Risperidone (Risperdal): Uses, Forms, Warnings

What is risperidone?

Risperidone is an active ingredient used in medicines for certain psychiatric and behavioral conditions. It is available in different formulations, including oral tablets, orally disintegrating tablets, oral solution, and some injectable forms.

In the United States, brand names include Risperdal, Risperdal Consta, Perseris, and Risperdal M-Tab.

How risperidone works

Risperidone is described as a selective monoaminergic antagonist with high affinity for serotonergic 5-HT2 and dopaminergic D2 receptors.

In practical terms, this means it acts on certain brain receptors involved in mood, behavior, and thought processes.

What risperidone is used for

According to the source content, risperidone may be used for the following indications depending on the formulation:

• Schizophrenia.
• Moderate to severe manic episodes associated with bipolar disorder.
• Short-term treatment of persistent aggression in patients with moderate to severe Alzheimer-type dementia who do not respond to other non-pharmacological measures and when there is a risk of harm to themselves or others.
• Short-term treatment of persistent aggression in behavioral disorders in children aged 5 years and older and adolescents with below-average intellectual functioning or mental retardation diagnosed according to DSM-IV criteria, when the severity of aggression or other disruptive behaviors requires pharmacological treatment.
• Maintenance of schizophrenia in patients stabilized with oral antipsychotics, for certain injectable formulations.

Available forms and administration

Oral forms

Buccodispersible tablets: place on the tongue; they begin to disintegrate in seconds. Water may be used if desired.

Oral solution: take with a non-alcoholic beverage, except tea.

Injectable form

Some injectable formulations are used for maintenance treatment in adults who are already stabilized on oral antipsychotics.

Posology overview

The following information is a summary of the source content and is not a substitute for the official prescribing information.

Note: The source also states that oral initial and consecutive doses should be reduced by half in renal or hepatic insufficiency.

Contraindications

The source lists hypersensitivity to risperidone as a contraindication.

Warnings and precautions

Risperidone requires extra caution in several situations. The source highlights the following:

• Cardiovascular disease, bradycardia, electrolyte disorders, and family history of prolonged QT interval.
• History of seizures.
• Elderly patients, renal insufficiency, and hepatic insufficiency.
• Patients with risk of stroke, pre-existing hyperprolactinemia, or prolactin-dependent tumors.
• Situations that may raise body temperature and risk factors for venous thromboembolism.
• Possible masking of symptoms of overdose or other conditions because of its antiemetic effect.
• Parkinson’s disease or dementia with Lewy bodies, where risk and benefit should be assessed carefully.
• Monitoring for hyperglycemia, weight changes, orthostatic hypotension, leukopenia, neutropenia, and agranulocytosis.
• Risk of neuroleptic malignant syndrome, tardive dyskinesia, or stroke, where treatment should be stopped if these signs appear.
• In elderly patients with dementia, the source notes increased mortality in some settings, including use alone or with furosemide.
• In children, the source advises evaluating physical and social causes of aggressive behavior before treatment.
• Risk of intraoperative floppy iris syndrome during and after cataract surgery.
• Rare anaphylactic reactions have been reported with injectable use, even in patients who previously tolerated oral risperidone.

Kidney and liver impairment

The source advises caution in both renal and hepatic insufficiency. For oral use, it states that initial and consecutive doses should be reduced by half.

If kidney or liver function is reduced, the official prescribing information should be checked before use.

Drug interactions

Risperidone may interact with other medicines and substances. The source lists the following examples:

• Increased sedation with alcohol, opiates, antihistamines, and benzodiazepines.
• Decreased plasma concentration with carbamazepine, phenytoin, rifampicin, and phenobarbital.
• Increased plasma concentration with fluoxetine, paroxetine, verapamil, phenothiazines, tricyclic antidepressants, some beta-blockers, and itraconazole.
• Possible antagonism of levodopa and other dopamine agonists.
• Hypotension risk with antihypertensive medicines.
• Not recommended with paliperidone.

Pregnancy and breastfeeding

The source says risperidone was not teratogenic in animal studies, but other reproductive toxicity was observed. The possible risk to humans is unknown, so it should not be used unless clearly necessary.

Risperidone and its metabolite are excreted in small amounts in human milk. The source notes that adverse effects in infants are not well documented, so the benefits of breastfeeding should be weighed against possible risks.

Driving and operating machinery

Risperidone can cause drowsiness, dizziness, visual disturbances, and reduced reaction ability. Because of this, caution is advised when driving or using dangerous machinery, especially until individual sensitivity is known.

Possible adverse reactions

The source lists a broad range of possible adverse reactions, including:

• Upper respiratory tract infection, pneumonia, bronchitis, sinusitis, urinary tract infection, and flu-like illness.
• Hyperprolactinemia, changes in appetite, weight gain or weight loss, and hyperglycemia.
• Insomnia, depression, anxiety, agitation, and sleep disorders.
• Parkinsonism, headache, sedation, akathisia, dystonia, dizziness, dyskinesia, and tremor.
• Blurred vision, tachycardia, hypotension, and hypertension.
• Respiratory symptoms such as dyspnea, pharyngeal pain, cough, and nasal congestion.
• Digestive symptoms such as abdominal pain, nausea, vomiting, constipation, diarrhea, dyspepsia, and dry mouth.
• Rash, muscle spasms, musculoskeletal pain, back pain, arthralgia, urinary incontinence, erectile dysfunction, amenorrhea, and galactorrhea.
• Edema, fever, chest pain, asthenia, fatigue, pain, increased liver enzymes, and falls.
• With intramuscular use: anemia, injection-site pain, and injection-site reactions.

This is not a complete list. The official leaflet should be checked for the full safety profile.

What to verify with a doctor or pharmacist

If you are reviewing risperidone for yourself or someone else, it is useful to confirm:

• Which formulation is being used: oral tablet, orally disintegrating tablet, solution, or injectable.
• The exact indication for treatment.
• Whether kidney or liver function changes the usual approach.
• Whether any other medicines may interact.
• Which warning signs should prompt urgent medical review.

FAQ

Sources and references

• FDA Medication Guides
• UNII: L6UH7ZF8HC
• ChemIDplus
• DrugPortal
• PubChem CID: 5073
• NCI Thesaurus: C29416