arsenic trioxide: clinical use

Prescribing considerations

• Restrict initiation and administration to clinicians experienced in acute leukaemia management.
• Assess concurrent medicines and correct electrolyte abnormalities before treatment.
• Use caution in renal or hepatic impairment because evidence is limited; dialysis use has not been studied.
• Older adults and clinically unstable patients may require closer observation.
• Remain alert for differentiation syndrome, hyperleucocytosis, hepatotoxicity, neuropathy and encephalopathy.

Contraindications and cautions

• Hypersensitivity to arsenic trioxide or any excipient.

Monitoring

• Baseline and serial 12-lead ECG, with continuous monitoring where cardiac risk is increased.
• Potassium, calcium, magnesium and creatinine; correct abnormalities promptly.
• Full blood count and assessment for rising leucocyte count or differentiation syndrome.
• Glucose, liver and renal function, and coagulation parameters.
• More frequent clinical and laboratory review for unstable patients.

Clinical pharmacology

In solution, arsenic trioxide forms pharmacologically active trivalent arsenic. It distributes widely into tissues, undergoes oxidation and hepatic methylation, and is eliminated mainly through urine as unchanged arsenic and methylated metabolites. It does not appear to inhibit the major cytochrome P450 enzymes in vitro.

Formulation and product differences

• Clear, colourless, sterile concentrate for intravenous infusion.
• Contains no preservative, is for single use and requires aseptic dilution in compatible glucose or sodium chloride solution.
• Essentially sodium-free and must not share an intravenous line with other medicines.

Solution for infusion

Route: Intravenous

Strengths: 1 mg/mL, 2 mg/mL