Treatment of toxic plasma methotrexate (MTX) concentrations (>1 micromole per liter) in patients with delayed MTX clearance due to impaired renal function.
<1 month: not recommended. ≥1 month: Give as bolus IV inj over 5 minutes. 50Units/kg as a single injection. Continue leucovorin therapy until the MTX concentration is below the leucovorin treatment threshold for at least 3 days. Do not administer leucovorin within 2hrs before or after a dose of glucarpidase. First 48hrs after glucarpidase: administer same leucovorin dose as given prior to glucarpidase. Beyond 48hrs after glucarpidase: give leucovorin dose based on the measured MTX concentration.
Not indicated for use in patients who exhibit the expected clearance of MTX (plasma MTX concentrations within 2 standard deviations of the mean MTX excretion curve specific for the dose of MTX administered) or those with normal or mildly impaired renal function. Monitor MTX concentrations only by chromatographic methods within 48hrs following administration. Continue hydration and alkalinization of urine as indicated. Pregnancy (Cat. C). Nursing mothers.
See Adults and children. Other exogenous substrates including reduced folates and folate antimetabolites may cause interference.
Paresthesia, flushing, nausea, vomiting, hypotension, headache; rare: allergic reactions, antibody formation.