Fostamatinib disodium (Oral)

Fostamatinib is used to treat low platelet levels (thrombocytopenia) in the blood for patients with chronic immune thrombocytopenia (ITP) who have not responded well to previous treatments.

This medicine is available only with your doctor's prescription.

It is very important that your doctor checks your progress at regular visits to ensure this medicine is working properly. Blood tests may be needed to look for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to prevent getting pregnant during treatment with this medicine and for at least 1 month after the last dose. If you think you have become pregnant while using this medicine, tell your doctor right away.

Your blood pressure might get too high while you are using this medicine. This may cause headaches, dizziness, or blurred vision. You might need to measure your blood pressure at home. If you think your blood pressure is too high, call your doctor right away.

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

In deciding to use a medicine, you need to think about the risks of taking it compared to the benefits it will provide. This decision will be made between you and your doctor. For this medicine, consider the following:

Allergies

Tell your doctor if you have ever had any unusual or allergic reactions to this medicine or any other medicines. Also inform your healthcare professional if you have any other allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Studies on the effects of fostamatinib in children have not been done. Its use is not recommended in children. Safety and effectiveness have not been established.

Geriatric

Research so far has not shown any specific problems in older adults that would limit the usefulness of fostamatinib. However, older patients are more likely to experience serious unwanted effects, which may require caution when using fostamatinib.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medicine during breastfeeding. Consider the potential benefits against the potential risks before taking this medicine while breastfeeding.

Interactions with Medicines

Some medicines should not be used together, while others may be used together even if there is a chance of interaction. In these cases, your doctor may adjust the dose or take other precautions. When you are using this medicine, it is especially important for your healthcare professional to know if you are taking any of the medicines listed below. The following interactions have been selected for their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in some cases. If both medicines are prescribed together, your doctor may change the dose or frequency of one or both medicines.

• Abametapir
• Carbamazepine
• Enzalutamide
• Fedratinib
• Fexinidazole
• Fosphenytoin
• Itraconazole
• Lumacaftor
• Mavacamten
• Mitotane
• Omaveloxolone
• Phenobarbital
• Phenytoin
• Primidone
• Rifampin
• Rosuvastatin
• St John's Wort
• Voriconazole

Interactions with Food/Tobacco/Alcohol

Some medicines should not be taken around the time of eating food or certain types of food due to potential interactions. Using alcohol or tobacco with certain medicines may also cause interactions. Talk to your healthcare professional about using your medicine with food, alcohol, or tobacco.

Other Medical Problems

Having other medical problems may affect the use of this medicine. Be sure to tell your doctor if you have any other medical issues, especially:

• Blood clot in your leg or lungs, recent or
• Hypertension (high blood pressure) or
• Infection, recent or
• Liver disease or
• Surgery (e.g., splenectomy)—Use with caution. May cause side effects to worsen.

Along with its necessary effects, a medicine may cause some unwanted effects. Not all of these side effects may happen, but if they do, they may require medical attention.

Check with your doctor right away if any of the following side effects happen:

More common

• Black, tarry stools
• Blurred vision
• Chest pain
• Chills
• Cough
• Diarrhea
• Dizziness
• Fever
• Headache
• Lower back or side pain
• Nervousness
• Painful or difficult urination
• Pale skin
• Pounding in the ears
• Slow or fast heartbeat
• Sore throat
• Stomach pain
• Ulcers, sores, or white spots in the mouth
• Unusual bleeding or bruising
• Unusual tiredness or weakness

Check with your doctor right away if any of the following side effects happen:

More common

• Nausea
• Rash

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Pharmacologic Class: Fostamatinib

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine should come with a patient information leaflet. Read and follow these instructions carefully. Ask your doctor if you have any questions.

You may take this medicine with or without food.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (tablets):For thrombocytopenia: Adults—The starting dose is usually 100 milligrams (mg) 2 times a day. Your doctor may increase your dose as needed. Children—Use is not recommended.

Missed Dose

If you miss a dose of this medicine, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.