How does it work?
Invega tablets contain the active ingredient paliperidone, which is a type of medicine called an atypical antipsychotic.
Paliperidone works in the brain, where it affects various neurotransmitters, in particular dopamine and serotonin (5HT). Neurotransmitters are chemicals that are stored in nerve cells and are involved in transmitting messages between the nerve cells.
Dopamine and serotonin are neurotransmitters known to be involved in regulating mood and behaviour, amongst other things. Psychotic illness is considered to be caused by disturbances in the activity of neurotransmitters (mainly dopamine) in the brain. Schizophrenia is known to be associated with an overactivity of dopamine in the brain, and this may be associated with the delusions and hallucinations that are a feature of this disease.
Paliperidone works by blocking the receptors in the brain that dopamine acts on. This prevents the excessive activity of dopamine and helps to control schizophrenia.
Schizophrenic patients may experience 'positive symptoms' (such as hallucinations, disturbances of thought, hostility) and/or 'negative symptoms' (such as lack of emotion and social withdrawal). Paliperidone is effective in relieving both positive and negative symptoms of schizophrenia, whereas older antipsychotics are usually less effective against the negative symptoms.
Paliperidone also relieves 'affective symptoms' that are associated with schizophrenia, such as depression, guilt feelings or anxiety.
Invega tablets are prolonged-release tablets. They are designed to release the paliperidone slowly and continuously to help provide steady blood levels of the medicine over 24 hours. These tablets must not be broken, crushed or chewed, as this would damage the prolonged-release action.
What is it used for?
- Treatment of psychotic or manic symptoms of schizoaffective disorder.
How do I take it?
- Invega tablets should be swallowed whole with liquid, in the morning. They must not be broken, chewed or crushed.
- The tablets can be taken either before or after breakfast, but it is important to stick to a set routine of either before or after breakfast, as otherwise the amount of medicine absorbed into the blood from the gut may fluctuate.
- If you forget to take a dose you should not take a double dose to make up for it. Just take your next dose as usual.
- Unless your doctor tells you otherwise, you should not suddenly stop taking this medicine, even if you feel better and think you don't need it any more. This is because the medicine controls the symptoms of the illness but doesn't actually cure it. This means that if you suddenly stop treatment your symptoms could come back. When treatment with this medicine is stopped, it should be done gradually, following the instructions given by your doctor.
- The active ingredient in Invega tablets is released slowly as the tablets pass through the gut. The shell of the tablets may pass through your gut undigested and be visible in your faeces. This is normal and nothing to worry about.
- This medicine may cause drowsiness or dizziness. If affected do not drive or operate machinery. You should avoid drinking alcohol while taking this medicine because it is likely to make any drowsiness worse.
- This medicine can occasionally cause your blood pressure to drop when you move from a lying down or sitting position to sitting or standing, especially when you first start taking the medicine. This may make you feel dizzy or unsteady. To avoid this try getting up slowly. If you do feel dizzy, sit or lie down until the symptoms pass.
- This medicine can cause some people to put on weight. Talk to your doctor about this before you start treatment so that you can discuss strategies, such as diet and exercise, for minimising any weight gain.
- Antipsychotic medicines can sometimes affect the ability of the body to control its core body temperature. This is more likely to be a problem in elderly people and can result in heat stroke in hot temperatures and hypothermia in cold temperatures. It is important to avoid situations that can result in you overheating or getting dehydrated. Ask your doctor or pharmacist for more advice.
- This medicine may rarely cause a decrease in the normal amounts of blood cells in the blood. For this reason you should consult your doctor immediately if you experience any of the following symptoms: unexplained bruising or bleeding, purple spots, sore throat, mouth ulcers, high temperature (fever), feeling tired or general illness. Your doctor may want to take a blood test to check your blood cells.
- Antipsychotic medicines are associated with an increased risk of getting a blood clot in a vein (deep vein thrombosis) or in the lungs (pulmonary embolism). For this reason, you should consult a doctor immediately if you get any of the following symptoms, which could suggest you have a blood clot: stabbing pains and/or unusual redness or swelling in one leg, pain on breathing or coughing, coughing up blood or sudden breathlessness.
- Consult your doctor immediately if you experience any abnormal movements, particularly of the face, lips, jaw and tongue, while taking this medicine. These symptoms may be indicative of a rare side effect known as tardive dyskinesia, and your doctor may ask you to stop taking this medicine, or decrease your dose.
- Consult your doctor immediately if you experience the following symptoms while taking this medicine: high fever, sweating, muscle stiffness, faster breathing and drowsiness or sleepiness. These symptoms may be due to a rare side effect known as the neuroleptic malignant syndrome, and your treatment may need to be stopped.
Use with caution in
- Elderly people.
- Severely decreased liver function.
- Decreased kidney function.
- Diabetes. (If you have diabetes your blood sugar levels should be monitored closely while you are having treatment with this medicine, because it may increase your blood sugar.)
- People with disease involving the heart and blood vessels (cardiovascular disease) for example heart failure, angina or previous heart attack.
- People with a personal or family history of an abnormal heart rhythm seen as a 'prolonged QT interval' on a heart monitoring trace or ECG.
- People taking other medicines that can increase the risk of a 'prolonged QT interval' (see end of factsheet for examples).
- People with a history of stroke or mini-stroke (TIA).
- Elderly people with dementia and a risk of stroke (other similar antipsychotic medicines are associated with an increased risk of stroke and death in this group of people).
- People with a personal or family history of blood clots (venous thromboembolism), for example in a vein of the leg (deep vein thrombosis) or in the lungs (pulmonary embolism).
- People with other risk factors for getting a blood clot, for example smoking, being overweight, taking the contraceptive pill, being over 40, recent major surgery or being immobile for prolonged periods.
- People with low blood pressure (hypotension).
- People who are dehydrated.
- People with a history of seizures, eg epilepsy.
- People with conditions that increase the risk of epilepsy or convulsions, eg brain damage or withdrawal from alcohol.
- Parkinson's disease.
- People with a history of a drop in the numbers of white blood cells in the blood, particularly if this was caused by a medicine.
- People with a tumour of the pituitary gland in the brain that produces the hormone prolactin (prolactinoma).
- People with tumours whose growth may be stimulated by the hormone prolactin, eg breast cancer.
- Diseases associated with chronic severe diarrhoea (as this could cause the Invega tablet to pass through the gut too quickly, making it less effective).
Not to be used in
- People who are allergic to risperidone.
- This medicine is not recommended for people who have any severe narrowing or blockage in their gut, or for people who have difficulty swallowing.
- This medicine is not recommended for people with severely decreased kidney function.
- This medicine is not recommended for children less than 18 years of age, as its safety and efficacy have not been established in this age group.
- Invega 3mg tablets contain lactose and should not be taken by people with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption. Other strengths of Invega do not contain lactose.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine during pregnancy has not been established. It should not be used in pregnancy, particularly in the first and third trimesters, unless considered essential by your doctor. If the medicine is used during the third trimester it could cause side effects or withdrawal symptoms in the baby after birth and the baby may need extra monitoring because of this. Seek further medical advice from your doctor.
- If you do get pregnant while taking this medicine it is important to consult your doctor straight away for advice. You should not suddenly stop taking this medicine unless your doctor tells you to, as this could cause your symptoms to come back.
- This medicine passes into breast milk and could be harmful to a nursing infant. It should not be used during breastfeeding. Mothers who need to take this medicine should not breastfeed and should bottlefeed instead. Seek further medical advice from your doctor.
- This medication should be swallowed whole, do not chew or crush.
- This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
Very common (affect more than 1 in 10 people)
- Sleepiness or sedation.
- Difficulty sleeping (insomnia).
- Abnormal movements of the hands, legs, face, neck and tongue, eg tremor, twitching, rigidity (extrapyramidal effects).
- Increased salivation.
- Anxiety, restlessness and agitation (akathisia).
Common (affect between 1 in 10 and 1 in 100 people)
- Sore throat.
- Blocked nose.
- Infection of the breathing passages, eg sinusitis, flu, bronchitis.
- Dry mouth.
- Disturbances of the gut such as nausea, vomiting, constipation, diarrhoea, indigestion or abdominal pain.
- Changes in appetite or weight (see warning section above).
- Faster or slower than normal heart beat.
- Abnormal heart rhythm seen as a 'prolonged QT interval' on a heart monitoring trace or ECG.
- Drop in blood pressure causing dizziness that occurs when moving from a lying down or sitting position to sitting or standing - see warning section above.
- High blood pressure.
- Pain in the muscles, joints or back.
- Rash or itching.
- Feeling weak or tired.
- Stopping of menstrual periods in women.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Increased blood glucose levels or diabetes. Tell your doctor if you notice you feel unusually hungry or thirsty, or need to pass urine more often than usual. People with diabetes should monitor their blood sugar closely.
- Elevated levels of fats called triglycerides in the blood.
- Sexual problems such as reduced sex drive, erectile dysfunction or inability to orgasm.
- Pins and needles or numb sensations.
- Dry eyes, conjunctivitis.
- Ear pain, sensation of ringing or other noise in the ears (tinnitus).
- Irregular heartbeat (arrhythmia) or awareness of your heartbeat (palpitations).
- Shortness of breath.
- Hair loss.
- Pain or difficulty passing urine.
- Urinary incontinence.
- Excessive fluid retention in the body tissues, resulting in swelling (oedema).
Rare (affect between 1 in 1000 and 1 in 10,000 people)
- Decreased numbers of blood cells in the blood (see warning section above).
- Prolonged erection (priapism). If you get an erection that lasts longer than four hours while taking this medicine, you should consult a doctor immediately. Treatment of this condition should not be delayed more than six hours, as this can cause damage to the erectile tissue in the penis and irreversible erectile dysfunction.
- Neuroleptic malignant syndrome (see warning section above).
- Tardive dyskinesia (see warning section above).
- Problem with eye movement such as rolling of the eyes.
- Red or watery eyes.
- Blood clot in the leg or the lungs (thromboembolism) – see warning section above.
- Irregular heart beat called atrial fibrillation.
- Yellowing of the skin and whites of the eyes (jaundice).
- Inflammation of the pancreas (pancreatitis).
- Breast enlargement or discharge.
- Skin reactions such as dry or scaly skin, eczema, skin discoloration.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
Paliperidone is a metabolite of risperidone and so may potentially cause some of the side effects reported with risperidone.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
There may be an increased risk of drowsiness and sedation if paliperidone is taken with any of the following (which can also cause drowsiness):
- barbiturates, eg amobarbital, phenobarbital
- benzodiazepines, eg diazepam, temazepam
- MAOI antidepressants, eg phenelzine
- sedating antihistamines, eg chlorphenamine, hydroxyzine
- sleeping tablets, eg zopiclone
- strong opioid painkillers, eg morphine, codeine
- tricyclic antidepressants, eg amitriptyline.
Paliperidone may enhance the blood pressure-lowering effects of medicines that lower blood pressure, including medicines used to treat high blood pressure (antihypertensives) and medicines that lower blood pressure as a side effect, eg benzodiazepines. If you are taking medicines that lower blood pressure you should tell your doctor if you feel dizzy or faint after starting treatment with this medicine, as your doses may need adjusting.
There may be an increased risk of abnormal heart rhythms (prolonged QT interval on a heart monitoring trace or ECG) if this medicine is taken in combination with any of the following medicines:
- antiarrhythmics (medicines to treat abnormal heart beats), eg amiodarone, procainamide, disopyramide, sotalol
- the antihistamines astemizole, mizolastine or terfenadine
- arsenic trioxide
- certain antidepressants, eg amitriptyline, imipramine, maprotiline
- certain antimalarials, eg halofantrine, chloroquine, quinine, mefloquine, Riamet
- certain other antipsychotics, eg thioridazine, haloperidol, sertindole, pimozide
- intravenous erythromycin or pentamidine
There may also be an increased risk of a prolonged QT interval if medicines that can alter the levels of salts such as potassium or magnesium in the blood, eg diuretics such as furosemide, are taken in combination with paliperidone.
Paliperidone may oppose the effect of medicines for Parkinson's disease that work by stimulating dopamine receptors in the brain, for example levodopa, ropinirole, pergolide, bromocriptine.
Paliperidone may oppose the effect of anticonvulsant medicines used to treat epilepsy.
Paliperidone may increase blood sugar levels and disturb the control of diabetes. People with diabetes may need an adjustment in the dose of their antidiabetic medication.
Paliperidone may oppose the effect of histamine (used to treat leukaemia) and is not recommended for people having this treatment.
Medicines that may speed up the passage of Invega tablets through the gut, for example metoclopramide, could affect the absorption of paliperidone into the bloodstream.
The following medicines may speed up the breakdown of paliperidone in the body and so could make it less effective. If you take any of these medicines your doctor may need to increase your dose of paliperidone:
- the herbal remedy St John's wort (Hypericum perforatum).
This medicine should not be used in combination with risperidone.
Other medicines containing the same active ingredient