Fostamatinib

How it works

Its active metabolite inhibits SYK, reducing antibody-mediated destruction of platelets by macrophages and thereby raising the platelet count.

Prescribing in practice

• It can cause hypertension, so blood pressure must be monitored and managed during treatment.
• Diarrhoea, hepatotoxicity and neutropenia can occur and may require dose modification.
• It interacts with strong CYP3A4 inhibitors and inducers and with certain other substrates, so co-medication should be reviewed.

Monitoring

Monitor platelet count, blood pressure, liver function and neutrophil count regularly throughout treatment.

Counselling the patient

• Attend appointments for blood pressure and blood test monitoring.
• Report severe or persistent diarrhoea, or signs of infection or jaundice.
• Tell your team about all other medicines, as interactions are important.

Evidence & guidelines

Fostamatinib is recommended for chronic immune thrombocytopenia refractory to other treatments, supported by its licensed indication and NICE appraisal.