Quizartinib should focus on QT interval prolongation, bone marrow suppression, and drug interaction risks. QT interval prolongation may induce arrhythmia and requires regular electrocardiogram monitoring; Bone marrow suppression manifests as a decrease in blood cells and requires regular blood tests; Drug interactions involve the CYP3A4 enzyme system and should be avoided in combination with potent inducers/inhibitors. The following items detail specific precautions.

1QT interval prolongation

Quetzatinib prolongs the QT interval of the heart and increases the risk of apical torsion to ventricular tachycardia. Before medication, it is necessary to confirm that the baseline QTc is less than 450ms (for males) or 470ms (for females). During the treatment period, monitor the electrocardiogram to steady state every 2 weeks, and then review it monthly. Avoid using other QT prolonging drugs in combination (such as fluoroquinolones).

2. Bone marrow suppression

Common neutropenia, anemia, and thrombocytopenia. Complete blood cell count will be tested weekly in the first month of treatment, followed by monthly monitoring thereafter. If there is grade 3 or above bone marrow suppression, medication should be suspended and reduced before restarting. Febrile neutropenia requires immediate administration of granulocyte colony-stimulating factor.

3 drug interactions

Strong CYP3A4 inhibitors (such as ketoconazole) can increase the blood concentration of quinvatinib by 2 times, and should be avoided in combination or reduced by 50%; Strong inducers (such as rifampicin) can reduce efficacy and should not be used in combination. P-gp substrates (such as digoxin) need to be monitored for toxicity, and it is recommended to adjust the dosage.

4 Special precautions

(1) Patients with liver dysfunction need to reduce their dosage by 30%; Prohibited during pregnancy (animals showing embryotoxicity); Discontinue medication or breastfeeding during lactation. Elderly patients are more prone to QT prolongation and require enhanced monitoring.

(2) Do not freeze or refrigerate, temperatures below 15 ° C may cause the precipitation of drug components. If you need to carry it out, you should use a thermal insulation bag to maintain temperature stability.