Invega dosage, forms, and strengths

Invega is a brand-name prescription antipsychotic FDA-approved to treat schizophrenia and schizoaffective disorder. Invega comes in four different versions: an extended-release tablet called Invega and three types of injections: Invega Sustenna, Invega Trinza, and Invega Hafyera. Invega oral tablets are taken once daily. Injections are administered once monthly, every three months, or every six months, depending on the product used. Tolerability is always an issue with antipsychotic medications, so some people may quit Invega because of common side effects like dry mouth, increased blood pressure, involuntary body movements, restlessness, weight gain, racing heartbeats (tachycardia), or body temperature irregularities.

Invega forms and strengths

Invega oral tablets are extended-release formulations that are taken once daily. People who are established on Invega tablets can transition to longer-lasting Invega injections:

• Extended-release oral tablet: 1.5 mg, 3 mg, 6 mg, 9 mg

• Intramuscular injection (Invega Sustenna—once-monthly doses): 39 mg/0.25 mL, 78 mg/0.5 mL, 117 mg/0.75 mL, 156 mg/mL, 234 mg/1.5 mL

• Intramuscular injection (Invega Trinza—once every three months doses): 273 mg/0.88 mL, 410 mg/1.32 mL, 546 mg/1.75 mL, 819 mg/2.63 mL

• Intramuscular injection (Invega Hafyera—twice yearly doses): 1,092 mg/3.5 mL, 1,560 mg/5 mL

Invega dosage for adults

Invega extended-release tablets and injections are FDA-approved to treat schizophrenia and schizoaffective disorder. For schizoaffective disorder, Invega can be used alone or with other mood-stabilizing drugs or antidepressants.

Invega is suitable for anyone with these disorders, but it is containdicated in people who are allergic to its active ingredient, paliperidone, or to a similar drug called risperidone. Though not an absolute contraindication, the FDA has mandated a boxed warning that Invega is not approved for elderly patients with dementia-related psychosis because of an increased risk of death.

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Invega dosage for schizophrenia

Schizophrenia is a disabling mental health condition primarily characterized by psychosis: false beliefs about the world (delusions), hallucinations, incoherent or disorganized speech, and erratic or disorganized behavior. Schizophrenia affects 1 out of 100 people and involves both physical and chemical changes to the brain. The standard treatment of schizophrenia involves antipsychotic medications and various types of therapy.

Antipsychotic medications change the chemistry of the brain to make nerves in the brain less excitable and uncontrolled. Paliperidone, the active ingredient in Invega, is closely related to Risperdal (risperidone). Both work by slowing down the brain.

Antipsychotics, though effective, are problematic drugs. They can cause serious side effects like involuntary movement disorders (extrapyramidal symptoms) and neuroleptic malignant syndrome (NMS). Early antipsychotics blocked dopamine, a chemical that makes nerves more excitable, but extrapyramidal symptoms were bad and sometimes permanent. Newer antipsychotics called atypical antipsychotics like Invega, Zyprexa (olanzapine), or Abilify (aripiprazole) block both dopamine and serotonin to calm activity in the brain. Because of their dual action, they are less likely to cause some of the problematic movement disorders such as tremors, involuntary facial movements (tardive dyskinesia), parkinsonism, or restlessness (akathisia).

Although Invega is available as oral tablets and intramuscular injections, patients start on once-daily Invega oral tablets or risperidone. Once patients have taken either Invega or risperidone tablets for a while without debilitating side effects, they can be transitioned to once-monthly injections at higher doses (Invega Sustenna). If those once-monthly injections have been working for at least four months, patients can be transitioned to injections given once every three months (Invega Trinza) or once every six months (Invega Hafyera). 

• Standard Invega dosage for schizophrenia: 3–12 mg oral tablet once daily OR 39–234 mg Invega Sustenna injection once monthly OR 273–819 mg Invega Trinza injection once every three months OR 1,092–1,560 mg Invega Hafyera injection twice yearly

• Maximum Invega dosage for schizophrenia: 12 mg oral tablet once daily OR 234 mg Invega Sustenna injection once monthly OR 819 mg Invega Trinza injection once every three months OR 1,560 mg Invega Hafyera injection twice yearly

Invega dosage for schizoaffective disorder

Schizoaffective disorder is diagnosed when a person has both schizophrenia and a major mood episode such as depression or mania. Healthcare professionals are uncertain about the incidence of schizoaffective disorder, though the diagnosis accounts for 10% to 30% of psychosis admissions.

Schizoaffective disorder is primarily treated with some combination of antipsychotic medications, mood stabilizers, antidepressants, and therapy. Antipsychotic medications like Invega control psychotic and behavioral symptoms, while mood stabilizers and antidepressants help control depressive or manic episodes.

People with schizoaffective disorder will start with Invega tablets or risperidone and can transition to once-monthly Invega Sustenna injections. Invega Trinza and Invega Hafyera are not FDA-approved to treat schizoaffective disorder.

• Standard Invega dosage for schizoaffective disorder: 3–12 mg oral tablet once daily OR 39–234 mg Invega Sustenna injection once monthly

• Maximum Invega dosage for schizoaffective disorder: 12 mg oral tablet once daily OR 234 mg Invega Sustenna injection once monthly

Invega dosage for children

Invega oral tablets are FDA-approved to treat schizophrenia in children 12 years of age and older. Doses vary depending on the child’s response to the drug and its side effects. The starting oral pediatric dose is 3 mg daily. Maximum dosages vary by weight. 

• Standard Invega dosage for schizophrenia in children ages 12 and older and weighing less than 51 kg: 3–6 mg once daily 

• Standard Invega dosage for schizophrenia in children ages 12 and older and weighing 51 kg or more: 3–12 mg once daily 

• Maximum Invega dosage for children ages 12 and older: 6 mg once daily (< 51kg) or 12 mg once daily (≥ 51 kg)

Invega dosage restrictions

People with kidney problems require lower Invega doses. No dosage adjustments are required for people with liver dysfunction. 

• Patients with mild renal impairment (creatinine clearance between 50 mL/ min and 80 mL/min): 3 mg tablet once daily starting dose, 6 mg tablet maximum dose

• Patients with moderate to severe renal impairment (creatinine clearance between 10 mL/ min and 50 mL/min): 1.5 mg tablet once daily starting dose, 3 mg tablet maximum dose

• Patients with severe renal impairment (creatinine clearance <10 mL/min): Avoid use

Invega Sustenna, Invega Trinza, and Invega Halfyera injections will also require lower starting and maximum doses in people with kidney dysfunction. Healthcare professionals will make those reductions following the manufacturer’s directions.

How to take Invega

People have the option of taking Invega oral tablets once per day or getting long-lasting intramuscular injections. 

The extended-release tablet is taken like most other tablets:

• Take Invega extended-release tablets exactly as directed. Do not use more than prescribed or take doses of more than one pill per day.

• Invega can be taken with or without food. However, side effects may be more likely if Invega is taken with food.

• Swallow the tablet whole with a drink of water. Do not crush, break, or chew the tablet.

• Store Invega tablets at room temperature in a closed container that is out of the reach of children.

Healthcare professionals administer intramuscular injections, so it’s important to keep all appointments:

• Injections are made into the shoulder (deltoid muscle) or buttocks (gluteal muscle)

• When starting Invega Sustenna, the second injection must be administered one week after the first dose. Do not miss this appointment.

• Missing the second dose may involve getting an extra third initiation dose or repeating the first two initiation dosages.

• After the first two initiation doses, people will transition to a maintenance dose given once a month, once every three months, or once every six months.

• Do not miss appointments for maintenance doses. If too much time goes by, a missed dose may require starting again with two initiation doses.

Invega dosage FAQs

How long does it take Invega to work?

In clinical trials, participants experienced significant changes in schizophrenia symptoms in about two months. 

What happens if I miss a dose of Invega?

Ask the prescriber what to do if an Invega tablet is missed. Do not miss appointments for Invega injections. The injections may need to be restarted with two initiation doses. 

How long can you take Invega?

Invega is intended as a long-term treatment to prevent the relapse of schizophrenia symptoms. In a long-term clinical study, 85% of participants did not experience any relapse in 469 days. That study did not find side effects or complications due to long-term use. The most common side effects people experienced during this study were weight gain, headache, and insomnia.

What interacts with Invega?

Invega has several drug interactions that may cause problems. Tell the prescriber and your pharmacist about all drugs being taken, including prescription drugs, over-the-counter medications, alternative remedies, and supplements, particularly:

• Drugs used to treat mental health issues, including other antipsychotics, antidepressants, anti-anxiety medications, mood stabilizers, or similar drugs

• Drugs that work on the central nervous system, like anticonvulsants or muscle relaxants

• Drugs that make you sleepy, like narcotic pain medications, tranquilizers, antihistamines, sleeping pills, and so on

• Drugs that make you feel faint or lightheaded (syncope) when standing up (orthostatic hypotension)

• Drugs that affect heart rhythms, particularly drugs that cause QT prolongation

• The antiseizure drug carbamazepine

What happens when you mix Invega and alcohol?

Avoid drinking alcohol or using cannabinoid products when taking Invega or any other antipsychotic. The alcohol or CBD may worsen many of the side effects of Invega, such as somnolence. 

Is it safe to take Invega during pregnancy?

Healthcare professionals are cautious about using antipsychotics in pregnant women, particularly in the last trimester. There is a risk that a baby exposed to antipsychotic drugs late in pregnancy will experience significant adverse reactions, including withdrawal symptoms, involuntary muscle movements, agitation, rigid muscles, sleepiness, tremors, breathing problems, or feeding problems. Some newborns quickly recover and others might require intensive care and prolonged hospitalization. 

Sources

• Invega drug summary, Prescriber’s Digital Reference (PDR)

• Invega Sustenna HCP, Janssen Pharmaceuticals, Inc.

• Invega paliperidone palmitate extended-release tablets prescribing information, DailyMed (NIH National Library of Medicine)

• Invega Hafyera paliperidone palmitate extended-release injection prescribing information, DailyMed (NIH National Library of Medicine)

• Invega Sustenna paliperidone palmitate injection prescribing information, DailyMed (NIH National Library of Medicine)

• Invega Trinza paliperidone palmitate extended-release injection prescribing information, DailyMed (NIH National Library of Medicine)

• Schizoaffective disorder, StatPearls

• Schizophrenia, StatPearls