Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Xospata (Gilteritinib). If you are concerned about side effects, discuss the risks and benefits of Xospata (Gilteritinib) with your doctor.

The following side effects have been reported by at least 1% of people taking Xospata (Gilteritinib). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• Constipation
• cough
• decreased appetite
• dizziness
• fatigue
• general feeling of being unwell
• headache
• joint pain
• muscle pain
• nausea
• skin rash
• strange taste in the mouth
• stomach pain
• swelling in the feel, ankles, hands
• vomiting
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• fainting
• Fever
• fluid build-up around the lungs (e.g., chest pain, cough, hiccups, rapid breathing)
• increased frequency or severity of infections (symptoms may include fever or chills, severe Diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• inflammation of the mouth and lips
• low magnesium levels in the blood (e.g., weakness, tremor, muscle cramps, seizures)
• low potassium levels in the blood (e.g., weakness, fatigue, muscle cramps, irregular heartbeat)
• pain, numbness, or weakness in the hands and feet
• signs of Anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding
• signs of heart problems (e.g., fast, irregular heartbeat or pulse, chest pain, sudden weight gain, difficulty breathing, leg swelling)
• signs of kidney failure (e.g., decreased urine production, swelling, fatigue, abdominal pain)
• signs of kidney problems (e.g., change in the amount or colour of urine, increased urination at night, blood in the urine, swelling in the feet or legs)
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• fluid build-up around the heart (e.g., fever, fatigue, muscle aches, shortness of breath, nausea, vomiting, diarrhea, fast or pounding heartbeat, light-headedness)
• signs of an allergic reaction (e.g., wheezing, tightness in chest, troubled breathing, shortness of breath, or cough)
• signs of posterior reversible encephalopathy syndrome (e.g., headache, seizures, weakness, confusion, high blood pressure, vision changes, difficulty thinking clearly)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Xospata (Gilteritinib).

Each light yellow, round-shaped, film-coated tablet debossed with the Astellas logo and "235" on the same side contains 40 mg of Xospata (Gilteritinib) as Xospata (Gilteritinib) fumarate. Nonmedicinal ingredients: hydroxypropyl cellulose, hypromellose, low-substituted hydroxypropyl cellulose, magnesium stearate, mannitol, polyethylene glycol, talc, titanium dioxide, and ferric oxide.

Do not take Xospata (Gilteritinib) if you are allergic to Xospata (Gilteritinib) or any ingredients of the medication.

There may be an interaction between Xospata (Gilteritinib) and any of the following:

• antiarrhythmics (e.g. Amiodarone, Dronedarone, procainamide, quinidine, Sotalol)
• antihistamines (e.g., bilastine, Desloratadine)
• antipsychotics (e.g., Chlorpromazine, Clozapine, Haloperidol, Olanzapine, Pimozide, Quetiapine, Risperidone, thioridazine)
• Apalutamide
• Aprepitant
• "azole" antifungals (e.g., fluconazole, itraconazole, ketoconazole, Voriconazole)
• Bosentan
• Carbamazepine
• Carvedilol
• Ceritinib
• chloroquine
• Cobicistat
• conivaptan
• Crizotinib
• Dabrafenib
• Deferasirox
• Diltiazem
• Domperidone
• Doxepin
• efavirenz
• Elagolix
• Enzalutamide
• Flibanserin
• grapefruit juice
• HIV protease inhibitors (e.g., atazanavir, darunavir, indinavir, lopinavir, ritonavir)
• lumacaftor and Ivacaftor
• macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
• Methadone
• mifepristone
• Mitotane
• Modafinil
• Ondansetron
• Phenobarbital
• Phenytoin
• primidone
• other protein kinase inhibitors (e.g. Dasatinib, imatinib, Vandetanib, Vemurafenib)
• quinine
• quinolone antibiotics (e.g., levofloxacin, moxifloxacin)
• rifabutin
• rifampin
• St. John's wort
• Sarilumab
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Fluvoxamine, Sertraline)
• siltuximab
• Stiripentol
• Tocilizumab
• Verapamil

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Xospata (Gilteritinib). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Xospata (Gilteritinib).

Birth control: Women and men who are taking Xospata (Gilteritinib) should use effective birth control. Women should use effective birth control while taking Xospata (Gilteritinib) and for at least 6 months after taking the last dose. Men taking Xospata (Gilteritinib) and whose partners may become pregnant should use effective birth control while taking Xospata (Gilteritinib) and for at least 4 months after taking the last dose.

Driving: Xospata (Gilteritinib) can cause severe dizziness or fainting which may affect your ability to safely drive or operate machinery. Do not drive or perform hazardous tasks such as operating machinery until you know how Xospata (Gilteritinib) affects you.

Grapefruit juice: Grapefruit juice affects how Xospata (Gilteritinib) is removed from the body and may cause the medication to build up in the body, causing side effects. Do not drink grapefruit juice while taking Xospata (Gilteritinib).

Heart rhythm: Xospata (Gilteritinib) can cause changes to the normal rhythm of the heart, including an irregular heartbeat called QT prolongation. QT prolongation is a serious life-threatening condition that can cause fainting, seizures, and sudden death. If you are at risk for heart rhythm problems (e.g., people with heart failure, Angina, low potassium or magnesium levels), discuss with your doctor how Xospata (Gilteritinib) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Xospata (Gilteritinib), and whether any special monitoring is needed.

Liver function: If you have liver problems, discuss with your doctor how Xospata (Gilteritinib) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Xospata (Gilteritinib), and whether any special monitoring is needed.

Pancreatitis: Xospata (Gilteritinib) can cause the pancreas to become inflamed. If you have a history of pancreatitis, discuss with your doctor how Xospata (Gilteritinib) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Xospata (Gilteritinib), and whether any special monitoring is needed.

Report signs of pancreatitis such as abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, or swollen abdomen to your doctor immediately.

Posterior reversible leukoencephalopathy syndrome (PRES): This is a rare disease of the brain that may occur when using medications like Xospata (Gilteritinib). Make sure your doctor knows if you have experienced this before. If you experience signs and symptoms of RPLS, such as headache, seizures, change in awareness or consciousness, or vision changes, contact your doctor immediately.

Respiratory problems: Cases of severe inflammation of the lung and heart have been reported with Xospata (Gilteritinib). These lung and heart problems can be life-threatening and should be considered a medical emergency. If you experience fever, shortness of breath, swelling of the ankles and feet, sudden weight gain, or painful breathing, seek immediate medical attention.

Pregnancy: Xospata (Gilteritinib) should not be used during pregnancy due to the risk that it may cause harm to the unborn baby. If you become pregnant while taking Xospata (Gilteritinib), contact your doctor immediately.

Breast-feeding: It is not known if Xospata (Gilteritinib) passes into breast milk. If you are a breast-feeding mother and are taking Xospata (Gilteritinib), it may affect your baby. Women are advised to avoid breast-feeding while taking Xospata (Gilteritinib) and for 2 months after taking the last dose.

Children: The safety and effectiveness of using Xospata (Gilteritinib) have not been established for children.