). Death has been reported when folinic acid has been administered intrathecally following intrathecal overdose of methotrexate. • Leucovorin Calcium Injection USP should only be used with 5-fluorouracil or methotrexate under the direct supervision of a clinician experienced in the use of cancer chemotherapeutic agents.
• Patients receiving any combination therapy regimen involving leucovorin and fluorouracil should be carefully monitored for diarrhea and/or stomatitis/mucositis as these are the first indications that severe and potentially life-threatening toxicity could develop (see 7 WARNINGS AND PRECAUTIONS and 9 DRUG INTERACTIONS).
• Fatalities have occurred as a result of gastrointestinal toxicity (predominantly mucositis and diarrhea) (see 7 WARNINGS AND PRECAUTIONS and 8 ADVERSE REACTIONS). • Fatalities have occurred as a result of myelosuppression (see 7 WARNINGS AND PRECAUTIONS and 8 ADVERSE REACTIONS).
• Cases of Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), some fatal, have been reported in patients receiving leucovorin in combination therapy (see 8 ADVERSE REACTIONS). • Leucovorin may diminish the effect of anti-epileptic substances such as phenobarbital, primidone and phenytoin.
During leucovorin administration in epileptic patients treated with these substances, there is a risk to increase the frequency of seizures due to a decrease of plasma concentrations of anti-epileptic drugs (see 9 DRUG INTERACTIONS).
2 Recommended Dose and Dosage Adjustment Due to calcium content of leucovorin solution, no more than 160 mg of leucovorin should be injected, per minute, intravenously.
Treatment of Overdosage of Folic Acid Antagonists:
In cases of overdosage of folic acid antagonists, prompt administration of leucovorin calcium is essential; if a period of more than four hours intervenes, the treatment may be ineffective. The dose of leucovorin calcium should be equal to or greater than the suspected dose of folic acid antagonist.
Where large doses of methotrexate have been given, leucovorin may be administered by intravenous infusion in doses up to 75 mg within 12 hours, followed by 12 mg intramuscularly every six hours, for four doses. In less severe overdosage, 6 to 12 mg of leucovorin may be given intramuscularly every six PrLeucovorin Calcium Injection USP - Product Monograph Page 6 of 22 hours, for four doses, until the serum methotrexate level is less than 10-8M.
Use After Chemotherapy with Methotrexate:
The dosage and scheduling of doses of leucovorin varies, but it is normally given about 6 to 24 hours following methotrexate administration, in amounts equal to the weight of methotrexate given. Serum creatinine and methotrexate levels should be determined at 24-hour intervals.
If the 24-hour serum creatinine has increased 50% over baseline or if the 24-hour methotrexate level is greater than 5 x 10-6M or the 48-hour level is greater than 9 x 10-7M, the dose of leucovorin should be increased to 100 mg/m2 intravenously every 3 hours until the methotrexate level is less than 10-8M.
Hydration (3 L/day) and urinary alkalinization with NaHCO3 should be employed concomitantly. 0 or greater. In most cases, leucovorin should not be administered simultaneously with systemic methotrexate, since the therapeutic effect of the antimetabolite may be nullified.
However, when methotrexate is administered by intra-arterial (regional perfusion) or intrathecal injection, leucovorin may be given (intramuscularly, intravenously or orally) concomitantly, to offset systemic methotrexate toxicity without abolishing the local activity of the cytotoxic drug.
Treatment of Megaloblastic Anemia:
For treatment of megaloblastic anemia due to folate deficiency, the dose should not exceed 1 mg daily. The duration of therapy depends on the hematologic response to the drug. Oral leucovorin is preferred to parenteral therapy, except where cases of severe vomiting impair drug absorption when administered orally.
Treatment of Advanced Colorectal Cancer:
Leucovorin is administered at 200 mg/m2 by slow intravenous injection prior to dosing with 370 mg/m2 fluorouracil by slow intravenous injection, for 5 consecutive days. This 5-day treatment course may be repeated at 4-week (28 days) intervals, provided that the patient has completely recovered from the toxic effects of the prior treatment course.
In subsequent treatment courses, the dosage of fluorouracil should be adjusted based on patient tolerance of the prior treatment course. The daily dosage of fluorouracil should be reduced by 20% for patients who experienced moderate hematologic or gastrointestinal toxicity in the prior treatment course, and by 30% for patients who experienced severe toxicity.
For patients who did not experience toxicity in the prior treatment course, fluorouracil dosage may be increased by 10%. Leucovorin dosages are not adjusted for toxicity. 05 mg/mL leucovorin. These dilutions may be stored for 24 hours at room temperature.
Due to the possibility of antimicrobial contamination, PrLeucovorin Calcium Injection USP - Product Monograph Page 7 of 22 unused solution should be discarded after that time. 05 mg/mL of leucovorin. However, these dilutions should be stored for no longer than 8 hours at room temperatures.
Unused solution should be discarded after that time. All steps of dilution must be done in non-PVC materials.. 4 Administration […]