Tavafos

Indications

Fostamatinib is used to treat adults with chronic immune thrombocytopenia (ITP), a condition in which the immune system destroys platelets (the blood cells that help clotting), when earlier treatments have not worked well enough. It aims to raise the platelet count and lower the risk of bleeding.

How It Works

Fostamatinib is a prodrug that is changed in the gut into its active form, which blocks an enzyme called spleen tyrosine kinase (SYK). SYK helps immune cells in the spleen and liver grab and destroy antibody-coated platelets. By blocking it, fewer platelets are destroyed and the platelet count can rise.

Dosage and Administration

Take exactly as prescribed by your doctor. Treatment is usually started at 100 mg twice a day by mouth, and the doctor may increase the dose depending on the platelet count. Tablets can be taken with or without food and should be swallowed whole. Your doctor will check blood counts, liver tests and blood pressure regularly and may lower the dose, pause or stop treatment.

Interactions

• Strong CYP3A4 inhibitors such as Ketoconazole or Clarithromycin may raise Fostamatinib levels and side effects.
• Strong CYP3A4 inducers such as Rifampicin, Carbamazepine or Phenytoin may make it less effective.
• It can raise the levels of Rosuvastatin, Simvastatin and Digoxin; dose checks may be needed.

Tell your doctor about all medicines, herbal products and supplements you take.

Contraindications

Do not use if you are allergic to Fostamatinib or any ingredient of the tablet, or if you are pregnant.

Side Effects

Common side effects include diarrhoea, raised blood pressure, nausea, dizziness, raised liver enzymes, rash, stomach pain, tiredness, chest pain and a low white blood cell count (neutropenia), which can increase the risk of infection.

Get urgent medical help if you have very high blood pressure with severe headache or chest pain, yellowing of the skin or eyes, dark urine, severe or persistent diarrhoea, fever or signs of a serious infection, or signs of an allergic reaction.

Pregnancy and Lactation

Fostamatinib can harm an unborn baby. Women who could become pregnant should use effective contraception during treatment and for at least 1 month after the last dose. Do not breastfeed during treatment and for at least 1 month after the last dose.

Precautions and Warnings

• Blood pressure should be checked regularly; existing high blood pressure should be controlled.
• Liver tests are checked monthly at first.
• Diarrhoea is common: drink fluids and tell your doctor if it is severe.
• Blood counts are checked to watch for neutropenia.

Overdose

There is no specific antidote. An overdose may make side effects such as diarrhoea, high blood pressure or liver problems worse. Contact a doctor or the nearest hospital straight away.

Therapeutic Class

Spleen tyrosine kinase (SYK) inhibitor; treatment for chronic immune thrombocytopenia.

Storage

Store below 30°C in a dry place, away from light, in the original container, and out of the reach of children.