Risperdal: 6 things you should know
Medically reviewed by C. Fookes, BPharm Last updated on Jan 28, 2019.
1. How it works
- Risperdal is a brand (trade) name for the drug risperidone. Risperidone is used to treat psychotic symptoms. Experts are not sure exactly how risperidone works but suggest that its main effects are the result of it blocking both dopamine and serotonin receptors. Other effects may be due to blocking other neurotransmitter receptors.
- Risperdal belongs to the class of medicines called atypical antipsychotics. Atypical means it is less likely than older antipsychotics to cause side effects.
- Relieves psychotic symptoms such as hallucinations, delusions, confusion, disturbed thoughts, and lack of insight or self-awareness.
- Used either alone or in combination with other medicines for the treatment of schizophrenia, acute mania or mixed episodes in bipolar disorder.
- Risperdal in small dosages may be also used to relieve irritability and symptoms of aggression, temper tantrums, and mood fluctuations in children with autistic disorder.
- People are more likely to adhere to treatment with Risperdal than to treatment with older antipsychotics.
- Risperdal is available as a generic under the name risperidone.
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- Drowsiness that may affect your ability to drive or operate machinery. Avoid alcohol.
- Extrapyramidal symptoms (such as restlessness, tremor, uncontrolled muscle contractions) are more likely at dosages greater than 6mg/day. Higher dosages have also not been associated with extra efficacy. Dosages for adolescents should be limited to 3mg/day to limit the risk of side effects.
- Other common side effects include anxiety, blurred vision, dizziness, gastrointestinal disturbances (nausea, vomiting, constipation, diarrhea, dyspepsia, pain), excessive salivation, tiredness, weight gain, and rash. Uncommonly, a reduction in the numbers of white blood cells, swallowing difficulty, priapism (sustained erections) and seizures may occur.
- A drop in blood pressure on standing, particularly during the initial dose titration period; dosage may need to be reduced then titrated up slowly. May not be suitable for people with known cardiovascular disease (history of a heart attack, angina, heart failure, or arrhythmia), stroke and people at risk of dehydration.
- An increase in blood sugar levels. People with a history of diabetes or at risk of diabetes should be monitored closely. May also cause undesirable changes in blood cholesterol and lipid levels and weight gain (on average, 4.3kg after 6 months of therapy).
- An increase in prolactin levels (risk is higher than with most other antipsychotics), leading to side effects such as impaired fertility, an absence of menstruation, unwanted lactation, breast enlargement in men, impotence, and decreased bone density. May not be suitable for people with a history of prolactin-dependent breast cancer.
- Potentially irreversible tardive dyskinesia, even with low dosages used short-term. Symptoms include facial grimacing, repetitive chewing, and tongue thrusting.
- May interact with some medicines. Dosage may need increasing when used with enzyme inducers such as carbamazepine or phenytoin; dosage may need reducing when used with enzyme inhibitors such as fluoxetine or paroxetine. See prescribing information for Risperdal for the full list of interactions.
- Should not be used for the treatment of dementia-related psychosis in elderly people as it has been associated with a higher risk of death.
- Rarely, may cause Neuroleptic Malignant Syndrome (NMS); symptoms include high body temperature, muscle rigidity, and mental disturbances; discontinue immediately and seek urgent medical advice.
Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.
- Risperdal should be started at a lower dose initially then gradually titrated up depending on an individual's response and tolerability. Follow your doctor's instructions.
- Some people are more sensitive to the effects of Risperdal and may need a more gradual increase in dosage - talk with your doctor if you are having trouble tolerating any side effects of Risperdal.
- Ask your doctor about splitting your daily dose of Risperdal into a morning and evening dose if you find Risperdal makes you too sleepy during the day. Do not drive or perform hazardous tasks if Risperdal makes you sleepy.
- Avoid alcohol as it may potentiate the sedative effect of Risperdal.
- Risperdal may be used long-term; however, a doctor should periodically reevaluate effectiveness and monitor for the presence of side effects. When used to delay relapse in people with schizophrenia, effectiveness in trials has lasted for at least 2 years (the duration of the trial).
- Risperdal may make you feel dizzy when going from a sitting or lying down position to standing. This may increase your risk of falls. Stand up slowly and remove any fall hazards from your home (such as loose rugs).
- Talk with your doctor if you develop any worrying side effects such as uncontrollable facial grimacing, restlessness, severe dizziness, or severe abdominal discomfort.
- Tell your doctor if you are intending to become pregnant and you are taking Risperdal as your doctor may wish to change you to a different medication. Risperdal is incompatible with breastfeeding.
6. Response and Effectiveness
- Some effects may be noticed within a few days but it may take up to three to four weeks for the full effects of Risperdal to be seen.
- Risperdal is metabolized to an active metabolite, 9-hydroxy-risperidone.
- Risperdal orally disintegrating tablets, Risperdal oral solution, and Risperdal tablets are all bioequivalent (this means that there is no difference in the extent to which they are absorbed and their effect at the same dosage).
Risperdal (risperidone) [Package Insert]. Revised 09/2018. Janssen Pharmaceuticals, Inc https://www.drugs.com/pro/risperdal.html
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Risperdal only for the indication prescribed.
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Other brands: Perseris