Cytosar NovaMedica, lyophilizate 500 mg

Pharmacotherapeutic group: antitumor drug, antimetabolite.

ATC code: L01BC01

Pharmacological properties

Pharmacodynamics.

Citarabine belongs to the group of pyrimidine metabolites and is an S-phase-specific drug. It inhibits DNA synthesis in the cell. The drug acquires antileukemic activity as a result of phosphorylation into arabinosyl cytosine triphosphate (Ara-CTP), which competitively inhibits DNA polymerase. In addition, there is evidence that DNA synthesis is also inhibited by the incorporation of cytarabine into DNA and RNA.Several mechanisms for the development of resistance to cytarabine are known: inhibition of membrane transport, deficiency of

phosphorylation enzymes, increased activity of inactivating enzymes, reduced affinity for DNA polymerase or increased pool of deoxy-CTF. Cytotoxic action is achieved by creating constant high intracellular concentrations of Ara-CTF.

Pharmacokinetics.

After intravenous administration, cytarabine is rapidly and almost completely converted to the inactive uracil metabolite Ara-U under the action of cytidine deaminase in the liver and other tissues. The half-life in the initial phase is 10 minutes, in the final phase – about 1-3 hours. Since deaminase activity in the CNS is minimal, excretion of cytarabine from cerebrospinal fluid is slow, with a half-life of 2-11 hours.

Continuous intravenous infusions of cytarabine at normal doses (100-200 mg/m2 body surface) achieve concentrations equal to 0.04-0.6 μmol/L. When administered subcutaneously (p/k), maximum plasma concentrations are reached within 20-60 minutes. Then there is a biphasic decrease in concentration. A small part of cytarabine undergoes phosphorylation under the influence of kinases at the intracellular level, as a result of which the active metabolite Ara-CTP is formed. The binding to plasma proteins is 15%.

Citarabine penetrates the blood-brain barrier. After continuous infusion, a concentration equal to 10-40% of the plasma concentration is reached in the cerebrospinal fluid. After administration of normal or high doses, only 4-10% of the administered dose is excreted unchanged by the kidneys. In the first 24 hours, 71-96% of the administered drug is detected in the urine in the form of Ara-U.

Indications

Active ingredient

Composition

How to take, the dosage

Interaction

Special Instructions

Contraindications

With caution: hepatic and/or renal insufficiency (due to increased risk of neurotoxicity, especially during high-dose therapy), drug-induced suppression of hematopoiesis, bone marrow infiltration by tumor cells, acute infectious diseases of viral (including varicella, chicken pox and lepox).varicella, shingles), fungal or bacterial diseases (risk of severe complications and generalization), diseases with increased risk of hyperuricemia (gout or urate nephrolithiasis).

Side effects

Overdose