Fostamatinib

About This Drug

Fostamatinib is used to treat low platelets in patients with a condition called chronic idiopathic thrombocytopenic purpura (ITP). It is given orally (by mouth).

Possible Side Effects

  • Decrease in the number of white blood cells. This may increase your risk of infection.
  • Tiredness
  • Respiratory infection
  • Chest pain
  • Feeling dizzy
  • Nausea
  • Loose bowel movements (diarrhea)
  • Pain in your abdomen
  • Changes in your liver function
  • High blood pressure
  • Rash

Note: Each of the side effects above was reported in 5% or greater of patients treated with fostamatinib. Not all possible side effects are included above.

Warnings and Precautions

  • Severe high blood pressure
  • Severe diarrhea
  • Fever in the setting of decreased white blood cells, which is a serious condition that can be life-threatening

Note: Some of the side effects above are very rare. If you have concerns and/or questions, please discuss them with your medical team. 

How to Take Your Medication

  • Swallow the medicine whole with or without food.
  • Missed dose: If you vomit or miss a dose, take your next dose at the regular time. Do not take 2 doses at the same time, instead, continue with your regular dosing schedule and contact your physician.
  • Handling: Wash your hands after handling your medicine, your caretakers should not handle your medicine with bare hands and should wear latex gloves.
  • This drug may be present in the saliva, tears, sweat, urine, stool, vomit, semen, and vaginal secretions. Talk to your doctor and/or your nurse about the necessary precautions to take during this time.
  • Storage: Store this medicine in the original container at room temperature. Discuss with your nurse or your doctor how to dispose of unused medicine

Treating Side Effects

  • To decrease infection, wash your hands regularly.
  • Avoid close contact with people who have a cold, the flu, or other infections
  • Take your temperature as your doctor or nurse tells you, and whenever you feel like you may have a fever.
  • Manage tiredness by pacing your activities for the day.
  • Be sure to include periods of rest between energy-draining activities.
  • If you are dizzy, get up slowly after sitting or lying.
  • Drink plenty of fluids (a minimum of eight glasses per day is recommended).
  • If you throw up or have loose bowel movements, you should drink more fluids so that you do not become dehydrated (lack water in the body from losing too much fluid).
  • To help with nausea and vomiting, eat small, frequent meals instead of three large meals a day. Choose foods and drinks that are at room temperature. Ask your nurse or doctor about other helpful tips and medicine that is available to help stop or lessen these symptoms. 
  • If you get diarrhea, eat low-fiber foods that are high in protein and calories and avoid foods that can irritate your digestive tracts or lead to cramping.
  • Ask your nurse or doctor about medicine that can lessen or stop your diarrhea.
  • Keeping your pain under control is important to your well-being. Please tell your doctor or nurse if you are experiencing pain.
  • If you get a rash do not put anything on it unless your doctor or nurse says you may. Keep the area around the rash clean and dry. Ask your doctor for medicine if your rash bothers you. 

Food and Drug Interactions

  • This drug may interact with grapefruit and grapefruit juice. Talk to your doctor as this could make side effects worse.
  • This drug may interact with other medicines. Tell your doctor and pharmacist about all the prescription and over-the-counter medicines and dietary supplements (vitamins, minerals, herbs and others) that you are taking at this time. The safety and use of dietary supplements and alternative diets are often not known. Using these might affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's help.
  • Avoid the use of St. John's wort while taking fostamatinib as this may lower the levels of the drug in your body, which can make it less effective. 

When to Call the Doctor

Call your doctor or nurse if you have any of these symptoms and/or any new or unusual symptoms:

  • Fever of 100.5 F (38 C) or higher
  • Chills
  • Fatigue that interferes with your daily activities
  • Feeling dizzy or lightheaded
  • A headache that does not go away
  • Blurry vision or other changes in eyesight
  • Wheezing or trouble breathing
  • Chest pain
  • You cough up yellow, green, or bloody mucus
  • Nausea that stops you from eating or drinking and/or is not relieved by prescribed medicines
  • Loose bowel movements (diarrhea) 4 times a day or loose bowel movements with lack of strength or a feeling of being dizzy
  • Pain that does not go away, or is not relieved by prescribed medicines 
  • A new rash or a rash that is not relieved by prescribed medicines 
  • Signs of possible liver problems: dark urine, pale bowel movements, bad stomach pain, feeling very tired and weak, unusual itching, or yellowing of the eyes or skin
  • If you think you may be pregnant

Reproduction Warnings

  • Pregnancy warning: This drug can have harmful effects on the unborn baby. Women of childbearing potential should use effective methods of birth control during your cancer treatment and for at least 1 month after treatment. Let your doctor know right away if you think you may be pregnant.
  • Breastfeeding warning: Women should not breastfeed during treatment and for at least 1 month after treatment because this drug could enter the breast milk and cause harm to a breastfeeding baby.
  • Fertility warning: Human fertility studies have not been done with this drug. Talk with your doctor or nurse if you plan to have children. Ask for information on sperm or egg banking. 

New April 2018

This patient information was developed by Via Oncology, LLC © 2018. This information is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have.

CLIENT acknowledges that the Via Pathways and Via Portal are information management tools only, and that Via Oncology, LLC has not represented the Via Pathways or Via Portal as having the ability to diagnose disease, prescribe treatment, or perform any other tasks that constitute the practice of medicine. The clinical information contained in the Via Pathways and Via Portal are intended as a supplement to, and not a substitute for, the knowledge, expertise, skill, and judgment of physicians, pharmacists and other healthcare professionals involved with patient care at CLIENT facilities.

This patient information was developed by Via Oncology, LLC © 2018. This information is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have.

CLIENT acknowledges that the Via Pathways and Via Portal are information management tools only, and that Via Oncology, LLC has not represented the Via Pathways or Via Portal as having the ability to diagnose disease, prescribe treatment, or perform any other tasks that constitute the practice of medicine. The clinical information contained in the Via Pathways and Via Portal are intended as a supplement to, and not a substitute for, the knowledge, expertise, skill, and judgment of physicians, pharmacists and other healthcare professionals involved with patient care at CLIENT facilities.