Rexulti dosage, forms, and strengths

Rexulti is a brand-name prescription drug approved by the U.S. Food and Drug Administration (FDA) to treat major depressive disorder (MDD) in adults, schizophrenia in adults and children 13 years of age and older, and agitation related to dementia in people with Alzheimer’s disease. Brexpiprazole, the active ingredient in Rexulti, is an atypical antipsychotic that works by slowing down brain activity. People prescribed Rexulti take one dose per day as a tablet. The doses will vary, and the dosage is often ramped up, but the recommended daily dosage for many conditions is about 2 mg. 

Rexulti forms and strengths

Like many medications prescribed for mental health conditions, Rexulti comes in a range of dosage strengths. Clinicians will steadily increase the dose at the beginning of treatment to arrive at the most effective dosage. During treatment, healthcare providers may regularly change doses.

• Tablets: 0.25 milligrams (mg), 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg

Rexulti dosage for adults

The FDA has approved Rexulti as an adjunctive therapy for major depressive disorder in adults as well as a treatment for schizophrenia. The FDA has also approved it to treat agitation in Alzheimer's patients experiencing dementia. Rexulti tablets are taken once daily with a meal or on an empty stomach for all three medical conditions.

Rexulti dosage for depression

For depression, atypical antipsychotics like Rexulti are only prescribed when more routine antidepressants alone don’t produce symptom remission, a condition called treatment-resistant depression. In those cases, a psychiatrist may add a daily dose of Rexulti or other antipsychotic medication like Abilify (aripiprazole) alongside other antidepressants. This combination does produce symptom improvement in some people. 

However, side effects are a significant concern. Commonly experienced adverse reactions include drowsiness, weight gain, low blood pressure (orthostatic hypotension), fainting, falling, high blood sugar (hyperglycemia), high cholesterol and fats, low white blood cell counts, restless movements (akathisia), body temperature dysregulation, tardive dyskinesia (involuntary facial movements), compulsive behaviors (such as gambling or sexual urges), worsening depression, suicidal thoughts, and neuroleptic malignant syndrome (NMS).

• Standard Rexulti dosage for the adjunctive treatment of major depressive disorder: One 2 mg tablet taken once per day 

• Maximum Rexulti dosage for the adjunctive treatment of major depressive disorder: 3 mg per day 

Rexulti dosage for schizophrenia

As an antipsychotic, the FDA has approved Rexulti to treat schizophrenia. Healthcare professionals aren’t sure how it works, but clinical studies have shown that Rexulti can significantly improve symptoms and prevent relapses. Side effects are a concern, but this is true of other atypical antipsychotics. 

• Standard Rexulti dosage for schizophrenia: 2–4 mg taken once per day 

• Maximum Rexulti dosage for schizophrenia: 4 mg per day 

Rexulti dosage for Alzheimer’s disease

Rexulti is also used to reduce agitation associated with dementia in older adults with Alzheimer’s disease. Some healthcare providers may prescribe it off-label for other severe behavioral or psychological symptoms of dementia in older adult patients diagnosed with Alzheimer’s. Again, researchers don’t know exactly how Rexulti works to calm agitation. Side effects and drug interactions are a significant concern. The FDA has mandated including a boxed warning concerning the side effects of this medication. This warning warns that there’s an increased risk of death in Alzheimer’s patients with dementia-related psychosis when treated with an antipsychotic.

• Standard Rexulti dosage for agitation associated with dementia in Alzheimer’s patients: 2 mg tablet taken once per day 

• Maximum Rexulti dosage for agitation associated with dementia in Alzheimer’s patients: 3 mg per day 

Rexulti dosage for children

Rexulti is approved by the FDA to treat schizophrenia in adolescents 13 years of age and older. Teens start with a lower dose than adults, although the recommended dosage is similar for both age groups.

• Initial Rexulti pediatric dosage for schizophrenia in children 13 years of age and older: 0.5 mg tablet taken once per day 

• Standard Rexulti pediatric dosage for schizophrenia in children 13 years of age and older: 2–4 mg taken once per day 

• Maximum Rexulti pediatric dosage for schizophrenia in children 13 years of age and older: 4 mg per day 

Rexulti dosage restrictions

Liver disease (hepatic impairment) and kidney disease (renal impairment) do not require changes to the starting or target dosage. Still, the maximum dosage is lower than it is for others. 

• Maximum dosage for renally impaired patients (creatinine clearance < 60 mL/min): 2 mg per day for MDD or Alzheimer’s and 3 mg per day for schizophrenia

• Maximum dosage for moderate to severe hepatic impairment: 2 mg per day for MDD or Alzheimer’s and 3 mg per day for schizophrenia

People who do not metabolize brexpiprazole well also need dosage reductions, although the specific adjustments to the dosage have yet to be specified. Healthcare providers call these people “CYP2D6 poor metabolizers.” CYP2D6 is the liver enzyme that breaks down brexpiprazole and many other drugs. If that enzyme isn’t working well, the drug builds up in the body, increasing the risk of side effects and severe adverse reactions. 

How to take Rexulti

Rexulti is taken daily as a single dose with or without food. 

• Take your medicine as directed. Your dose may need to be changed several times to find what works best.

• This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.

• Do not miss a dose. If a dose is missed, take it as soon as it’s remembered unless it’s almost time for the next dose. In that case, skip the missed dose and take the next dose as scheduled. Do not take extra medicine to make up for a missed dose.

• Do not stop using Rexulti or change the dose without talking to the prescriber. 

• Store the medicine in a closed container at room temperature.

• Keep this medicine out of the reach of children.

Rexulti dosage FAQs

How long does it take Rexulti to work?

In clinical trials, Rexulti showed noticeable reductions in schizophrenia or depression symptoms after one week of treatment, but the maximum effects took about six weeks. For agitation associated with dementia, Rexulti treatment did not show better results than a placebo until four weeks of treatment. Maximum results were hit in 12 weeks.

How long does Rexulti stay in your system?

Rexulti stays in the system for a long time. That’s relevant if side effects or serious side effects occur. When the body metabolizes brexpiprazole, it breaks it down into another substance that works like brexpiprazole. This is called an “active metabolite.” The half-life of brexpiprazole is 91 hours—almost four days. The half-life of its active metabolite is 86 hours—another four days. Side effects of Rexulti can be experienced for this entire time.

What happens if I miss a dose of Rexulti?

It is advisable to set an alarm so that Rexulti is taken on time. Do not miss a Rexulti dose. If you forget a dose, take it when you remember; however, skip the missed dose if you are nearing the next dose. Take a missed dose only on the day it was supposed to be taken. Rexulti is taken once daily, so a good rule of thumb is to take only one daily dose. Take a missed dose only on the day it was supposed to be taken.

How long can you take Rexulti?

Rexulti can be taken for as long as it’s effective and side effects are tolerable. If side effects are too hard to live with, talk to the prescriber about alternative treatments. Sometimes, side effects may require a healthcare professional to stop Rexulti treatment immediately. These include allergic reactions, involuntary facial movements (tardive dyskinesia), or a severe and life-threatening set of neurological changes called neuroleptic malignant syndrome.

How do I stop taking Rexulti?

Patients should not stop Rexulti without first consulting their prescribing healthcare provider. The prescribing information and other physician resources do not indicate that stopping Rexulti will cause withdrawal symptoms or that a steadily decreasing dose is necessary. However, never do it on your own. Always get medical advice from the prescriber first. 

What is the maximum dosage for Rexulti?

For individuals undergoing treatment for major depressive disorder or experiencing agitation associated with Alzheimer's dementia, the maximum daily dosage of Rexulti is 3 mg. The maximum dosage is 4 mg per day for the treatment of schizophrenia.

Can you overdose on Rexulti?

Get emergency medical treatment or call a poison helpline if too much Rexulti is taken. 

Emergency healthcare providers can minimize an overdose if they catch it early enough. Otherwise, healthcare professionals will provide symptom treatment and monitoring. 

What interacts with Rexulti?

Like most antipsychotic drugs, Rexulti has several potentially hazardous drug interactions. No drug combinations are prohibited, but healthcare providers may avoid combining Rexulti with other medications or make dosage adjustments to reduce the risks.

The most concerning drug interactions involve drugs that slow down the metabolism of brexpiprazole and its active metabolite. These drugs are called CYP3A4 inhibitors (such as the antifungal drug ketoconazole and CYP2D6 inhibitors such as quinidine. They’re named after two enzymes in the liver that break down brexpiprazole. The result is increased brexpiprazole in the body, increasing the risk of side effects. Prescribers will reduce the Rexulti dose to avoid problems. This relevance arises because many antidepressants that may be prescribed with Rexulti, such as Paxil (paroxetine) and Prozac (fluoxetine), are potent CYP2D6 inhibitors.

Prescribers also express concern about medications known as CYP3A4 inducers, which accelerate the metabolism of brexpiprazole. These medications make Rexulti less effective, so the prescriber will probably increase the dose to compensate.

What happens when you mix Rexulti and alcohol?

Do not drink when taking Rexulti or other antipsychotic drugs. Drugs like Rexulti have depressive effects on the central nervous system, causing drowsiness, sleepiness, coordination problems, and slow thinking. Falls and injuries are a major concern with Rexulti. Adding alcohol to the mix exacerbates these effects and risks.

Is it safe to take Rexulti during pregnancy?

Doctors can prescribe Rexulti to pregnant women. However, researchers have not studied its safety in pregnant women. What we do know is that using antipsychotics during the third trimester raises the risk that newborns might be born with muscle movement disorders (extrapyramidal symptoms) or withdrawal symptoms, including agitation, muscle problems, tremors, feeding problems, and breathing problems. Some babies recover quickly when this happens, while others may require longer-term hospitalization. 

Is it safe to take Rexulti while breastfeeding?

Healthcare providers can prescribe Rexulti to women who are breastfeeding. There are no studies about how safe or unsafe it is to take Rexulti while breastfeeding. No one knows if brexpiprazole affects lactation, is present in breast milk, or affects a nursing infant.

Sources

• Alzheimer’s treatments and medications, SingleCare

• Depression treatments and medications, SingleCare

• Pharmacotherapies for treatment-resistant depression: How antipsychotics fit in the rapidly evolving therapeutic landscape, The American Journal of Psychiatry

• Rexulti dosing guide, Otsuka

• Rexulti drug summary, Prescriber’s Digital Reference

• Rexulti prescribing information, NIH National Library of