Arsil%25252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520dx

# Arsil (Arsenic Trioxide) ## Overview Arsenic trioxide is a naturally occurring inorganic compound used as a potent antineoplastic agent. It induces apoptosis and promotes the degradation of the PML-RARα fusion protein in patients with acute promyelocytic leukemia (APL). ## Primary Indications * First-line treatment of relapsed or refractory acute promyelocytic leukemia (APL). * First-line treatment of newly diagnosed low-to-intermediate risk APL (in combination with all-trans retinoic acid). ## Adult Dosing * **Induction:** 0.15 mg/kg IV daily until bone marrow remission (maximum 60 days). * **Consolidation:** 0.15 mg/kg IV daily for 25 doses over up to 5 weeks. * **Administration:** Infuse IV over 1 to 2 hours. Extend to 4 hours if vasomotor reactions occur. ## Pediatric Dosing * **Ages 5–16 years:** 0.15 mg/kg IV daily. * *Note:* Safety and efficacy in children <5 years are not established. Dosing schedules should follow institutional pediatric oncology protocols (e.g., Children’s Oncology Group). ## Dose Adjustments * **QTc Prolongation:** If QTc >500 msec, withhold treatment. Resume at 50% dose once QTc returns to <460 msec. If QTc remains prolonged, permanent discontinuation may be required. * **Renal/Hepatic Impairment:** No formal dosage adjustments provided in labeling; use with caution. ## Contraindications * Hypersensitivity to arsenic or any component of the formulation. ## Adverse Effects * **Differentiation Syndrome:** Fever, dyspnea, weight gain, pulmonary infiltrates, and pleural/pericardial effusions. May be fatal if untreated. * **Cardiac:** QTc prolongation, Torsades de pointes, ventricular tachycardia. * **Metabolic:** Hyperglycemia, hypokalemia, hypomagnesemia. * **Neurological:** Paresthesia, fatigue. ## Key Drug Interactions * **QT-Prolonging Agents:** Avoid concurrent use with medications known to prolong the QT interval (e.g., ondansetron, fluoroquinolones, azole antifungals). * **Diuretics:** May exacerbate electrolyte imbalances (hypokalemia, hypomagnesemia), further increasing risk of QTc prolongation. ## Monitoring * **Electrocardiogram (ECG):** Baseline and at least twice weekly during induction. * **Electrolytes:** Potassium, magnesium, calcium, and creatinine levels should be maintained in the normal range. * **CBC:** Monitor weekly during induction and consolidation. * **Differentiation Syndrome:** Monitor closely for respiratory distress, weight gain, and unexplained fever. ## Clinical Pearls * **Differentiation Syndrome Prophylaxis:** Often managed with prophylactic dexamethasone (e.g., 10 mg IV BID) upon clinical suspicion. * **Infusion Precautions:** Ensure venous access is secure to prevent extravasation, which may cause tissue irritation. * **Cumulative Toxicity:** Clinicians must be vigilant for secondary malignancies and long-term cardiac monitoring due to the known toxicity profile of arsenic. *** *Disclaimer: This information is for educational purposes only. Dosing and clinical practices vary by institution and patient-specific factors. Always consult the latest FDA-approved prescribing information, institutional guidelines, and clinical databases (e.g., Lexicomp or Micromedex) before prescribing or administering medication.*