CYTOSARUM (Cytosar; synonym: Alexan, Ara-C, Aracytidine, Cytarabine, Cyto-sinarabinosid, etc.; joint venture. A) — antineoplastic means; treats group of antimetabolites of a synthetic origin. l ~ | 3-D-Apa-binofuranoziltsitozin:
C. let's dissolve in water, isotonic solution of sodium chloride, solution of glucose, the phosphatic buffer, 0,9% solution of benzyl alcohol; it is hygroscopic.
Cytostatic action of C. it is connected with its turning into 5-mono-fosfatnukleotid, a cut it is catalyzed by deoksitsitidinkinazy. Nucleotides of C. block polymerases (a DNA polymerase and a RNA-dependent DNA polymerase of oncornaviruses) and join in chains of RNA and DNA. Are most sensitive to C. the cells which are in a S-phase of a mitosis (see). In the cells having low activity of a deoksitsitidinkinaza or high activity of a tsitidindeamina-za, C. it is not activated. Metabolism of C. occurs very quickly — in
5 — 15 min. after single intravenous administration in a high dose. At introduction to spinal channel C. it is deaminized more slowly. In the conditions of long intravenous infusion concentration of C. in blood constantly remains on a high level. In a liver and, perhaps, in kidneys of C. it is deaminized with formation of an inactive metabolite of macaw-binofuranoziluratsila, to-ry it is removed generally with urine during 14 — 24 hours after administration of drug. At intravenous use of 5 — 8% of Cytosarum it is removed in not changed look.
Use of C. it is shown at acute leukoses (the SI.) all types, blast crisis hron. a myeloid leukosis, lymphosarcomas (see L of an imfosar-lump) and a reticulosarcoma (see). Besides, C. in small doses apply to treatment of shingles (see Herpes). As independent remedy at leukoses and gematosarkoma of C. it is ineffective: frequency of remissions does not exceed 25%, from them full no more than 10%. Therefore drug is appointed in a complex with other antineoplastic means, preferential antineoplastic antibiotics (rubomitsin, Adriablastinum); frequency of remissions at the same time increases up to 70 — 80%, from them full more than 50%. C. enter intravenously, subcutaneously and at treatment of neuroleukaemia (see Leukoses) into the spinal canal. For induction of remission of C. apply intravenously by long infusion during 3 — 7, 10 days, in a dose of 2 — 3 mg/kg are more rare. For the supporting treatment of C. appoint subcutaneously, at the same time divide a daily dose into 3 — 4 introductions. Treatment is carried out in a hospital.
The main and most frequent side effect — oppression of a marrowy hemopoiesis, a cut comes to light both in the course of treatment, and 7 — 10 days later and promotes emergence of infectious and hemorrhagic complications. Besides, nausea, vomiting, a diarrhea, an abnormal liver function, thrombophlebitis can be observed.
A contraindication to treatment of C. oppression of a marrowy hemopoiesis is.
Form of release: in the lyophilized look on 100 and 500 mg in bottles. Just before the use contents of a bottle are dissolved in 10 ml of the enclosed solvent. Store in the cold dark place.
Bibliography: B of l about x and N of H. N and Pere -
vodchikovan. I. Himioterapiya of tumoral diseases, M., 1984;
R u d-n i with k S. And. and. lake of High dose cytosine ara-binoside (HDARAC) of in refractory acute leukemia, Cancer, v. 44, p. 1189, 1979; Yates J. o. Cytosine arabinoside with daunorubicin or adriamycin for therapy of acute myelocytic leukemia, Blood, v. 60, p. 454, 1982. G. V. Kruglova.