Drug Interaction Report

MONITOR: The concomitant use of bone marrow depressants and sodium phosphate P-32 may have additive myelosuppressive effects.

MANAGEMENT: Patients should be monitored for excessive bone marrow suppression during treatment with sodium phosphate P-32. Sodium phosphate P-32 should not be used as part of a sequential treatment with a chemotherapeutic agent. Dose reductions of the other bone marrow depressants may be necessary. The manufacturer's labeling should be consulted for more specific recommendations for each agent involved. Patients should be advised to contact their physician if they develop signs and symptoms of myelosuppression such as pallor, dizziness, fatigue, lethargy, fainting, easy bruising or bleeding, or signs of infection such as fever, chills, sore throat, body aches, and other influenza-like symptoms.

ADJUST DOSING INTERVAL: Administration of trifluridine-tipiracil with a standardized high-fat, high-calorie meal has been shown to decrease trifluridine peak plasma concentration (Cmax) as well as tipiracil Cmax and systemic exposure (AUC) by approximately 40% compared to administration in a fasting state in patients with cancer given a single 35 mg/m2 dose. No change in trifluridine AUC was observed.

MANAGEMENT: Based on the observed correlation between increases in the Cmax of trifluridine and decreases in neutrophil counts, trifluridine-tipiracil should be taken within one hour after completion of the morning and evening meals.