Enruining Dexrazoxane for Injection

1. Indications and Usage
Cardioprotection in Breast Cancer:
Indicated for use in patients with metastatic breast cancer who have received a cumulative doxorubicin dose of 300 mg/m² and who require continued doxorubicin-containing chemotherapy to maintain tumor control.
Treatment of Extravasation:
Indicated for the treatment of patients with anthracycline extravasation.
2. Dosage and Administration
Cardioprotection Dosage:
Ratio: Administered at a molar ratio of 10:1 (Dexrazoxane:Doxorubicin).
Dose: 500 mg/m² (if Doxorubicin is 50 mg/m²).
Timing: Administered within 30 minutes before the doxorubicin infusion.
Extravasation Dosage:
Dose: 1000 mg/m² on Day 1 and Day 2, followed by 500 mg/m² on Day 3.
Timing: Initiate as soon as possible after extravasation is identified.
3. Mechanism of Action
Iron Chelation:
Dexrazoxane is a cell-permeable cyclic derivative of ethylenediaminetetraacetic acid (EDTA).
Physiological Effect:
It is converted intracellularly to a ring-opened form that binds to intracellular iron (Fe³⁺), preventing the formation of iron-anthracycline complexes and the subsequent generation of free radicals that cause cardiomyocyte damage.
4. Safety and Warnings
Bone Marrow Suppression:
Dexrazoxane can exacerbate myelosuppression caused by chemotherapy. Monitor complete blood counts (CBC) frequently.
Antitumor Activity:
There is evidence that dexrazoxane may affect antitumor activity if used from the very first cycle of doxorubicin therapy.
5. Adverse Reactions
Most Common:
Leukopenia, neutropenia, thrombocytopenia, anemia, and pain at the injection site.
Secondary Malignancies:
Secondary malignancies (e.g., acute myeloid leukemia) have been reported with long-term use of related racemic mixtures.
6. Drug Interactions
Chemotherapy Agents:
Dexrazoxane does not significantly alter the pharmacokinetics of doxorubicin but may increase the toxicity of concomitant chemotherapy.
7. Pharmaceutical Information
Chemical Composition:
Active Ingredient: Dexrazoxane.
Storage:
Store at controlled room temperature. Reconstitute with Sodium Lactate Injection (0.167 mol/L).