Invega

Schizophrenia

Invega is used to treat schizophrenia in adults and adolescents between the ages of 12 and 17. It helps manage symptoms associated with the condition, such as:

• Hallucinations (hearing or seeing things that are not there)
• Delusions (strong beliefs in things that are not true)
• Difficulty thinking clearly
• Problems with social interaction or emotional expression

Schizoaffective Disorder

Invega is also used to treat schizoaffective disorder in adults. This condition is characterized by a combination of schizophrenia symptoms and mood disorder symptoms, such as mania or depression. For this condition, the medication may be used in two ways:

• Monotherapy: Used alone to manage symptoms.
• Adjunctive therapy: Used in combination with other medications, such as mood stabilizers or antidepressants.

Available Forms

This medication is available in several formulations, which are prescribed based on the patient's needs and treatment history:

• Extended-release tablets: These are taken daily by mouth.
• Long-acting injections: These are administered by a healthcare professional into the muscle. Depending on the specific product, these injections may be given once a month, every three months, or every six months to provide continuous symptom control.

Mechanism of Action

Invega, which contains the active ingredient paliperidone, works by altering the activity of certain natural substances in the brain called neurotransmitters. These chemicals are responsible for sending signals between nerve cells and play a significant role in mood, behavior, and thought processes.

The medication primarily targets two specific neurotransmitters:

• Dopamine: It helps regulate the overactivity of dopamine, which is often linked to symptoms like hallucinations and delusions.
• Serotonin: It also affects serotonin levels, which can help improve mood, cognitive function, and social interaction.

While the exact way Invega works is not fully understood, researchers believe it functions by blocking specific receptors for these chemicals on the surface of brain cells. By modulating these pathways, the medication helps to decrease abnormal excitement in the brain and restore a more stable chemical balance.

Common Side Effects

Many people using Invega experience mild side effects. These may include:

• Drowsiness or fatigue
• Dizziness or lightheadedness
• Headache
• Dry mouth
• Weight gain
• Stomach pain, nausea, or constipation
• Restlessness or an inability to sit still
• Muscle stiffness or tremors
• Pain, redness, or swelling at the injection site

Serious Side Effects

Contact a healthcare provider immediately if you experience any of the following serious symptoms:

• Uncontrolled movements of the face, tongue, or other body parts (tardive dyskinesia)
• High fever, stiff muscles, confusion, and sweating (neuroleptic malignant syndrome)
• High blood sugar symptoms, such as increased thirst or frequent urination
• Seizures
• Difficulty swallowing
• Irregular or fast heartbeat
• Fainting or severe dizziness
• Vision changes
• Signs of infection, such as fever or sore throat
• A prolonged or painful erection lasting four hours or more
• Severe allergic reactions, including rash, itching, or swelling of the face and throat

Boxed Warning: Dementia-Related Psychosis

Elderly patients with dementia-related psychosis who are treated with antipsychotic medications like Invega face an increased risk of death. Invega is not approved for the treatment of dementia-related psychosis.

Serious Neurological Reactions

• Neuroleptic Malignant Syndrome (NMS): This is a rare but life-threatening condition. Symptoms include high fever, stiff muscles, confusion, and irregular pulse or blood pressure.
• Tardive Dyskinesia: This medication may cause involuntary movements, especially of the face, tongue, or jaw. These movements may become permanent even after the medication is stopped.

Metabolic and Physical Effects

• Blood Sugar and Diabetes: Invega can cause high blood sugar (hyperglycemia), which may lead to or worsen diabetes. Monitoring for symptoms such as increased thirst or frequent urination is common.
• Weight Gain: Significant increases in body weight have been reported in patients taking this medication.
• Cholesterol Changes: Treatment may lead to undesirable changes in cholesterol and triglyceride levels.
• Prolactin Levels: Invega can increase prolactin levels in the blood, which may cause breast swelling, milk production, or changes in menstrual cycles.

Heart and Blood Pressure

Invega may cause a heart rhythm issue called QT prolongation. It can also cause a sudden drop in blood pressure when standing up (orthostatic hypotension), leading to dizziness or fainting.

General Precautions

• Seizures: The medication may lower the seizure threshold, increasing the risk of seizures in some individuals.
• Cognitive and Motor Impairment: Drowsiness and impaired judgment may occur. Caution is advised when driving or operating machinery.
• Temperature Regulation: Invega can interfere with the body's ability to reduce its temperature. Caution is needed during heavy exercise or exposure to extreme heat.
• Priapism: In rare cases, this medication can cause a painful, prolonged erection that requires immediate medical care to prevent permanent damage.

Pregnancy

The safety of using Invega during pregnancy has not been fully established. Research indicates that newborns exposed to antipsychotic medications like Invega during the third trimester may experience symptoms after birth, including:

• Muscle stiffness or weakness
• Tremors
• Sleepiness
• Breathing problems
• Difficulty feeding

If you become pregnant while taking Invega, do not stop the medication without consulting your doctor. Stopping treatment abruptly can cause a relapse of symptoms. There is a pregnancy registry available to monitor the health of individuals and their babies who are exposed to antipsychotics during pregnancy.

Breastfeeding

Invega can pass into breast milk and may be absorbed by a nursing infant. Because the effects on the baby are not fully understood, it is important to talk with a healthcare professional about the risks and benefits of breastfeeding while using this medication. They can help determine the safest course of action for both the parent and the child.

Available Forms

Invega is provided in two primary forms: oral tablets and long-acting injections.

Extended-Release Tablets

The oral form of this medication is an extended-release tablet. It is designed to be taken once daily. These tablets use a special delivery system that releases the medicine at a controlled rate throughout the day. It is important to swallow the tablet whole with liquid and not to crush, chew, or divide it.

Injectable Suspensions

Paliperidone is also available as an extended-release injectable suspension. These injections are administered by a healthcare provider into the muscle of the arm or buttocks. There are several versions of the injection that differ by how often they are administered:

• Once-monthly injections
• Injections administered every three months
• Injections administered every six months

A healthcare provider determines the appropriate form and schedule based on the patient's treatment needs and how they have responded to previous doses of the medication.

FDA Approval and Indications

Invega (paliperidone) is approved by the U.S. Food and Drug Administration (FDA) for the treatment of schizophrenia in adults and adolescents aged 12 to 17 years. It is also approved for the treatment of schizoaffective disorder in adults, where it may be used alone or in combination with mood stabilizers or antidepressants.

Boxed Warning

The FDA has issued a boxed warning for Invega because elderly patients with dementia-related psychosis who are treated with antipsychotic medications are at an increased risk of death. Invega is not FDA-approved for the treatment of patients with dementia-related psychosis.

Regulatory Status and Formulations

Invega is a prescription medication and is available in several FDA-approved formulations designed for different dosing schedules:

• Oral Tablets: Extended-release tablets taken once daily.
• Intramuscular Injections: Long-acting injectable versions administered by healthcare professionals. These include formulations administered once monthly, every three months, or every six months.

The injectable forms are primarily indicated for the treatment of schizophrenia in adults and, depending on the specific product, for the treatment of schizoaffective disorder in adults.

Managing Discontinuation

It is important not to stop taking Invega (paliperidone) without first consulting your doctor. Stopping the medication suddenly may cause the symptoms of schizophrenia or schizoaffective disorder to return. Your healthcare provider will typically recommend a gradual reduction in dosage to help prevent a relapse.

Long-Acting Injectables

Invega is available in several long-acting injectable forms, such as Invega Sustenna, Invega Trinza, and Invega Hafyera. Because these medications are designed to release slowly over weeks or months, the drug remains in your system for a significant amount of time after the last injection. If you stop treatment, any withdrawal effects or the return of original symptoms may not appear immediately.

Withdrawal in Newborns

If Invega is taken during the last three months of pregnancy, the baby may experience withdrawal symptoms after birth. These symptoms can include:

• Agitation or irritability
• Feeding problems
• Muscle stiffness or limpness
• Sleepiness
• Breathing difficulties
• Tremors

If you are pregnant or planning to become pregnant, discuss the risks and benefits of continuing Invega with your doctor to manage potential risks to the newborn.