Paliperidone belongs to the class of medications called antipsychotics. It is used to control the symptoms of schizophrenia and related psychotic disorders. Paliperidone works by readjusting the balance of chemicals in the brain that are involved in 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.

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 of 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.

For schizophrenia, the starting dose of paliperidone injectable suspension is 150 mg, injected intramuscularly (into a muscle) at the doctor's office. The second dose of 100 mg should be given 1 week after the first dose. After this, the recommended adult dose is 75 mg injected into a muscle once a month. Depending on how well the medication is tolerated and how well it works for you, your doctor may increase or decrease the dose.

For schizoaffective disorder, the starting dose of paliperidone injectable suspension is 150 mg, injected intramuscularly (into a muscle) at the doctor's office. The second dose of 100 mg should be given 1 week after the first dose. After this, the recommended adult dose is 50 mg to 150 mg injected into a muscle once a month. Depending on how well the medication is tolerated and how well it works for you, your doctor may adjust the dose.

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.

It is important to take this medication exactly as prescribed by your doctor. If you miss an appointment to receive a paliperidone injection, contact your doctor as soon as possible to reschedule your appointment. Store this medication at room temperature, protect it from moisture, and keep it out of the reach of children.

50 mg/0.5 mL
Each prefilled syringe containing a white-to-off-white, sterile, aqueous, prolonged-release suspension contains 50 mg of paliperidone (as 78 mg of paliperidone palmitate). Nonmedicinal ingredients: citric acid monohydrate, disodium hydrogen phosphate anhydrous, polyethylene glycol 4000, polysorbate 20, sodium dihydrogen phosphate monohydrate, sodium hydroxide, and water for injection.

75 mg/0.75 mL
Each prefilled syringe containing a white-to-off-white, sterile, aqueous, prolonged-release suspension contains 75 mg of paliperidone (as 117 mg of paliperidone palmitate). Nonmedicinal ingredients: citric acid monohydrate, disodium hydrogen phosphate anhydrous, polyethylene glycol 4000, polysorbate 20, sodium dihydrogen phosphate monohydrate, sodium hydroxide, and water for injection.

100 mg/1 mL
Each prefilled syringe containing a white-to-off-white, sterile, aqueous, prolonged-release suspension contains 100 mg of paliperidone (as 156 mg of paliperidone palmitate). Nonmedicinal ingredients: citric acid monohydrate, disodium hydrogen phosphate anhydrous, polyethylene glycol 4000, polysorbate 20, sodium dihydrogen phosphate monohydrate, sodium hydroxide, and water for injection.

150 mg/1.5 mL
Each prefilled syringe containing a white-to-off-white, sterile, aqueous, prolonged-release suspension contains 150 mg of paliperidone (as 234 mg of paliperidone palmitate). Nonmedicinal ingredients: citric acid monohydrate, disodium hydrogen phosphate anhydrous, polyethylene glycol 4000, polysorbate 20, sodium dihydrogen phosphate monohydrate, sodium hydroxide, and water for injection.

Do not take paliperidone if you:

• are allergic to paliperidone or any ingredients of the medication
• are allergic to risperidone

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

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.

• anxiety
• blurred vision
• breast swelling and sexual difficulties (men)
• cold-like symptoms (e.g., runny nose, nasal congestion, sneezing, sore throat)
• decreased alertness
• diarrhea
• dizziness
• drowsiness
• dry mouth
• fatigue
• flu-like symptoms (sudden lack of energy, fever, cough, sore throat)
• headache
• increased appetite
• increased saliva production
• injection site pain, swelling, or irritation
• itching
• joint stiffness
• lack of energy
• missed or irregular menstrual periods (women)
• muscle stiffness or spasm
• nasal congestion
• nausea
• nightmares
• restlessness
• sensations that the room is spinning
• skin rash
• slowness of movement
• stomach or abdominal pain
• tremor
• trouble sleeping
• vomiting
• weakness
• 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:

• abnormal heart rhythms such as fast or slow heart rate
• abnormal movements of the face or tongue
• blood pressure changes
• changes in body temperature, or feeling very hot and unable to cool down
• constipation (new or worsening)
• difficulty swallowing
• dizziness, especially when standing from a lying or seated position
• fainting
• inability to move or respond while awake
• irritability
• leakage of milk from breasts (women)
• palpitations
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of a blood clot in the arm or leg (tenderness, pain, swelling, warmth, or redness in the arm or leg) or lungs (difficulty breathing, sharp chest pain that is worse when breathing in, coughing, coughing up blood, sweating, or passing out)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• 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)
• symptoms of mania (e.g., decreased need for sleep, elevated or irritable mood, racing thoughts)
• skin rash
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• symptoms of low blood sugar (e.g., cold sweat, cool pale skin, headache, fast heartbeat, weakness)
• symptoms of a urinary tract infection (e.g., pain when urinating; urinating more often than usual; low back or flank pain; uncontrollable movement of the face, eyes, or body)
• uncontrolled twisting movements
• vaginal discharge
• vision changes

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

• complications of uncontrolled diabetes (e.g., shortness of breath, confusion, and loss of consciousness)
• muscle pain or achiness combined with very dark-coloured urine
• prolonged, continuous erection (an erection that lasts more than 4 hours)
• seizures
• signs of neuroleptic malignant syndrome (e.g., confusion, reduced consciousness, high fever, or muscle stiffness)
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• signs of severe skin reactions (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)
• sudden changes in mental state
• symptoms of a severe allergic reaction (e.g., itching; skin rash; shortness of breath; swelling of the face, lips, or tongue)
• symptoms of a stroke (e.g., sudden weakness or numbness of the face, arms, or legs – especially on one side; slurred speech; vision problems)

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.

Abnormal heart rhythms: This medication can cause abnormal heart rhythms. Certain medications (e.g., procainamide, amiodarone, sotalol, chlorpromazine, thioridazine, moxifloxacin) can increase the risk of a type of abnormal heart rhythm called QT prolongation and should not be used in combination with paliperidone. People who have a slow heart rate, low potassium or magnesium levels, or have congenital prolongation of the QT interval are more at risk for this type of abnormal heart rhythm and its complications. Talk to your doctor about the risks and benefits of using this medication.

Blood clots: Rarely, this medication increases 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. 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.

Blood counts: This medication can decrease the number of neutrophils (a type of white blood cell that helps fight infection), red blood cells (which carry oxygen), and platelets (which help your blood to clot). Your doctor will do blood tests to monitor this. If you notice any signs of infection (e.g., fever, chills, or sore throat) or unusual bleeding or bruising, contact your doctor immediately.

Body temperature: This medication, like other antipsychotic medications, can disrupt the body's ability to control body temperature. People who exercise vigorously, who are exposed to extreme heat, are dehydrated, or are taking anticholinergic medications (e.g., benztropine, oxybutynin) are more at risk. Contact your doctor as soon as possible if you feel very hot and are unable to cool down while taking this medication.

Cataract surgery: During eye surgery for cataracts, people who take or have taken paliperidone 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 paliperidone.

Cholesterol: Paliperidone can cause increased blood cholesterol levels. If you are at risk of developing high cholesterol or you have high cholesterol levels before starting paliperidone, 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.

Diabetes and blood sugar: Paliperidone may cause an increase in blood sugar levels 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.

If you experience weakness, increased thirst, increased urination, and increased appetite while taking this medication, contact your doctor.

Drowsiness/reduced alertness: Paliperidone may affect the mental or physical abilities needed to drive or operate machinery. Avoid driving, operating machinery, or performing other hazardous tasks until you have determined how this medication affects you.

Gastrointestinal problems: Paliperidone should not be taken by people with conditions associated with narrowing of the gastrointestinal tract (e.g., esophagus disorders, inflammatory bowel disease, "short gut" syndrome, cystic fibrosis), or by people who have difficulty swallowing.

Heart conditions: If you have a heart condition, such as angina, heart failure, irregular heartbeat, or 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.

Hypersensitivity syndrome: A severe allergic reaction called hypersensitivity syndrome has occurred for some people taking medications similar to paliperidone. This reaction involves a number of organs in the body and may be fatal if not treated quickly. Stop taking the medication and get immediate medical attention if you have symptoms of a severe allergic reaction, including fever, severe rash, swollen glands, yellowing of the skin or eyes, or flu-like symptoms with skin rash or blistering.

Lactose intolerance: Certain strengths (3 mg tablets) of paliperidone tablets are prepared with lactose. If you have hereditary lactose or galactose intolerance problems you should not take this strength of the medication.

Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function or kidney 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.

Low blood pressure: Paliperidone may cause low blood pressure when rising from a sitting or lying down position. If you feel dizzy, lightheaded, or feel your pulse racing, call your doctor. While you are taking this medication, get up slowly after you have been sitting or lying down for a prolonged period.

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

Parkinson's disease: People with Parkinson's disease or dementia with Lewy bodies (DLB) may be at an increased risk of NMS (see warning about NMS), as well as other side effects associated with paliperidone. Talk to your doctor about the risks and benefits of using this medication.

Risperidone: People who are taking risperidone should not take paliperidone at the same time. These medications are related, and taking them together may cause an increased risk of side effects.

Seizures: Paliperidone may increase the risk of seizures, especially in people who have had seizures in the past. People who are at risk of seizures who take this medication should be closely monitored by their doctor. If you have had 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 agitated behaviour: People taking this medication may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. These symptoms may occur within several weeks after starting this medication. 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): TD, a syndrome consisting of potentially irreversible, involuntary, repetitive movements of the face and tongue muscles, may develop in people who take certain antipsychotic medications including paliperidone. 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 you experience muscle twitching or abnormal movements of the face or tongue, contact your doctor as soon as possible.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. Using this medication during the last three months of pregnancy can harm the developing baby and cause withdrawal symptoms after birth. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and taking paliperidone, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 18 years of age. Clinical studies using paliperidone to treat adolescents with schizophrenia have shown an increased likelihood of movement disorders occurring in this group.

Seniors: Medications similar to paliperidone can increase the risk of death as a result of a stroke,  mini-stroke, and severe infection, when used to treat seniors with dementia. Paliperidone should not be used to treat seniors with dementia.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other 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.

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.