What is risperidone injection used for? A Comprehensive Guide

October 11, 2025 •

5 min read

Risperidone injection is a long-acting injectable (LAI) form of an atypical antipsychotic, primarily used for the treatment of schizophrenia and bipolar I disorder in adults. It is a crucial tool for reducing the risk of relapse, particularly for patients who face challenges with consistent daily oral medication adherence.

Quick Summary

This article explains the approved uses of risperidone injection for schizophrenia and bipolar disorder. It covers its mechanism, benefits over oral medication, administration process, potential side effects, and important safety considerations for patients.

Key Points

Approved Indications: Risperidone injection is FDA-approved for the treatment of schizophrenia and maintenance therapy for bipolar I disorder in adults.
Improved Adherence: The long-acting injectable (LAI) form helps overcome the challenge of medication non-adherence, a common issue with chronic psychiatric conditions.
Reduced Relapse and Hospitalization: Studies show that the injection is more effective than the oral form in preventing relapses and subsequent hospitalizations.
Mechanism of Action: It works by balancing dopamine and serotonin levels in the brain to improve mood, thinking, and behavior.
Regular Administration: Depending on the brand, injections are given by a healthcare professional every two weeks, once a month, or every two months.
Significant Side Effects: Patients should be aware of potential side effects, including serious risks like tardive dyskinesia, NMS, and metabolic changes, and a boxed warning for elderly patients with dementia.
Requires Oral Overlap: Some long-acting formulations need a period of oral supplementation at the beginning of treatment to ensure therapeutic levels are reached.

Risperidone injection is a long-acting formulation of the atypical antipsychotic medication, risperidone. Unlike daily oral tablets, the injectable form is administered by a healthcare professional at regular intervals, such as every two weeks, once a month, or every two months, depending on the specific brand. This delivery method is designed to provide a steady and consistent level of medication over an extended period, which can significantly benefit patients with chronic psychiatric conditions.

The Primary Indications for Risperidone Injection

Risperidone injection is an FDA-approved treatment for several serious mental health conditions in adults. The primary indications include:

Treating Schizophrenia

Risperidone injection is indicated for the treatment of schizophrenia, a chronic and severe mental disorder that affects how a person thinks, feels, and behaves. It helps manage both the acute symptoms and provides long-term maintenance therapy to prevent relapse.

Positive symptoms: These include hallucinations, delusions, and disorganized thinking.
Negative symptoms: These involve a reduced ability to initiate or sustain planned activities, as well as a decrease in expression of emotion.
Relapse prevention: Long-term injectable risperidone has been shown to be superior to oral forms in preventing relapse and reducing the need for hospitalization in patients with schizophrenia, largely due to improved medication adherence.

Managing Bipolar I Disorder

Risperidone injection is also approved for the maintenance treatment of Bipolar I Disorder in adults, either as a standalone therapy or in combination with mood stabilizers like lithium or valproate. This application helps prevent future manic or mixed episodes and stabilize mood over time.

How Risperidone Injection Works

As an atypical antipsychotic, risperidone works by balancing the levels of natural substances in the brain, including dopamine and serotonin. By blocking certain dopamine and serotonin receptors, risperidone helps restore the proper balance of these neurotransmitters, leading to improvements in thinking, mood, and behavior. The long-acting injectable formulations, such as Risperdal Consta®, Perseris®, and Uzedy®, release the medication gradually into the bloodstream over time. This sustained release smooths out the peaks and troughs in drug concentration, potentially reducing some side effects associated with dose fluctuations and providing a consistent therapeutic effect.

Advantages of Injectable Risperidone over Oral Medication

For patients with chronic psychiatric illnesses, adherence to daily medication can be a significant challenge. Injectable risperidone offers several notable benefits over the oral form:

Improved Adherence: The scheduled injection means patients and healthcare providers can ensure consistent medication administration, circumventing the issue of missed daily doses.
Relapse Prevention: Clinical studies have demonstrated that long-acting injectable risperidone leads to better relapse prevention and fewer hospitalizations compared to oral risperidone, particularly in patients with a history of poor adherence.
Steady Drug Levels: The sustained release of the drug helps maintain stable plasma concentrations, avoiding the fluctuations experienced with daily oral dosing.
Enhanced Efficacy: For some patients, the improved adherence and stable drug levels translate into better overall symptomatic control and functioning.
Objective Monitoring: The injectable format allows healthcare providers to confirm medication compliance, providing a more reliable basis for treatment planning.

Administration and Dosage

The method and frequency of risperidone injection depend on the specific formulation being used.

Brands and Delivery:
- Risperdal Consta®: Administered intramuscularly (IM) every two weeks.
- Perseris® and Uzedy®: Administered subcutaneously (SubQ) once a month or every two months for Uzedy®.
Oral Overlap: Many long-acting risperidone injections require a period of oral risperidone supplementation during the initial weeks of treatment. This is because the extended-release formula takes time to build up to a therapeutic level.
Dose Adjustment: Healthcare professionals monitor a patient's response and tolerability to adjust the dose over time.

Potential Side Effects and Safety Information

Like all medications, risperidone injection carries potential side effects, some of which can be serious. Awareness and monitoring are crucial for safe use.

Common Side Effects

Movement-related: Tremors, muscle stiffness, restlessness, and involuntary movements (akathisia).
General: Dizziness, drowsiness, sedation, weight gain, increased appetite, and injection site reactions (pain, redness, swelling).
Hormonal: Increased levels of the hormone prolactin, which can lead to breast enlargement, missed periods, or sexual dysfunction.

Serious Side Effects and Warnings

Boxed Warning: A boxed warning alerts healthcare providers and patients that elderly patients with dementia-related psychosis who use risperidone or other antipsychotics have an increased risk of death. The medication is not approved for this condition.
Tardive Dyskinesia (TD): This is a condition characterized by involuntary movements, particularly of the face and tongue. It can develop with long-term use and may be irreversible in some cases.
Neuroleptic Malignant Syndrome (NMS): A rare but potentially fatal reaction, NMS involves symptoms such as high fever, severe muscle rigidity, altered mental status, and autonomic instability.
Metabolic Changes: Antipsychotics, including risperidone, can increase the risk of high blood sugar (diabetes) and high cholesterol. Regular monitoring is essential.
Orthostatic Hypotension: A sudden drop in blood pressure when standing can cause dizziness or fainting. Patients should rise slowly to avoid falls.

Precautions and Monitoring

Before starting risperidone injection, a thorough medical evaluation is necessary. Healthcare providers will monitor for conditions like:

Kidney or liver disease
Diabetes
Cardiovascular conditions
Seizures

Risperidone Injection vs Oral Risperidone: A Comparison


Feature	Risperidone Injection	Oral Risperidone
Administration	By healthcare professional via intramuscular (IM) or subcutaneous (SubQ) injection.	Self-administered as tablets or solution.
Frequency	Ranges from every two weeks to every two months, depending on the brand.	Daily or twice daily dosing.
Adherence	High adherence rate, as injections are professionally administered.	Dependent on patient compliance, often a challenge in chronic conditions.
Drug Levels	Provides steady, consistent plasma drug levels over time, reducing fluctuations.	Experience peaks and troughs in plasma drug levels with each dose.
Relapse Risk	Significantly lower risk of relapse and hospitalization compared to oral form.	Higher risk of relapse, especially in partially adherent patients.
Initiation	Requires oral overlap during the first few weeks to reach therapeutic levels.	Immediate therapeutic effect (onset of action is faster).

What to Discuss with Your Doctor

It is vital to have an open conversation with your healthcare provider about your treatment and medical history before starting risperidone injection. Key discussion points include:

Allergies: Inform your doctor of any allergies to risperidone, paliperidone, or other medications.
Current Medications: Provide a complete list of all prescription and nonprescription drugs, supplements, and herbal products you are taking to prevent harmful drug interactions.
Medical History: Disclose any past or present medical conditions, especially heart, kidney, or liver disease, seizures, or diabetes.
Pregnancy and Breastfeeding: Discuss if you are pregnant, planning to become pregnant, or breastfeeding.
Side Effects: Talk about any side effects you experience, no matter how minor they seem.

Conclusion

Risperidone injection is a valuable and effective treatment option for adults with schizophrenia and bipolar I disorder. The long-acting injectable format addresses the critical issue of medication non-adherence by providing a consistent and reliable drug delivery system. This can lead to better symptom control, reduced relapse rates, and fewer hospitalizations. However, patients and healthcare providers must work closely to monitor for potential side effects and ensure the safety and efficacy of the treatment. For individuals who struggle with daily oral medication, risperidone injection offers a significant step toward achieving long-term stability and improving overall quality of life. The decision to use this form of risperidone should be made after careful consideration and discussion with a healthcare provider, weighing the benefits of improved adherence against the potential for side effects. For detailed information, consult authoritative sources such as MedlinePlus.

Frequently Asked Questions

The main difference lies in how the medication is administered and its duration of action. Oral risperidone is taken daily, while the injectable form (LAI) is given by a healthcare professional at regular, less frequent intervals (e.g., every 2 weeks to every 2 months). The injection provides more consistent drug levels, which helps improve medication adherence and reduce relapse risk.

Studies have shown that for patients with a history of poor medication adherence, the injectable form is more effective in preventing relapse and hospitalization compared to the oral form, primarily due to ensured compliance. For patients who are reliably adherent to their oral medication, the efficacy may be comparable.

The frequency depends on the brand. For example, Risperdal Consta® is typically given every two weeks, while Perseris® is given once a month. Uzedy® offers dosing options of once a month or once every two months.

Yes, risperidone injection carries a boxed warning. It warns that older adults with dementia-related psychosis who are treated with antipsychotic drugs like risperidone have an increased risk of death. It is not approved for this use.

Serious side effects include Neuroleptic Malignant Syndrome (NMS), tardive dyskinesia (involuntary movements), metabolic changes (like high blood sugar and weight gain), and an increased risk of stroke in elderly dementia patients.

Yes, for many long-acting risperidone injections, oral risperidone (or another antipsychotic) is given during the initial weeks of treatment. This is to ensure adequate therapeutic levels are present while the extended-release formula reaches its full effect.

No, you should not stop treatment without consulting your doctor. Discontinuing medication, especially for chronic conditions like schizophrenia or bipolar disorder, can lead to a relapse of symptoms. Your doctor will determine the appropriate duration of therapy.

For bipolar I disorder, risperidone injection is used as a maintenance treatment to prevent the recurrence of manic or mixed episodes. It can be used alone (monotherapy) or as an add-on to other mood stabilizers.