Key Takeaways

  • More common side effects of Rexulti include weight gain, akathisia (feeling of restlessness with uncontrollable urge to move around), drowsiness, and dizziness.
  • Serious side effects of Rexulti include high blood sugar, seizures, low levels of white blood cells, and tardive dyskinesia (uncontrolled body movements).
  • Rexulti has boxed warnings (the most serious FDA warnings) for increased risk of death in certain older adults and risk of suicidal thoughts and behaviors in people ages 24 years or younger.

Rexulti is used to treat the following conditions:

The active ingredient in Rexulti is brexpiprazole. The drug comes as an oral tablet.

Rexulti has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Side effects explained” section.

Keep reading to learn about the common, mild, and serious side effects that Rexulti can cause.

Some people may experience mild or serious side effects during their Rexulti treatment. Examples of Rexulti’s commonly reported side effects include:

  • weight gain (see “Side effects explained” for details)
  • akathisia (feeling of restlessness, such as a constant, uncontrollable urge to move around)
  • drowsiness
  • dizziness

Rexulti can cause mild side effects in some people. Examples of mild side effects that have been reported with Rexulti include:

To learn more about some of these side effects, see the “Side effects explained” section.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And do not stop taking Rexulti unless your doctor recommends it.

Rexulti may cause mild side effects other than the ones listed in this section. See the Rexulti prescribing information for details.

Serious side effects have been reported with Rexulti. These include:

To learn more about some of these side effects, including the boxed warnings, see the “Side effects explained” section.

If you develop serious side effects while taking Rexulti, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medication safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect during treatment with Rexulti and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Allergic reaction

For some people, Rexulti can cause an allergic reaction. But it’s not clear whether this side effect occurred in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should continue Rexulti treatment.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Rexulti, they may have you switch to a different treatment.

Learn more about some of the side effects Rexulti may cause.

Weight gain

Weight gain is possible with Rexulti treatment. In both short-term and long-term studies, this was one of the most common side effects reported in people taking Rexulti.

The amount of weight you might gain with Rexulti can vary. It depends on several factors, including your condition, dosage, other medical conditions, and lifestyle.

What might help

During your Rexulti treatment, your doctor will monitor your weight regularly.

There are things you can do to help prevent or reverse weight gain while you’re taking Rexulti. Some examples include:

  • Choose a balanced diet: If you don’t already, now may be a good time to start monitoring your nutrition. Consider using a calorie-tracking app or journal to track what you’re eating. Keeping track of your foods and portion sizes can help you eat a balanced diet.
  • Talk with a professional: Ask your doctor if they can refer you to a registered dietitian or certified nutritionist. They can provide personalized advice for your specific needs and health goals.
  • Exercise regularly: Consistent physical exercise can help you burn calories and feel good. Talk with your doctor about how you can get started. They can suggest an exercise program that’s safe for your abilities and can help you reach or maintain a weight that’s healthy for you.

If you have questions or concerns about weight gain with Rexulti, talk with your doctor.

Risk of death in certain older adults

Rexulti treatment may increase the risk of death in older adults (ages 65 years and older) who have psychosis that’s related to dementia. (With psychosis, you lose touch with reality and hear or see things that aren’t really there.) Rexulti may also increase the risk of death in people who have Alzheimer’s disease with psychosis that’s related to dementia and doesn’t involve agitation.

Rexulti has a boxed warning for this side effect. A boxed warning is the most serious warning from the FDA. It alerts doctors and patients about a drug’s effects that may be dangerous.

For this reason, Rexulti treatment isn’t recommended for adults ages 65 and older with this condition. In addition, the drug is not approved for the treatment of people who have Alzheimer’s disease with psychosis that’s related to dementia and doesn’t involve agitation.

What might help

If you’re age 65 years or older and have a history of dementia and psychosis, you shouldn’t take Rexulti. Instead, talk with your doctor about other treatment options.

If you have Alzheimer’s disease with psychosis that’s related to dementia and doesn’t involve agitation, you also shouldn’t take Rexulti. You can talk with your doctor to learn about other treatment options.

Risk of suicidal thoughts and behaviors in young adults

Rexulti may raise the risk of suicidal thoughts and behaviors in people ages 24 years or younger. In fact, Rexulti has a boxed warning for this risk. A boxed warning is the most serious warning from the FDA. It alerts doctors and patients about a drug’s effects that may be dangerous.

If you’re in this age range and are taking Rexulti, your doctor will monitor you closely during your treatment. This is especially important when you first start taking the drug and after any dose increases.

Note: Rexulti may be prescribed to certain children ages 13 years and older who have schizophrenia. Your child should only take this drug if their doctor prescribes it.

What might help

If you feel comfortable, consider telling your family or other household members that you’re starting Rexulti. You can explain that this medication is known to raise the risk of suicidal thoughts or behaviors. This way, the people around you can check in with you to see how you’re feeling. They may notice changes in your behavior before you notice them and can encourage you to get help.

If you have thoughts of harming yourself, get medical attention right away. If this occurs, your doctor may recommend that you stop taking Rexulti.

Suicide prevention

If you think someone is at immediate risk of self-harm or hurting another person:

  • Call 911 or your local emergency number.
  • Stay with the person until help arrives.
  • Remove any guns, knives, medications, or other things that may cause harm.
  • Listen, but don’t judge, argue, threaten, or yell.

If you or someone you know is considering suicide, get help from a crisis or suicide prevention hotline. Try the National Suicide Prevention Lifeline at 800-273-8255.

Headache

Some people have experienced headaches during their Rexulti treatment. In most cases, this side effect usually goes away after a few weeks, once your body adjusts to the drug.

What might help

If you’re looking for medication to relieve headaches from Rexulti, an over-the-counter (OTC) pain reliever may help. Some OTC options include aspirin, acetaminophen (Tylenol), or ibuprofen (Advil, Motrin). If you’re not sure which OTC pain reliever is safe for you, talk with your doctor or pharmacist.

Other remedies can also be used to ease headaches. Consider the following tips, which can be used with or without OTC pain relievers.

  • Stay hydrated: Headaches can occur or get worse if you don’t drink enough fluids. Try to drink plenty of fluids throughout the day.
  • Heat therapy:Taking a hot shower or bath or using a heating pad can help relax tense muscles and provide some relief.
  • Exercise: Go for a walk or do another form of exercise. Light to moderate exercise can help release endorphins (brain chemicals) and may help ease your headache pain.
  • Limit screen time: Spending too much time looking at screens can cause or worsen headaches. Consider taking regular screen breaks with the 20-20-20 rule: Every 20 minutes, take a 20-second break to look at something 20 feet away.

If your headaches aren’t relieved with these suggestions or if they become severe, talk with your doctor. They may suggest other ways to relieve headaches from Rexulti.

Insomnia or abnormal dreams

Rexulti may cause insomnia (trouble sleeping) or abnormal dreams in some people.

In studies of Rexulti, insomnia was reported as a common side effect. Abnormal or unusual dreams have also been reported with Rexulti use, but not during studies.

What might help

Insomnia from Rexulti may get better or go away on its own after a few weeks or months. If you’re looking for ways to overcome trouble sleeping while taking Rexulti, here are a few suggestions:

  • Practice good sleep hygiene: Adding certain steps to your routine can help your body prepare for sleep.
  • Avoid caffeine later in the day: For most people, consuming caffeine within 3 to 7 hours of bedtime can cause trouble sleeping.
  • Try an over-the-counter (OTC) sleep aid: Some examples include diphenhydramine (Benadryl, ZzzQuil) and doxylamine (Unisom SleepTabs). If you’re not sure which OTC sleep aid is safe for you, check with your doctor or pharmacist.
  • Consider natural remedies: For some people, it can be helpful to drink chamomile tea or take a melatonin supplement before bedtime. If you’re not sure whether natural remedies are safe for you, talk with your doctor or pharmacist.

If you’re concerned about insomnia or abnormal dreams with Rexulti, talk with your doctor. They may suggest ways to relieve this side effect or recommend changes to your treatment plan.

Learn answers to some frequently asked questions about Rexulti’s side effects.

Do side effects from Rexulti vary by tablet strength (0.25 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg)?

Yes, the risk of developing certain side effects may be greater with higher strengths of Rexulti. In studies of Rexulti, restlessness and akathisia were reported more often in people taking higher strengths than in those taking lower strengths. (With akathisia, you have feelings of restlessness, such as a constant, uncontrollable urge to move around.)

But not all side effects of Rexulti vary by tablet strength. For more details on how often side effects occurred in studies, see Rexulti’s prescribing information.

Will Rexulti make me tired?

It’s possible that Rexulti may make you feel tired. Fatigue (lack of energy) and drowsiness were reported in studies of people taking Rexulti to treat depression.

Keep in mind that for depression, Rexulti is prescribed along with antidepressant medication. Tiredness is a side effect of antidepressants as well.

Tiredness was also reported as a side effect in studies of people taking Rexulti for schizophrenia, but it was less common.

Side effects related to being tired may improve after a few weeks or months of taking Rexulti once your body gets used to the drug. To be safe, you shouldn’t drive or operate heavy machinery when you start taking Rexulti until you see how it makes you feel.

If tiredness from Rexulti doesn’t go away or becomes severe, talk with your doctor.

Can Rexulti cause withdrawal symptoms if I stop my treatment?

In studies, people being treated with Rexulti showed no signs of withdrawal when they stopped taking the drug. But Rexulti may cause withdrawal symptoms in newborn children who were exposed to the drug during the third trimester of pregnancy, according to Rexulti’s prescribing information.

If you’re concerned about Rexulti causing withdrawal and how long withdrawal symptoms may last, talk with your doctor before you stop taking Rexulti.

Rexulti’s prescribing information does not provide details on how long withdrawal symptoms may last in newborn children exposed to the drug. If you have questions about Rexulti withdrawal symptoms in your child, talk with their doctor.

How long do side effects from Rexulti last?

How long you experience side effects from Rexulti can vary. Some side effects may be temporary, while others can be long term.

For most people, the following side effects improve or go away within a few weeks or months:

  • headache
  • indigestion (upset stomach)
  • constipation
  • diarrhea
  • tiredness

Other side effects may last for as long as you take Rexulti. These include akathisia and weight gain.

Some side effects of Rexulti don’t go away on their own. These include hyperglycemia (high blood sugar) and high levels of cholesterol or triglycerides. To treat these side effects, your doctor may recommend long-term management with medication, diet, and exercise, even after you stop taking Rexulti.

If you’re concerned about how long side effects last from Rexulti, talk with your doctor or pharmacist.

This drug comes with several warnings.

Boxed warnings

Rexulti has two boxed warnings. Boxed warnings are the most serious warnings from the FDA. The boxed warnings for Rexulti include:

  • Increased risk of death in certain older adults: Rexulti should not be taken by adults ages 65 years or older who have psychosis that’s related to dementia. This is because Rexulti can raise the risk for stroke and death in certain older adults with this condition. Rexulti should also not be taken by people who have Alzheimer’s disease with psychosis that’s related to dementia and doesn’t involve agitation.
  • Risk of suicidal thoughts and behaviors in young adults: Rexulti may raise the risk of suicidal thoughts and behaviors in people ages 24 years or younger. If you’re in this age range and are taking Rexulti, your doctor will monitor you closely during your treatment. This is especially important when you first start taking the drug and after any dosage changes. If you have thoughts of harming yourself, get medical attention right away.

To learn more about these boxed warnings, see the “Side effects explained” section.

Other precautions

Before taking Rexulti, discuss your health history with your doctor. Rexulti may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

Q:

I’ve heard that weight gain is common with Rexulti. Why does the drug cause weight gain?

Anonymous

A:

Rexulti can affect your body’s metabolism (chemical processes in your body). In studies, people taking Rexulti for either depression or schizophrenia were more likely to gain weight compared with those using a placebo. (A placebo is a treatment with no active drug.)

In addition, people taking Rexulti for depression in studies also experienced increased appetite, which can lead to weight gain.

Your doctor will monitor your weight before and during your Rexulti treatment. If you have concerns about weight gain with this drug, talk with your doctor.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.