Brexpiprazole (Rexulti)

What it treats

Brexpiprazole is approved by the U.S. Food and Drug Administration to treat schizophrenia in adults, to be used as an add-on to an antidepressant for major depressive disorder, and to treat agitation associated with Alzheimer dementia. The Alzheimer agitation indication is newer and carries a boxed warning that also applies to all antipsychotics in this population, the risk of death is increased in elderly patients with dementia-related psychosis. Any decision to use brexpiprazole for that reason involves a careful family conversation about benefits and risks.

When brexpiprazole is prescribed for depression, that does not mean the diagnosis has changed to psychosis. It is added at a low dose alongside an antidepressant that has helped only partway.

How it works

Brexpiprazole is an atypical antipsychotic, but it works differently from most of them. Nerve cells in the brain pass messages using chemical messengers, and dopamine is one of them. Most antipsychotics simply block dopamine activity. Brexpiprazole is a dopamine partial agonist, which means it dampens dopamine activity when levels are high and modestly supports it when levels are low.

That mixed action is similar to what aripiprazole does, and the two medications are structurally related. Brexpiprazole has been described as having a somewhat "smoother" receptor profile, it engages some serotonin and adrenaline receptors differently, and in practice it tends to cause a bit less akathisia (restlessness) than aripiprazole for many people. How that translates into mood and symptom benefit is not fully understood, and it is worth being honest about that.

Receptor mechanism (detail)

Brexpiprazole is a D2 and 5-HT1A partial agonist and a 5-HT2A, α1B, and α2C antagonist. It is structurally related to aripiprazole, but the receptor-binding profile is not identical. Brexpiprazole has lower intrinsic activity at the D2 receptor than aripiprazole does, and stronger action at some serotonin and adrenaline receptors. In clinical practice, that translates into somewhat less akathisia than aripiprazole and a slightly different early tolerability profile, though the two medications are used for overlapping conditions and behave more similarly than differently.

Potency and typical dosing pattern

Ranges are typical framework only, not a prescription for any individual. Brexpiprazole is high-potency by milligram, small doses do meaningful work.

For schizophrenia, a common range is 2 to 4 mg once daily, sometimes up to 4 mg. For depression add-on, doses run lower, usually 1 to 3 mg once daily. For agitation in Alzheimer dementia, doses run 2 to 3 mg once daily. Brexpiprazole is taken once a day with or without food. The prescriber sets and adjusts the dose based on response, side effects, and other medications.

Safety monitoring

• Metabolic labs. Weight and BMI at baseline, weeks 4, 8, and 12, then quarterly. Fasting glucose or HbA1c and a lipid panel at baseline, three months, and at minimum annually. Brexpiprazole's metabolic risk is lower than olanzapine or clozapine, but it is not zero.
• Blood pressure at baseline and periodically.
• Akathisia and other movement effects. Ask about restlessness at every early visit. Rates are lower than with aripiprazole but still notable. An involuntary-movement screen (AIMS) every six months looks for tardive dyskinesia over the long term.
• In dementia agitation use. The boxed warning for increased mortality in elderly dementia patients applies directly. A specific patient-and-family conversation about that risk is part of good practice before starting and during ongoing use.
• Prolactin usually stays normal or low; check only if symptoms suggest it.

Metformin co-commencement. Aoife Carolan / Schizophrenia Bulletin guideline.

A clinical guideline led by Aoife Carolan strongly recommends co-commencing metformin alongside high-risk antipsychotics like olanzapine or clozapine. This proactive approach helps mitigate severe metabolic side effects, significantly reducing antipsychotic-induced weight gain and improving insulin resistance. The Schizophrenia Bulletin guideline states that when prescribing olanzapine or clozapine, metformin should be initiated immediately to prevent weight gain and cardiometabolic issues. Brexpiprazole is lower metabolic risk under the guideline; metformin is recommended if weight rises by more than 3 percent of pre-medication weight or if other cardiometabolic conditions are present.

Typical titration used in the guideline: 500 mg once daily → 500 mg twice daily after one week → 500 mg increments every two weeks as tolerated → up to 1000 mg twice daily by about week six. Contraindicated with eGFR below 30 mL/min/1.73 m²; renal function is checked annually and metformin is held during acute illness or dehydration.

Source: Carolan A, et al. Metformin for the Prevention of Antipsychotic-Induced Weight Gain: Guideline Development and Consensus Validation. Schizophrenia Bulletin. 2025;51(5):1193 to 1203.

What to expect

Common side effects

Most people get some side effects. The common ones include:

• Restlessness or an inability to sit still. This is called akathisia. Rates are lower than with aripiprazole but still worth reporting.
• Mild weight gain in some people.
• Sedation or feeling slowed down.
• Dizziness, especially on standing.
• Headache.

Akathisia is worth flagging early, because it is treatable. A prescriber may lower the dose, slow the pace of increases, or add a medication to settle it. If a side effect is severe, or it is not improving, that is a conversation to have with the prescriber rather than a reason to stop on your own.

Serious side effects and warnings

Serious problems are uncommon, but a few are worth knowing.

Boxed warning. Brexpiprazole carries an FDA boxed warning that antipsychotics increase the risk of death in older adults with dementia-related psychosis. This warning applies directly when brexpiprazole is used for Alzheimer agitation, and any decision to prescribe it in that setting should involve an explicit conversation about that increased risk. When brexpiprazole is used as an add-on for depression, the antidepressant boxed warning also applies: antidepressants can increase suicidal thoughts and behaviors in children, teenagers, and young adults under 25, especially early in treatment or after a dose change.

• Metabolic effects. Brexpiprazole can cause weight gain and rises in blood sugar and cholesterol. These tend to be modest compared with olanzapine or quetiapine, but they are still monitored over time.
• Tardive dyskinesia. A movement disorder linked to long-term antipsychotic use, involving repetitive involuntary movements, often of the face or mouth. Risk rises with longer use.
• Neuroleptic malignant syndrome. A rare but serious reaction. Signs include high fever, muscle stiffness, confusion, and an unstable heartbeat or blood pressure. It is a medical emergency.
• Impulse-control behaviors. As with other dopamine partial agonists, new compulsive gambling, shopping, eating, or sexual urges have been reported. Any new compulsive behavior should be reported to a prescriber.

This is not medical advice. Any concern about a serious side effect should be discussed with a prescriber promptly.

Sexual side effects

Brexpiprazole has a relatively low rate of sexual side effects compared with some older antipsychotics. It can still affect sex drive or function for some people. If that happens, it is worth raising with a prescriber rather than living with it, because there are usually options.

Weight, appetite, and sleep

Weight gain is possible with brexpiprazole, and it tends to be a bit more than with aripiprazole but less than with olanzapine or quetiapine. Weight, blood sugar, and cholesterol are checked periodically.

Brexpiprazole is less activating than aripiprazole for most people, and it is more likely to cause mild sedation than insomnia. If sleep becomes a problem in either direction, that is worth raising with the prescriber.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual. The right dose is a decision for a prescriber. Ranges are typical framework only, not a prescription for any individual.

Brexpiprazole comes as oral tablets. It is taken once a day with or without food. The prescriber chooses a starting dose and adjusts it gradually based on how a person responds and tolerates it. Doses for a depression add-on are lower than doses for schizophrenia.

Missed doses and interactions

If you miss a dose, the general guidance is to take it when you remember, unless it is almost time for the next dose. In that case, skip the missed dose and carry on. Don't take two doses to make up for one.

Brexpiprazole is processed by liver enzymes that other medications can speed up or slow down. Strong inhibitors and strong inducers of the CYP3A4 or CYP2D6 enzymes require a dose change. Because of that, the prescriber and pharmacist need a full list of your medications and supplements, including over-the-counter ones. Alcohol is not formally prohibited, but it can worsen side effects and is generally best limited.

Stopping and tapering

Stopping brexpiprazole should be gradual and planned with a prescriber. The body adjusts to the medication over time, and stopping suddenly can cause discomfort or a return of the symptoms it was treating. A prescriber can step the dose down over time in a way that fits the situation.

Pregnancy and breastfeeding

This is an area where individual circumstances matter and the decision belongs with a clinician. Untreated schizophrenia and depression carry their own risks during pregnancy, and brexpiprazole also passes into breast milk. Anyone who is pregnant, planning a pregnancy, or breastfeeding should talk it through with their prescriber so the specific risks and benefits can be weighed for their situation. This is not medical advice.

Cost and generic availability

Brexpiprazole is currently available under the brand name Rexulti. Generic availability is limited depending on market and year, and brand-name pricing tends to be substantially higher than for older antipsychotics. Insurance coverage and manufacturer copay programs vary, the pharmacist and prescriber can help identify options.

Common questions

How is it different from aripiprazole? Brexpiprazole is a close cousin of aripiprazole. Both are dopamine partial agonists, and they are used for overlapping conditions. In practice, brexpiprazole tends to cause less akathisia and less early activation than aripiprazole, and it is somewhat more likely to cause mild sedation or slight weight gain. Which one fits a given person is a prescriber judgment.

Why is it used for Alzheimer agitation? Agitation in Alzheimer dementia is a common and difficult problem. Brexpiprazole is one of the medications with an FDA approval for that use, based on clinical trials. It is not a cure for dementia, and the risks are real, which is why it is only used after careful discussion of alternatives.

What about the elderly dementia warning? All antipsychotics, including brexpiprazole, carry a boxed warning that they increase the risk of death in older adults with dementia-related psychosis. When brexpiprazole is used for Alzheimer agitation, that warning still applies. Prescribers weigh that risk against the harm of severe untreated agitation, and the conversation belongs with the patient and family.

Will it make me gain weight? Some weight gain is possible, but it tends to be modest compared with olanzapine or quetiapine. Weight, blood sugar, and cholesterol are monitored over time.

Questions to ask your prescriber

• What are we hoping this treats, and how will we know it's working?
• Which side effects should I expect early, and which ones should I call about?
• If this is for a family member with dementia, what does the boxed warning mean for us?
• How long should I plan to take it?
• If we decide to stop it later, how would we do that safely?

Sources

This guide draws on current prescribing information and public health references. It is reviewed for clinical accuracy and updated as guidance changes, and current as of June 8, 2026.

• U.S. Food and Drug Administration. Prescribing information (DailyMed).
• MedlinePlus, U.S. National Library of Medicine.
• National Institute of Mental Health.
• American Psychiatric Association. Practice Guideline for the Treatment of Patients with Schizophrenia, 3rd edition.
• National Institute for Health and Care Excellence (NICE). CG178, Psychosis and schizophrenia in adults.
• American Diabetes Association / American Psychiatric Association. Consensus Statement on Antipsychotic Drugs and Obesity and Diabetes.
• Carolan A, et al. Metformin for the Prevention of Antipsychotic-Induced Weight Gain: Guideline Development and Consensus Validation. Schizophrenia Bulletin. 2025;51(5):1193 to 1203.