Overview
11 DESCRIPTION Levoleucovorin is a folate analog and the pharmacologically active levo-isomer of d,l -leucovorin. The chemical name of levoleucovorin calcium is calcium (6 S )-N-{4-[[(2-amino-5-formyl-1,4,5,6,7,8-hexahydro-4-oxo-6-pteridinyl)methyl] amino]benzoyl}- L -glutamate mixed hydrates. The molecular formula is C 20 H 21 CaN 7 O 7 ● nH 2 O (n = 3 to 6) and the molecular weight is 565.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action High-Dose Methotrexate Therapy Levoleucovorin is the pharmacologically active isomer of 5-formyl tetrahydrofolic acid. Levoleucovorin does not require reduction by the enzyme dihydrofolate reductase in order to participate in reactions utilizing folates as a source of “one-carbon” moieties. Administration of levoleucovorin counteracts the therapeutic and toxic effects of folic acid antagonists such as methotrexate, which act by inhibiting dihydrofolate reductase. Combination with Fluorouracil in Colorectal Cancer Levoleucovorin enhances the therapeutic and toxic effects of fluorouracil.
Indications
- 1 INDICATIONS AND USAGE Levoleucovorin Injection is indicated for: rescue after high-dose methotrexate therapy in adult and pediatric patients with osteosarcoma. diminishing the toxicity associated with overdosage of folic acid antagonists or impaired methotrexate elimination in adult and pediatric patients. the treatment of adults with metastatic colorectal cancer in combination with fluorouracil. Limitations of Use Levoleucovorin Injection is not indicated for pernicious anemia and megaloblastic anemia secondary to the lack of vitamin B 12 , because of the risk of progression of neurologic...
Common Doses
- 7.5 mg
- 5 mg
- 100 mg
- 370 mg
Dosage
2 DOSAGE AND ADMINISTRATION For intravenous administration only. Do not administer intrathecally. ( 2.1 ) Rescue After High-Dose Methotrexate Therapy Rescue recommendations are based on methotrexate dose of 12 grams/m 2 administered by intravenous infusion over 4 hours. Initiate rescue at a dose of 7.5 mg (approximately 5 mg/m 2 ) every 6 hours, 24 hours after the beginning of methotrexate infusion. ( 2.3 ) Continue until the methotrexate level is below 5 x 10 -8 M (0.05 micromolar). Adjust dose if necessary based on methotrexate elimination; refer to Full Prescribing Information. ( 2.
Contraindications
- 4 CONTRAINDICATIONS Levoleucovorin is contraindicated in patients who have had severe hypersensitivity to leucovorin products, folic acid or folinic acid [see Adverse Reactions ( 6.2 )] . Patients who have had severe hypersensitivity reactions to leucovorin products, folic acid or folinic acid. ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Hypercalcemia [see Warnings and Precautions ( 5.1 )] Increased gastrointestinal toxicities with fluorouracil [see Warnings and Precautions ( 5.2 )] The most common adverse reactions (≥20%) in patients receiving high-dose methotrexate therapy with levoleucovorin rescue are stomatitis and vomiting. ( 6.1 ) The most common adverse reactions (>50%) in patients receiving levoleucovorin in combination with fluorouracil for metastatic colorectal cancer are stomatitis, diarrhea, and...
Interactions
- 7 DRUG INTERACTIONS 7.1 Effects of Leucovorin Products on Other Drugs Antiepileptic Drugs Folic acid in large amounts may counteract the antiepileptic effect of phenobarbital, phenytoin and primidone and increase the frequency of seizures in susceptible children. It is not known whether folinic acid has the same effects; however, both folic and folinic acids share some common metabolic pathways. Monitor patients taking folinic acid in combination with antiepileptic drugs. Fluorouracil Leucovorin products increase the toxicity of fluorouracil.