Treatment for Methotrexate Overdose

Initial Management

In the event of a methotrexate overdose, early treatment with leucovorin (folinic acid) is life-saving and should be administered as promptly as possible, along with supportive measures including hydration and urinary alkalinization, as recommended by the British Journal of Dermatology 1, 2, 3
If the overdose occurred within 1 hour and is ≥1 mg/kg, administer activated charcoal to reduce absorption, according to the British Journal of Dermatology 1, 3
Admit the patient to hospital immediately and measure serum methotrexate levels at least 4 hours after ingestion, as suggested by the British Journal of Dermatology 1, 2, 3
Initial leucovorin dose should be up to 100 mg/m² by intravenous infusion if methotrexate level is unknown, as recommended by the British Journal of Dermatology 1, 3
Continue leucovorin with subsequent oral/intravenous doses every 6 hours based on methotrexate levels, according to the British Journal of Dermatology 1, 3

Maintain aggressive hydration to improve renal elimination of methotrexate, as suggested by the British Journal of Dermatology 1, 3
Perform urine alkalinization with sodium bicarbonate to prevent methotrexate precipitation in renal tubules, according to the British Journal of Dermatology 1, 3
Monitor complete blood count, liver function, and renal function regularly, as recommended by Praxis Medical Insights 4
Continue leucovorin until methotrexate levels are <0.05 μmol/L or until hematological abnormalities and mucosal ulceration have resolved, as suggested by the British Journal of Dermatology 1, 3

For bone marrow suppression: administer filgrastim (granulocyte colony-stimulating factor) subcutaneously at 5 μg/kg daily to accelerate myeloid recovery, according to the British Journal of Dermatology 1, 3

Monitor for mucositis, fever, diarrhea, erythema, and ulceration, which may take 6-23 days to manifest, as suggested by the British Journal of Dermatology 1, 3
Do not underestimate the severity of methotrexate overdose - there is high mortality risk even with appropriate treatment, as warned by the British Journal of Dermatology 1, 3

Do not delay leucovorin administration while waiting for methotrexate levels - early treatment is critical, as emphasized by the British Journal of Dermatology 1
Do not underestimate the severity of methotrexate overdose - there is high mortality risk even with appropriate treatment, as warned by the British Journal of Dermatology 1, 3