Correct usage and recommended dosage of fotantinib/fotantinib

Fostamatinib is an oral tyrosine kinase inhibitor that mainly targets spleen tyrosine kinase (SYK). It is approved overseas for the treatment of chronic immune thrombocytopenia (ITP) and other indications. It modulates the phagocytic activity of macrophages on antibody-coated platelets, thereby reducing platelet destruction and improving patients' platelet levels. The active ingredient of fostamatinib is R406, and fostamatinib itself is a prodrug, which is metabolized into its active form through the intestinal tract in the body. The correct way of taking medication is of decisive significance to ensure the efficacy of the drug and avoid adverse reactions.

Usually fotantinib is taken orally in the form of tablets, and each dose and frequency of use are determined based on the patient's underlying condition and tolerance to the drug. The recommended starting dose is usually 100 mg twice a day, which can be taken before or after meals. However, it is recommended to take the drug at the same time every day to maintain stable blood concentration. If the initial dose fails to maintain an adequate clinical response and the drug is well tolerated by the patient, physicians may consider increasing the dose to 150 mg twice daily, which is currently the maximum dose commonly seen clinically. It is worth noting that before increasing the dose, it is necessary to monitor platelet levels and evaluate liver and kidney function through blood routine to avoid increased toxicity due to drug accumulation.

Since fotantinib may affect blood pressure, liver function and blood aminotransferase levels, regular biochemical monitoring is required during treatment. For patients who experience adverse reactions during medication, such as hypertension, elevated liver enzymes, or diarrhea, temporary dose reduction, suspension, or termination of treatment should be considered based on the severity. Patients should avoid concurrent use of strong CYP3A4 inducers or inhibitors while taking this drug, as these drugs may affect the metabolism rate of R406, thus interfering with efficacy or increasing toxicity. In addition, antacids such as aluminum or magnesium drugs may interfere with their absorption, so it is recommended to take them at least 2 hours apart.

Reference materials:https://go.drugbank.com/drugs/DB12010