Risperidone belongs to the group of medications known as antipsychotic agents. This medication is used to treat schizophrenia. Schizophrenia can cause symptoms such as hallucinations (e.g., hearing, seeing, or sensing things that are not there), delusions, unusual suspiciousness, and emotional withdrawal. People with this condition may also feel depressed, anxious, or tense.

Medications like risperidone are thought to work by correcting the function of nerve pathways in certain areas of the brain.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The dose of risperidone varies according to needs and the condition being treated.

For adults with schizophrenia, the dose is usually started at 1 mg to 2 mg per day (given either once or twice per day) and increased slowly over several days to 4 mg to 6 mg per day. Lower doses are often used for people with low blood pressure, kidney problems, or liver disease. The safety of risperidone has not been established beyond a maximum dose of 16 mg per day (8 mg given twice daily).

For seniors with schizophrenia, the dose is usually 0.25 mg given twice daily to a maximum daily dose of 3 mg.

For behavioural problems in people with severe Alzheimer type dementia, the usual starting dose is 0.25 mg twice a day. This dose is slowly increased every 2 to 4 days to a usual dose of 1 mg per day (0.5 mg twice a day). This dose may be increased to a maximum of 2 mg per day (1 mg twice a day).

For adults with mania associated with bipolar disorder, risperidone should be taken once daily, starting with 2 mg or 3 mg daily. This dose may be increased to a maximum of 6 mg daily.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Risperidone can be taken with or without meals. Swallow the tablets with some water or other fluid.

Oral dissolving tablets should be left in the foil packaging until you are ready to take a dose. Place the tablet on the tongue, where it will begin to dissolve and can then be swallowed, with water if necessary.

Measure the oral solution using the pipette that is included with the medication. This gives a more accurate measurement than a household teaspoon. Mix the medication with 100 mL of water, coffee, orange juice or low-fat milk. It should not be taken with cola or tea.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store risperidone at room temperature in a dry place (not the bathroom), protect it from light, and keep it out of the reach of children.

Do not take this medication if you are allergic to risperidone or any ingredients of the medication.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• back pain
• constipation
• drowsiness
• eye irritation
• mild injection site reactions (e.g., pain, itching, swelling)
• muscle spasms or stiffness
• restlessness
• unusual tiredness
• weight changes

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• anxiety
• dizziness when rising from a sitting or lying position
• flu-like symptoms (e.g., sudden lack of energy, fever, cough, sore throat)
• inability to move or respond while awake
• increased cholesterol (fats) in the blood
• infection of the lungs (pneumonia; e.g., fever or chills, shortness of breath, fatigue, chest pain, cough)
• infection of the urinary tract (e.g., pain when urinating, urinating more often than usual, low back or flank pain)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• movement disorders (e.g., continuous muscle spasms and contractions; slow movements; irregular, jerky movements; tremor; inability to move eyes; increased blinking; puffing of cheeks; shuffling walk; muscle twitching; spasms or abnormal movements of the face, neck, or body; rigid muscles)
• severe injection site reactions (e.g., severe bruising, sores, infection, lumps under the skin)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• signs of muscle damage (e.g., unexplained muscle pain, tenderness or weakness, or brown or discoloured urine)
• skin rash
• slowed movements
• sudden loss of vision
• symptoms of a blood clot (e.g., swelling, pain and redness in an arm or leg, sudden chest pain, difficulty breathing, or pounding heartbeat)
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• tremor
• trouble speaking or swallowing
• twisting movements of the body

Stop taking the medication and seek immediate medical attention if any of the following occur:

• an erection that lasts more than 4 hours without sexual stimulation
• signs of diabetic ketoacidosis (e.g., difficulty breathing, extreme thirst, vomiting, nausea, loss of appetite, confusion, unusual tiredness)
• seizures
• signs of neuroleptic malignant syndrome (e.g., confusion, reduced consciousness, high fever, or muscle stiffness)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• signs of a stroke:
• sudden weakness or numbness in the face, arms, or legs (often on one side of the body)
• speech problems
• vision problems
• balance problems or dizziness
• confusion
• sudden severe headache with no known cause
• symptoms of a severe allergic reaction such as hives; itching; difficulty breathing; or swelling of the face, mouth, tongue, or throat
• symptoms of inflammation of pancreas:
• severe abdominal pain
• fever
• nausea and vomiting

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood clots: This medication may increase the chance of blood clot formation, causing reduction of blood flow to organs or the extremities.

If you have a history of clotting you may be at increased risk of experiencing blood clot-related problems such as heart attack, stroke, or clots in the deep veins of your leg. If you experience symptoms such as sharp pain and swelling in the leg, difficulty breathing, chest pain, blurred vision or difficulty speaking, contact your doctor immediately.

Body temperature regulation: Risperidone can cause body temperature changes. If you are taking this medication, you should take precautions when there is a risk of exposure to extreme heat or cold, strenuous exercise, or dehydration, or if you are also taking anticholinergic medication. Discuss with your doctor about how to prevent body temperature issues.

Cataract surgery: During eye surgery for cataracts, people who take or have taken risperidone are at risk for developing a condition called Intraoperative Floppy Iris Syndrome (IFIS). This condition can lead to eye damage. If you are planning to have an operation on your eye, inform your doctor if you are taking or have taken risperidone.

Diabetes: Risperidone may cause an increase in blood sugar levels (may cause a loss of blood glucose control) and glucose tolerance may change. People with diabetes may find it necessary to monitor their blood sugar more frequently while using this medication.

If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Cholesterol: Risperidone can cause increased blood cholesterol levels. If you are at risk of developing high cholesterol or you have high cholesterol levels before starting risperidone, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Drowsiness/reduced alertness: Risperidone may interfere with activities requiring mental alertness. People taking this medication should not drive or operate machinery until they are reasonably certain that risperidone does not affect their ability to carry out these activities safely.

Heart conditions: If you have a heart condition such as angina, heart failure, or irregular heartbeat, and if you have had a heart attack, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Heart rhythm: Risperidone has been linked to changes to the normal rhythm of the heart, including an irregular heartbeat called QT prolongation. QT prolongation is a serious life-threatening condition that can cause fainting, seizures, and sudden death. If you are at risk for heart rhythm problems (e.g., people with heart failure, angina, low potassium, or magnesium levels), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Hypersensitivity reaction: In rare cases, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS syndrome) may occur. This reaction involves symptoms including fever, swollen glands, yellowing of the skin or eyes, flu-like symptoms with skin rash or blistering, or other organ involvement. These reactions are medical emergencies. Get immediate medical attention if you have symptoms of a severe allergic reaction. If you experience any unusual symptoms, contact your doctor.

Kidney problems: Decreased kidney function or kidney disease can cause this medication to build up in the body, causing increased side effects. If you have kidney problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver problems: Decreased liver function may cause increased side effects with risperidone. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Low blood pressure: Risperidone may cause a lowering of blood pressure when rising from a sitting or lying position, or a racing heart rate, especially during the few weeks of treatment. If you feel dizzy or lightheaded or feel your pulse is racing, and this feeling does not go away after a few minutes, call your doctor. Because this medication can cause dizziness or light-headedness, do not get up too quickly after you have been sitting or lying for prolonged periods.

Low white blood cells: Risperidone may cause a decrease in the number of white blood cells in your body. This decrease makes it harder for your body to fight infections. If you have a history of low white blood cells or are on medication (e.g., chemotherapy) that can cause low white blood cells, monitor for any signs of fever or infection and seek medical attention if symptoms occur.

Neuroleptic malignant syndrome (NMS): Risperidone, like other antipsychotic medications, can cause a potentially fatal syndrome known as neuroleptic malignant syndrome (NMS). If you notice the symptoms of NMS, get immediate medical attention. Symptoms include high fever, muscle stiffness, confusion or loss of consciousness, sweating, racing or irregular heartbeat, and fainting.

Parkinson's disease: Risperidone may cause deterioration in the condition of people with Parkinson's disease. Parkinson's disease may also cause an increased risk of experiencing Neuroleptic Malignant Syndrome (NMS). If you have Parkinson's disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Seizures: Risperidone may increase the risk of seizures, especially in people who have had seizures in the past. If you have a seizure disorder or a history of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Suicidal or self-harm behaviour: People taking this medication may feel agitated or may want to hurt themselves or others. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately. You should be closely monitored by your doctor for emotional and behaviour changes while taking this medication.

Tardive dyskinesia (TD): This syndrome consists of potentially irreversible, involuntary, and repetitive movements of the face and tongue muscles that may develop in people who take certain antipsychotic medications. Although TD appears most commonly in seniors (especially women), it is impossible to predict who will develop TD. The risk of developing TD increases with higher doses and long-term treatment. If signs and symptoms of TD develop during treatment with risperidone, contact your doctor as soon as possible.

Weight gain: With long-term treatment, weight gain (averaging 2.3 kg) has occurred in those who take this medication.

Pregnancy: The safety of risperidone for use during pregnancy has not been established. Risperidone should not be used during pregnancy unless the expected benefits outweigh the potential risks. If you become pregnant while taking risperidone, contact your doctor immediately.

Breast-feeding: Risperidone passes into breast milk. People should not breast-feed while taking risperidone.

Children and adolescents: The safety and effectiveness of risperidone have not been established for use by children and adolescents under 18 years of age.

Seniors: Adults over 65 years of age were not included in testing for this medication. With other forms of this medication, there appears to be a higher risk of strokes, heart attacks, and other serious side effects. Talk to your doctor about the risks and benefits of using this medication.

There may be an interaction between risperidone extended-release injection and any of the following:

• abiraterone acetate
• acetylcholinesterase inhibitors (e.g., donepezil, galantamine, neostigmine, pyridostigmine, rivastigmine)
• aclidinium
• alcohol
• aliskiren
• alpha blockers (e.g., doxazosin, terazosin, tamsulosin)
• alpha agonists (e.g., clonidine, methyldopa)
• amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
• angiotensin converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
• angiotensin receptor blockers (ARBs; e.g., candesartan, irbesartan, losartan)
• antiarrhythmics (e.g., amiodarone, dipyridamole, disopyramide, dronedarone, flecainide, procainamide)
• antihistamines (e.g., azelastine, cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine, rupatadine)
• antiparkinson medications (e.g., amantadine, apomorphine, bromocriptine, levodopa, pramipexole, ropinirole, rotigotine)
• antipsychotics (e.g., cariprazine, chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine)
• apalutamide
• atropine
• "azole" antifungals (e.g., fluconazole, itraconazole, ketoconazole, voriconazole)
• barbiturates (e.g., butalbital, phenobarbital)
• benzodiazepines (e.g., alprazolam, clonazepam, diazepam, lorazepam)
• benztropine
• beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
• botulinum toxin
• brimonidine
• buprenorphine
• bupropion
• butorphanol
• cabergoline
• caffeine
• calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
• cannabis
• capecitabine
• carvedilol
• CF transmembrane regulators (e.g., ivacaftor, lumacaftor, tezacaftor)
• chloral hydrate
• cinacalcet
• clidinium
• cobicistat
• conivaptan
• cyclosporine
• dantrolene
• darifenacin
• diabetes medications (e.g., acarbose, canagliflozin, gliclazide, liraglutide, insulin, metformin, sitagliptin)
• dimenhydrinate
• diphenoxylate
• diuretics (water pills; e.g., furosemide, hydrochlorothiazide, indapamide, triamterene)
• domperidone
• efavirenz
• eliglustat
• eluxadoline
• entacapone
• enzalutamide
• eplerenone
• esketamine
• etravirine
• fesoterodine
• flibanserin
• flunarizine
• general anesthetics (medications used to put people to sleep before surgery)
• glucagon
• glycopyrrolate
• guanfacine
• hepatitis C antivirals (e.g., glecaprevir, ledipasvir, velpatasvir)
• hydralazine
• certain HIV protease inhibitors (e.g., atazanavir, darunavir, lopinavir, ritonavir, tipranavir)
• ipratropium
• kava kava
• ketotifen
• lemborexant
• linezolid
• lithium
• macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
• methadone
• methylphenidate
• metoclopramide
• mifepristone
• minocycline
• mirabegron
• mirtazapine
• modafinil
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
• muscle relaxants (e.g., baclofen, cyclobenzaprine, methocarbamol, orphenadrine)
• nabilone
• narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone, tapentadol, tramadol)
• nirmatrelvir and ritonavir
• nitrates (e.g., nitroglycerin, isosorbide dinitrate)
• olopatadine
• ondansetron
• oxybutynin
• peginterferon alfa-2b
• perampanel
• pomalidomide
• potassium supplements
• protein kinase inhibitors (e.g., crizotinib, dasatinib, nilotinib, sunitinib)
• pregabalin
• propiverine
• prucalopride
• quinine
• quinolone antibiotics (e.g., levofloxacin, moxifloxacin)
• rifabutin
• rifampin
• riociguat
• sacubitril
• St. John's wort
• seizure medications (e.g., clobazam, carbamazepine, levetiracetam, phenobarbital, phenytoin, primidone, rufinamide, topiramate, valproic acid)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline, vortioxetine)
• serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
• sodium phosphate
• solifenacin
• spironolactone
• terbutaline
• terbinafine
• tetrabenazine
• thalidomide
• theophyllines (e.g., aminophylline, theophylline)
• tiotropium
• tizanidine
• tolterodine
• trazodone
• tretinoin
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
• trospium
• tryptophan
• umeclidinium
• zolpidem
• zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.