Fostamatinib/Strong CYP3A4 Inhibitors Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Some medicines may slow down (inhibit) how quickly your liver processes fostamatinib.

What might happen:

The amount of fostamatinib in your blood may increase and cause more side effects than normal, including high blood pressure, liver problems, severe diarrhea, and increased risk of infections.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Your doctor may want to change the dose of your fostamatinib while you are taking your other medicine.Let your doctor know right away if you have chest pain, shortness of breath, confusion, dizziness, or abdominal pain.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Tavalisse (fostamatinib) prescribing information. Rigel Pharmaceuticals, Inc April 2018.
  • 2.Tavlesse (fostamatinib) UK summary of product characteristics. Grifols UK Ltd June 4, 2020.
  • 3.Martin P, Gillen M, Millson D, Oliver S, Brealey C, Grossbard EB, Baluom M, Lau D, Sweeny D, Mant T, Craven K. Effects of CYP3A4 Inhibitors Ketoconazole and Verapamil and the CYP3A4 Inducer Rifampicin on the Pharmacokinetic Parameters of Fostamatinib: Results from In Vitro and Phase I Clinical Studies. Drugs R D 2016 Mar;16(1):81-92.
  • 4.This information is based on or an extract from the UW Metabolism and Transport Drug Interaction Database (DIDB) Platform, Copyright University of Washington 1999-2019..

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.