Midostaurin is used to treat certain types of blood cell cancer (acute myeloid leukemia-AML, mast cell leukemia-MCL) or an immune system disorder (mastocytosis). It works by slowing or stopping the growth of cancer cells and certain immune system cells (mast cells).

Read the Patient Information Leaflet if available from your pharmacist before you start taking midostaurin and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with food as directed by your doctor, usually twice daily (every 12 hours). Swallow the capsules whole. Do not open or crush the capsules.

The dosage is based on your medical condition and response to treatment. For certain conditions, you may not need to take this medication every day (for example, some people are directed to take the medication for 2 weeks, then stop for 2 weeks). Follow your doctor's instructions carefully.

Your doctor should instruct you to take other medications to prevent nausea and vomiting. Take those medications as directed.

If you vomit after taking a dose, do not take another dose at that time. Take your next dose on your usual dosing schedule.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.

Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.

Avoid eating grapefruit or drinking grapefruit juice while using this medication unless your doctor or pharmacist says you may do so safely. Grapefruit can increase the chance of side effects with this medicine. Ask your doctor or pharmacist for more details.

Nausea/vomiting, diarrhea, stomach/abdominal pain, mouth sores, constipation, hemorrhoids, headache, dizziness, tiredness, muscle/joint pain, or trouble sleeping may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• increased thirst/urination
• signs of kidney problems (such as change in the amount of urine)
• signs of infection (such as sore throat that doesn't go away, fever)
• easy bruising/bleeding
• unusual tiredness
• vomit that is bloody or looks like coffee grounds
• black/tarry stool

Get medical help right away if you have any very serious side effects, including:

• symptoms of lung problems (such as cough, shortness of breath, chest pain)
• fast/irregular heartbeat
• severe dizziness
• fainting

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking midostaurin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• lung/breathing problems

Midostaurin may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using midostaurin, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions:

• certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG)
• family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death)

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using midostaurin safely.

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using midostaurin. Midostaurin may harm an unborn baby. Your doctor should order a pregnancy test within 7 days before you start this medication. Men and women using this medication should ask about reliable forms of birth control during treatment and for 4 months after the last dose. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this drug and for 4 months after the last dose. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Other medications can affect the removal of midostaurin from your body, which may affect how midostaurin works. Examples include rifamycins (such as rifabutin), St. John's wort, drugs used to treat seizures (such as carbamazepine, phenytoin), among others.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lab and/or medical tests (such as liver function, complete blood count, blood mineral levels) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store in the original package at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.