1Stop leucovorin because continued folate rescue will prevent methotrexate from leaving the bloodstream.
2Continue leucovorin, IV hydration, and bicarbonate to urine pH 7 or higher while trending methotrexate and creatinine.✓ Correct answer
3Reduce the IV fluid rate because hydration delays methotrexate clearance when creatinine is elevated.
4Give activated charcoal and acidify the urine to increase renal elimination of methotrexate.
Explanation
Delayed methotrexate elimination and rising creatinine increase the risk of severe toxicity. Leucovorin rescue, hydration, and urinary alkalinization should continue, with urine pH maintained at 7 or higher and serum methotrexate and creatinine monitored at least daily. Rescue dose and duration are adjusted to laboratory results. Urine acidification increases methotrexate precipitation risk, and activated charcoal is not a substitute for the prescribed rescue plan.
Clinical reasoning Methotrexate and its metabolites are less soluble in acidic urine. Kidney injury slows elimination, so hydration and alkalinization protect renal clearance while leucovorin rescues healthy cells from folate antagonism.
Decision rule For delayed high-dose methotrexate clearance, continue leucovorin, hydration, and urine alkalinization; trend drug level, creatinine, urine output, pH, and electrolytes.
Scenario A client receiving high-dose methotrexate has a persistently elevated methotrexate concentration, increasing creatinine, and urine pH of 6.5. Scheduled leucovorin rescue is in progress.
Leucovorin rescue — Folinic acid therapy used after high-dose methotrexate to reduce toxicity in normal tissues.
Urinary alkalinization — Use of bicarbonate to maintain urine pH at 7 or higher and reduce methotrexate precipitation in renal tubules.
Glucarpidase — Enzyme rescue for delayed MTX clearance with AKI; used in toxic levels.