Description of the medicine: Calcium folinate (Calcium folinas; Calcium-folinate)

CALCIUM FOLINATE (Calcii folinas; Calcium-folinate).

The calcium salt of folinic acid, or 5-formyl-5,6,7-dihydro-tetrahydrofuric acid, i.e., N- {4 '- [(2-amino-5-formyl-5,6,8,7-tetrahydro -4-hydroxy-pteridyl) methyl] aminobenzoyl} -L-glutamic acid.

Produced in the form of pentahydrate.

Synonyms of folinic acid: Leucovorin, Tsitrovorum factor (The name is due to the fact that folinic acid is a growth factor of the bacteria Leuconostoc citrovorum), Chemifolin, Lederfoline, Rescufolin, Tonofolin, and others.

Yellowish white crystalline powder. Easily soluble in water. Unstable in the light.

By chemical structure and physiological activity is close to folic acid.

Folinic acid is a product of the conversion of folic acid (see) in the body and plays the role of its active metabolite. The conversion of folic acid into folinic acid occurs with the participation of ascorbic acid.

Folinic acid, like folic acid, is effective in megaloblastic and other anemia, sprue, but has no advantages over folic acid. The main medicinal value of folinic acid lies in its antidote activity with respect to the drug (mainly antitumor) drugs, which are antagonists of folic acid. For this purpose, it is used in the form of calcium salt.

The main use of calcium folinate has as an antagonist the side effect of the antitumor drug methotrexate (see).

The antitumor effect of methotrexate (inhibition of the growth of actively proliferating tissues, retardation of growth of malignant tissues) is associated with inhibition of dihydrofolate reductase and blocking the formation of tetrahydrofolate required for DNA biosynthesis. Simultaneously with the antitumor effect, however, oppression of hemopoiesis occurs. Calcium folinate promotes the restoration of folate metabolism, prevents damage to bone marrow cells, protects hemopoiesis and allows the use of methotrexate in high-dose chemotherapy for tumors.

Calcium folinate can be used as an antidote for methotrexate to prevent the possible toxic effects of elevated, high and ultra-high doses, as well as toxic manifestations (ulcerative necrotic stomatitis, enteropathy, etc.) that have developed from the use of conventional methotrexate doses.

Apply calcium folinate intramuscularly or intravenously. Before use, the drug is dissolved in 1 - 2 ml of isotonic sodium chloride solution. The solution is suitable for use for 12 hours when stored in a cool place (not above +8 C).

In the treatment of methotrexate in elevated doses (1 - 5 g) calcium folinate is administered in a single dose of 3 to 10 mg / m 2, at high doses of methotrexate (10-20 g) - in a single dose of 10 to 20 mg / m 2. Initiate injections at 6-18, but no later than 24 hours after methotrexate infusion, then at 6-hour intervals for 48-72 hours. A total of 10-12 doses (from Z0 to 360 mg) are administered for the course of treatment.