Quizartinib is a selective FLT3 kinase inhibitor indicated for the treatment of adult patients with newly diagnosed FLT3-ITD positive acute myeloid leukemia (AML). When used in combination with standard chemotherapy regimens, this drug plays a crucial role in the induction, consolidation, and maintenance phases of treatment.

What are the precautions for taking Quizartinib?

1. Patient Selection

(1) The presence of FLT3-ITD mutation in patients must be confirmed using a test method approved by the FDA before administration.

(2) Before treatment, the following contraindications should be excluded: severe hypokalemia, severe hypomagnesemia, long QT syndrome, and a history of ventricular arrhythmias or torsades de pointes.

2. Risk Assessment

(1) Electrocardiogram (ECG) Monitoring

An ECG must be performed before medication administration to confirm that the QTcF interval is ≤ 450 ms.

(2) Electrolyte Balance

Correct any existing hypokalemia and hypomagnesemia.

(3) Concomitant Medication Review

Avoid concurrent use of other drugs that prolong the QT interval.

3. Administration Precautions

(1) Take the medication at a fixed time daily, either with food or on an empty stomach.

(2) Swallow the tablet whole; do not cut, crush, or chew it.

(3) If vomiting occurs after taking the medication, do not take an additional dose. Wait for the next scheduled dose.

4. Administration in Special Populations

(1) Patients with Hepatic Impairment

No dose adjustment is required for patients with mild to moderate hepatic impairment.

Data on the use of this drug in patients with severe hepatic impairment are limited, so administration should be done with caution.

(2) Patients with Renal Impairment

No dose adjustment is required for patients with mild to moderate renal impairment (creatinine clearance 30-89 mL/min).

The safety of this drug in patients with severe renal impairment (creatinine clearance < 30 mL/min) has not been established.

5. Drug Interactions

(1) Strong CYP3A Inhibitors (e.g., Ketoconazole)

The dose of quizartinib needs to be reduced.

(2) Strong or Moderate CYP3A Inducers (e.g., Efavirenz)

Concurrent use should be avoided.

(3) Drugs that Prolong the QT Interval

If concurrent use is necessary, enhanced ECG monitoring is required.

6. Medication Monitoring for Quizartinib

(1) Requirements for ECG Monitoring

Baseline: Must be completed before the start of treatment.

Induction and Consolidation Phases: Once a week.

Initial Maintenance Treatment Phase: At least once a week for the first month after the dose is initiated and increased.

(2) Electrolyte Monitoring

Regularly monitor serum potassium and magnesium levels to maintain electrolytes within the normal range.

Pay special attention to patients with diarrhea or vomiting, and increase the frequency of monitoring for such patients.

(3) Hematological Monitoring

Focus on monitoring neutrophil and platelet counts.

When grade 4 neutropenia or thrombocytopenia occurs after achieving remission, the dose needs to be reduced.

Bone marrow evaluation is recommended to confirm the cause of cytopenia.