Fanapt (iloperidone) is a brand-name oral tablet that’s prescribed to treat schizophrenia and bipolar disorder in adults. As with other drugs, Fanapt can cause side effects, such as dizziness and fatigue.

More common side effects of Fanapt

Fanapt can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Fanapt in clinical trials:

Mild side effects of Fanapt

Mild side effects can occur with Fanapt use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Fanapt’s prescribing information.

Mild side effects that have been reported with Fanapt include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Fanapt and want to tell the FDA about it, visit MedWatch.

* An allergic reaction is possible after using Fanapt. To learn more, see the “Side effect specifics” section below.

Serious side effects of Fanapt

Fanapt may cause serious side effects, but they aren’t common. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Fanapt’s prescribing information.

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

Serious side effects that have been reported and their symptoms include:

  • Changes in metabolism, which may lead to serious health problems. These can include:
  • Blood disorders, such as leukopenia (low white blood cell levels) or anemia (low red blood cell levels). Symptoms can include:
    • fatigue
    • fever
    • frequent infections
    • paleness
  • Heart problems, such as long QT syndrome (a change in heart rhythm) or tachycardia (rapid heart rate). Symptoms can include:
  • Hyperprolactinemia (high prolactin levels). Symptoms can include:
  • Tardive dyskinesia (involuntary muscle movements caused by certain medications). These involuntary movements typically occur in your face and can include:
    • lip smacking
    • sticking out your tongue
    • excessive blinking
    • jaw movements
  • Neuroleptic malignant syndrome (a serious reaction to certain medications that affect your nervous system). Symptoms can include:
    • muscle stiffness
    • fever
    • changes in heart rate
    • confusion
  • Priapism (prolonged erection). Symptoms can include:
    • an erection that lasts more than 4 hours
    • pain in your penis that may get worse over time
  • Changes in thinking, motor skills, or judgment.
  • Seizures.
  • Dysphagia (trouble swallowing). This could lead to aspiration pneumonia, which is an infection that can happen after inhaling liquids or foods instead of swallowing them.
  • Problems with managing body temperature.
  • Orthostatic hypotension.*
  • Increased risk of death in certain older adults.†
  • Severe allergic reaction.‡

* For more information about this side effect, see “Side effect specifics” below.

† Fanapt has a boxed warning for this side effect. A boxed warning is the most serious warning from the FDA. To learn more, see the “Side effect specifics” section below.

‡ An allergic reaction is possible after using Fanapt. To learn more, see the “Side effect specifics” section below.

Side effect specifics

Learn more about some of the side effects that Fanapt may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Fanapt.

Increased risk of death in certain older adults

Fanapt has a boxed warning for increased risk of death in certain older adults. A boxed warning is the most serious warning from the FDA.

Antipsychotic drugs, including Fanapt, may increase the risk of death when used in older adults to treat psychosis related to dementia.

Fanapt is used to treat symptoms of schizophrenia, such as psychosis (a loss of touch with reality). Dementia can also cause symptoms of psychosis. However, Fanapt is not approved to treat dementia-related psychosis.

What you can do

Because of an increased risk of death, doctors typically won’t prescribe Fanapt to treat dementia-related psychosis in older adults. Talk with your doctor to learn more about this warning or other treatment options available for dementia-related psychosis.

Orthostatic hypotension

Orthostatic hypotension was a commonly reported side effect of Fanapt in clinical trials. This is when there is a sudden drop in blood pressure when changing positions, such as when moving from sitting to standing. This side effect is more likely to occur if the dose of Fanapt is increased too quickly. Symptoms can include:

  • lightheadedness
  • dizziness
  • rapid heart rate
  • fainting

What you can do

Your doctor will likely start you on a low dose and slowly increase the dose to reduce your risk of orthostatic hypotension. Be sure to drink plenty of liquids to avoid dehydration, which can increase your risk of this side effect. To help prevent or manage orthostatic hypotension, there are a few other things you can try:

  • When getting out of bed, sit on the edge of the bed for a minute before standing up.
  • Avoid strenuous activity during hot weather.
  • Limit alcohol consumption.

It’s important to tell your doctor if you have a history of heart problems. Also be sure to tell them about all the medications you take before you start Fanapt. Your doctor may want to monitor you more closely. If you have episodes of orthostatic hypotension that are bothersome or are happening more often, tell your doctor right away.

Allergic reaction

As with most drugs, Fanapt can cause an allergic reaction in some people.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Fanapt. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Precautions for Fanapt

Below is important information about precautions to consider before you start treatment with Fanapt.

Boxed warning: Increased risk of death in certain older adults

This drug has a boxed warning for increased risk of death in certain older adults. A boxed warning is the most serious warning from the FDA. For details, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before you take Fanapt. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These include:

Seizure disorder: If you have a seizure disorder or a history of seizures, talk with your doctor before you start taking Fanapt. Taking Fanapt may increase your risk of seizures and could worsen your condition. Your doctor can determine whether treatment with Fanapt is the right choice for you.

Diabetes: The use of Fanapt can cause hyperglycemia (high blood sugar levels). If you have diabetes, it may be harder to manage your blood sugar during treatment with Fanapt. Your doctor will likely monitor your blood sugar more closely while you’re taking the medication. They may need to adjust your diabetes medications if your blood sugar is high.

Long QT syndrome: The use of Fanapt can cause a change in heart rhythm or heart rate that is known as long QT syndrome. If you have a history of heart problems or have congenital long QT syndrome, talk with your doctor before taking Fanapt. You may be at an increased risk for heart problems. Your doctor can decide whether Fanapt is a safe treatment option for you or may recommend a different medication for you.

Liver problems: Tell your doctor if you have liver problems, such as cirrhosis or liver failure. Fanapt isn’t recommended in people with severe liver problems. If you have moderate liver problems, your doctor will likely prescribe a lower dose of Fanapt for you.

Heart problems: If you have heart problems, such as an abnormal heart rhythm or heart failure, you may be at a higher risk for heart problems during treatment with Fanapt. Be sure to tell your doctor about any heart problems you have before taking Fanapt.

High or low blood pressure: Fanapt can cause changes in blood pressure. Tell your doctor if you have either high or low blood pressure. Taking Fanapt can worsen your condition. Talk with your doctor to determine whether Fanapt is a safe treatment option for you.

Low potassium or magnesium levels: If you have low potassium or magnesium levels or had them in the past, you may be at a higher risk for heart problems such as long QT syndrome. Your doctor will want to monitor your potassium and magnesium levels before and during treatment with Fanapt.

High cholesterol: Fanapt may increase your cholesterol or triglyceride levels. If you have high cholesterol or triglycerides, taking Fanapt can further increase them. Your doctor will likely want to monitor your cholesterol during treatment with Fanapt. They may need to prescribe a cholesterol medication to reduce the risk of further complications.

Trouble managing body temperature: Treatment with Fanapt can affect how your body manages body temperature. Conditions such as exposure to extreme heat, dehydration, or strenuous exercise can increase the risk of an elevation in body temperature. If you’re prone to these conditions, talk with your doctor about the risks and benefits of taking Fanapt.

Allergic reaction: If you’ve had an allergic reaction to Fanapt or any of its ingredients, your doctor will likely not prescribe Fanapt. Ask your doctor what other medications may be better options for you.

Pregnancy or breastfeeding: Fanapt may not be safe to take if you are pregnant or breastfeeding your child. Talk with your doctor before taking Fanapt if you’re pregnant, planning to become pregnant, or breastfeeding. They can discuss the risks and benefits of using Fanapt while pregnant or breastfeeding.

If you become pregnant while taking Fanapt, you and your doctor should consider reporting your pregnancy to the National Pregnancy Registry for antipsychotic drugs. This registry helps gather information about how exposure to these drugs may affect pregnancy outcomes. For more information, you can call 866-961-2388, visit the website, or talk with your doctor.

Alcohol consumption: You should not drink alcohol during treatment with Fanapt. Alcohol can worsen your condition or increase the risk of certain side effects, such as sleepiness. Talk with your doctor if you have questions about alcohol use while taking Fanapt.

When to talk with your doctor

Like most medications, Fanapt can cause mild and serious side effects. Many side effects are mild and may go away as your body adjusts to the drug. However, some side effects may be severe and require treatment. Talk with your doctor if you develop side effects that are bothersome or serious.

If you’d like to learn more about Fanapt, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

  • More information about Fanapt: For details about other aspects of Fanapt, refer to this article.
  • Dosage: For information about the dosage of Fanapt, view this article.

Disclaimer: Medical News Today 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.