usually in the arm or buttocks).
Your doctor or nurse will administer the injection for you.
The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on your condition and response to the medication.
Your doctor may advise you to continue taking oral risperidone or another oral medication for mood disorders for 3 weeks after your first injection.
It is important that you continue with your treatment even when you feel well. Do not stop from receiving your injections suddenly as this may worsen your condition.
Ensure that you keep all appointments with your doctor so that you do not miss any doses. Your doctor also needs to regularly monitor your response to Risperidone.
If you miss an appointment or miss an injection, alert your doctor or nurse. A replacement appointment or injection should be given as soon as possible.
Inform your doctor if you have the following conditions:
- heart disease e.g. conduction abnormalities, prior heart attack
- diseases affecting the blood vessels and blood supply to the brain
- low white blood cell count or history of drug-induced blood disorders
- other types of dementia (group of symptoms affecting thinking and social abilities)
- Parkinson's disease (a disorder that affects movement of a person, causing symptoms such as tremors, muscle stiffness, slowed movement and impaired balance or walking)
- history of fits or seizures including those at risks of seizures e.g. head trauma, brain damage, alcoholism
- diabetes or other disorders of glucose regulation
- at risk of orthostatic hypotension (fall in blood pressure when standing up from a sitting or lying down position), suicidal ideation, or aspiration pneumonia (a type of lung infection)
- previous high prolactin levels in the blood or possible tumours dependent on prolactin
- liver disease
- kidney disease
Let your doctor know if you are pregnant or breastfeeding.
Risperidone may affect the ability of your body to adjust to temperature changes in the environment. Avoid exposure to very cold or very hot environments. Avoid strenuous exercise and activities like going to the sauna. Drink more water to prevent dehydration.
Individual's genetic traits are unique from each other. Researchers say that certain genetic traits can affect the response to this drug. Though not routinely done, in some exceptional cases, your doctor may advise you to take genetic testing to check if this drug is best suited for you.
Why is it important to keep my appointments with the doctor?
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
- Routine tests (e.g. blood count, electrolytes, renal and liver function, fasting blood glucose level, fasting lipid panel, eye examination) may be done while you are being treated with this medicine.
- Regular monitoring of blood pressure, weight, height, body mass, and waist circumference may be needed.
- Monitoring of any changes in menstruation, libido, erectile problems, or abnormal involuntary movements may also be necessary.
Your doctor will advise you about how often you need to have these tests.
Risperidone may cause dizziness, drowsiness, and blurred vision. If affected, do not drive or take part in any activity in which you need to be alert or need to see clearly.
Other side effects include any of the following: headache, tiredness, nausea, vomiting, stomach pain or discomfort, diarrhoea, indigestion, dry mouth, toothache, muscle pain or spasm, joint pain, difficulty sleeping, weight gain, and changes in appetite.
This medicine may cause your blood pressure to fall suddenly when you get up from a sitting or lying down position and you may feel giddy. To minimise this problem, stand up slowly.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- fast or irregular heartbeat
- chest pain
- fever, confusion, change in thinking, excessive sweating
- muscle stiffness, uncontrolled muscle movements of your body or face such as sticking out of the tongue, smacking of the lips
- rashes, breathlessness, swelling of the face, eyes or mouth
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicines for irregular heartbeat e.g. quinidine
- medicines to treat depression e.g. fluoxetine, paroxetine
- rifampicin (medicine to treat TB [infection known as tuberculosis])
- medicines for epilepsy (fits or seizures) e.g. phenytoin, phenobarbital
- medicines to treat fungal infections e.g. itraconazole
- medicines for Parkinson's disease e.g. levodopa
- medicines for high blood pressure
- other medicines for mood disorders
This list does not include all medicines that may interact with Risperidone.
Always notify your doctor or pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
Avoid alcohol.
Store in the refrigerator, between 2-8°C, or below 25°C (up to 7 days before administration). Do not freeze Risperidone otherwise, it will no longer be effective and should not be used.
Protect from light.
Medicines must not be used past the expiry date.
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