Clinical data | |
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Trade names | Cytosar-U, Depocyt, others |
AHFS/Drugs.com | Monograph |
MedlinePlus | a682222 |
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Routes of administration | injectable (intravenous injection or infusion, intrathecal, or subcutaneously) |
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Pharmacokinetic data | |
Bioavailability | 20% by mouth |
Protein binding | 13% |
Metabolism | Liver |
Elimination half-life | biphasic: 10 min, 1–3 hr |
Excretion | Kidney |
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ChemSpider | |
UNII | |
KEGG | |
ChEBI | |
ChEMBL | |
PDB ligand | |
CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.005.188 |
Chemical and physical data | |
Formula | C9H13N3O5 |
Molar mass | 243.219 g·mol−1 |
3D model (JSmol) | |
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Cytarabine, also known as cytosine arabinoside (ara-C), is a chemotherapy medication used to treat acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), chronic myelogenous leukemia (CML), and non-Hodgkin's lymphoma. [2] It is given by injection into a vein, under the skin, or into the cerebrospinal fluid. [2] There is a liposomal formulation for which there is tentative evidence of better outcomes in lymphoma involving the meninges. [2]
Common side effects include bone marrow suppression, vomiting, diarrhea, liver problems, rash, ulcer formation in the mouth, and bleeding. [2] Other serious side effects include loss of consciousness, lung disease, and allergic reactions. [2] Use during pregnancy may harm the baby. [2] Cytarabine is in the antimetabolite and nucleoside analog families of medication. [3] It works by blocking the function of DNA polymerase. [2]
Cytarabine was patented in 1960 and approved for medical use in 1969. [4] It is on the World Health Organization's List of Essential Medicines. [5]
Cytarabine is mainly used in the treatment of acute myeloid leukaemia, acute lymphocytic leukaemia (ALL) and in lymphomas, [6] where it is the backbone of induction chemotherapy.
Cytarabine also possesses antiviral activity, and it has been used for the treatment of generalised herpesvirus infection. However, cytarabine is not very selective in this setting and causes bone marrow suppression and other severe side effects. Therefore, ara-C is not a useful antiviral agent in humans because of its toxic profile. [7]
Cytarabine is also used in the study of the nervous system to control the proliferation of glial cells in cultures, the amount of glial cells having an important impact on neurons.[ citation needed ] Recently, cytarabine was reported to promote robust and persistent neuronal differentiation in NSC-34 motor neuron-like cell line. Cytarabine is permissive, dispensable, and mostly irreversible in priming NSC-34 cells for neurite initiation and regeneration after mechanical dislodgement. [8]
One of the unique toxicities of cytarabine is cerebellar toxicity when given in high doses, which may lead to ataxia. Cytarabine may cause granulocytopenia and other impaired body defenses, which may lead to infection, and thrombocytopenia, which may lead to hemorrhage.[ citation needed ]
Toxicity: pancreatitis, leukopenia, thrombocytopenia, anemia, GI disturbances, stomatitis, conjunctivitis, pneumonitis, fever, and dermatitis, palmar-plantar erythrodysesthesia. Rarely, myelopathy has been reported after high dose or frequent intrathecal Ara-C administration. [9]
When used in protocols designated as high dose, cytarabine can cause cerebral and cerebellar dysfunction, ocular toxicity, pulmonary toxicity, severe GI ulceration and peripheral neuropathy (rare).[ citation needed ]
To prevent the side effects and improve the therapeutic efficiency, various derivatives of these drugs (including amino acid, peptide, fatty acid and phosphates) have been evaluated, as well as different delivery systems. [10]
Cytosine arabinoside combines a cytosine base with an arabinose sugar. It is an antimetabolic agent with the chemical name of 1β-arabinofuranosylcytosine. Certain sponges, where similar compounds were originally found, use arabinoside sugars for chemical defense. [11] Cytosine arabinoside is similar enough to human deoxycytosine to be incorporated into human DNA, but different enough that it kills the cell. Cytosine arabinoside interferes with the synthesis of DNA. Its mode of action is due to its rapid conversion into cytosine arabinoside triphosphate, which damages DNA when the cell cycle holds in the S phase (synthesis of DNA). Rapidly dividing cells, which require DNA replication for mitosis, are therefore most affected. Cytosine arabinoside also inhibits both DNA [12] and RNA polymerases and nucleotide reductase enzymes needed for DNA synthesis. Cytarabine is the first of a series of cancer drugs that altered the sugar component of nucleosides. Other cancer drugs modify the base. [13]
Cytarabine is often given by continuous intravenous infusion, which follows a biphasic elimination – initial fast clearance rate followed by a slower rate of the analog. [14] Cytarabine is transported into the cell primarily by hENT-1. [15] It is then monophosphorylated by deoxycytidine kinase and eventually cytarabine-5´-triphosphate, which is the active metabolite being incorporated into DNA during DNA synthesis.[ citation needed ]
Several mechanisms of resistance have been reported. [16] Cytarabine is rapidly deaminated by cytidine deaminase in the serum into the inactive uracil derivative. Cytarabine-5´-monophosphate is deaminated by deoxycytidylate deaminase, leading to the inactive uridine-5´-monophosphate analog. [17] Cytarabine-5´-triphosphate is a substrate for SAMHD1. [18] Furthermore, SAMHD1 has been shown to limit the efficacy of cytarabine efficacy in patients. [19]
When used as an antiviral, cytarabine-5´-triphosphate functions by inhibiting viral DNA synthesis. [20] Cytarabine is able to inhibit herpesvirus and vaccinia virus replication in cells during tissue culture. However, cytarabine treatment was only effective for herpesvirus infection in a murine model.[ citation needed ]
In mice, Ara-CTP (cytarabine-5'-triphosphate) blocks memory consolidation, but not short-term memory, of a context fear conditioning event. [21] The blockage of memory consolidation was proposed to be due to the inhibition by Ara-CTP of the DNA non-homologous end joining pathway. [21] Thus transient DNA breakage followed by non-homologous end joining appear to be necessary steps in the formation of a long-term memory of an event.[ citation needed ]
Isolation of arabinose-containing nucleotides from the Caribbean sponge Cryptotheca crypta (now Tectitethya crypta ) together with the realization that these compounds could act as DNA synthesis chain terminators led to exploration of these novel nucleotides as potential anticancer therapeutics. [22] Cytarabine was first synthesized in 1959 by Richard Walwick, Walden Roberts, and Charles Dekker at the University of California, Berkeley. [23]
It was approved by the United States Food and Drug Administration in June 1969, and was initially marketed in the US by Upjohn under the brand name Cytosar-U.[ citation needed ]
It is also known as ara-C (arabinofuranosyl cytidine). [24]
Ribavirin, also known as tribavirin, is an antiviral medication used to treat RSV infection, hepatitis C and some viral hemorrhagic fevers. For hepatitis C, it is used in combination with other medications such as simeprevir, sofosbuvir, peginterferon alfa-2b or peginterferon alfa-2a. It can also be used for viral hemorrhagic fevers, specifically for Lassa fever, Crimean–Congo hemorrhagic fever, and Hantavirus infection with exceptions for Ebola or Marburg infections. Ribavirin is usually taken orally or inhaled. Despite widespread usage, it has faced scrutiny in 2010 because of lack of efficacy in treating viral infections as it has historically been prescribed for.
A nucleoside triphosphate is a nucleoside containing a nitrogenous base bound to a 5-carbon sugar, with three phosphate groups bound to the sugar. They are the molecular precursors of both DNA and RNA, which are chains of nucleotides made through the processes of DNA replication and transcription. Nucleoside triphosphates also serve as a source of energy for cellular reactions and are involved in signalling pathways.
Idarubicin or 4-demethoxydaunorubicin is an anthracycline antileukemic drug. It inserts itself into DNA and prevents DNA unwinding by interfering with the enzyme topoisomerase II. It is an analog of daunorubicin, but the absence of a methoxy group increases its fat solubility and cellular uptake. Similar to other anthracyclines, it also induces histone eviction from chromatin.
Vidarabine or 9-β-D-arabinofuranosyladenine (ara-A) is an antiviral drug which is active against herpes simplex and varicella zoster viruses.
An antimetabolite is a chemical that inhibits the use of a metabolite, which is another chemical that is part of normal metabolism. Such substances are often similar in structure to the metabolite that they interfere with, such as the antifolates that interfere with the use of folic acid; thus, competitive inhibition can occur, and the presence of antimetabolites can have toxic effects on cells, such as halting cell growth and cell division, so these compounds are used in chemotherapy for cancer.
Azacitidine, sold under the brand name Vidaza among others, is a medication used for the treatment of myelodysplastic syndrome, myeloid leukemia, and juvenile myelomonocytic leukemia. It is a chemical analog of cytidine, a nucleoside in DNA and RNA. Azacitidine and its deoxy derivative, decitabine were first synthesized in Czechoslovakia as potential chemotherapeutic agents for cancer.
Clofarabine is a purine nucleoside antimetabolite marketed in the United States and Canada as Clolar. In Europe and Australia/New Zealand the product is marketed under the name Evoltra. It is FDA-approved for treating relapsed or refractory acute lymphoblastic leukaemia (ALL) in children after at least two other types of treatment have failed. Some investigations of effectiveness in cases of acute myeloid leukaemia (AML) and juvenile myelomonocytic leukaemia (JMML) have been carried out. Ongoing trials are assessing its efficacy for managing other cancers.
Nucleoside analogues are structural analogues of a nucleoside, which normally contain a nucleobase and a sugar. Nucleotide analogues are analogues of a nucleotide, which normally has one to three phosphates linked to a nucleoside. Both types of compounds can deviate from what they mimick in a number of ways, as changes can be made to any of the constituent parts. They are related to nucleic acid analogues.
Pentostatin is an anticancer chemotherapeutic drug.
Nucleic acid metabolism is a collective term that refers to the variety of chemical reactions by which nucleic acids are either synthesized or degraded. Nucleic acids are polymers made up of a variety of monomers called nucleotides. Nucleotide synthesis is an anabolic mechanism generally involving the chemical reaction of phosphate, pentose sugar, and a nitrogenous base. Degradation of nucleic acids is a catabolic reaction and the resulting parts of the nucleotides or nucleobases can be salvaged to recreate new nucleotides. Both synthesis and degradation reactions require multiple enzymes to facilitate the event. Defects or deficiencies in these enzymes can lead to a variety of diseases.
CTP synthase is an enzyme involved in pyrimidine biosynthesis that interconverts UTP and CTP.
Deoxycytidine kinase (dCK) is an enzyme which is encoded by the DCK gene in humans. dCK predominantly phosphorylates deoxycytidine (dC) and converts dC into deoxycytidine monophosphate. dCK catalyzes one of the initial steps in the nucleoside salvage pathway and has the potential to phosphorylate other preformed nucleosides, specifically deoxyadenosine (dA) and deoxyguanosine (dG), and convert them into their monophosphate forms. There has been recent biomedical research interest in investigating dCK's potential as a therapeutic target for different types of cancer.
Cytidine deaminase is an enzyme that in humans is encoded by the CDA gene.
Uridine-cytidine kinase 2 (UCK2) is an enzyme that in humans is encoded by the UCK2 gene.
CTP synthase 1 is an enzyme that is encoded by the CTPS1 gene in humans. CTP synthase 1 is an enzyme in the de novo pyrimidine synthesis pathway that catalyses the conversion of uridine triphosphate (UTP) to cytidine triphosphate (CTP). CTP is a key building block for the production of DNA, RNA and some phospholipids.
PMEG is an acyclic nucleoside phosphonate. Acyclic nucleoside phosphonates can have significant antiviral, cytostatic and antiproliferative activities. PMEG can inhibit cell proliferation and cause genotoxicity. PMEG is active against leukemia and melanoma in animal tumor models, and also has antiviral activities against herpes viruses in murine models.
Arabinopyranosyl-N-methyl-N-nitrosourea, also known as Aranose (Араноза) is a cytostatic anticancer chemotherapeutic drug of an alkylating type. Chemically it is a nitrosourea derivative. It was developed in the Soviet Union in the 1970s. It was claimed by its developers that its advantages over other nitrosoureas are a relatively low hematological toxicity and a wider therapeutic index, which allows for its outpatient administration.
ADE is a chemotherapy regimen most often used as an induction or consolidation regimen in acute myelogenous leukemia, especially in poor-risk patients or those refractory to the standard first-line induction with standard "7+3" regimen or who are relapsed after the standard chemotherapy.
Janet Rideout is an organic chemist and one of the scientists who discovered that azidothymidine (AZT) could be used as an antiretroviral agent to treat Human Immunodeficiency Virus (HIV). She also played a key role in the development of acyclovir, the first effective treatment for herpes simplex virus.
Lobucavir is an antiviral drug that shows broad-spectrum activity against herpesviruses, hepatitis B and other hepadnaviruses, HIV/AIDS and cytomegalovirus. It initially demonstrated positive results in human clinical trials against hepatitis B with minimal adverse effects but was discontinued from further development following the discovery of increased risk of cancer associated with long-term use in mice. Although this carcinogenic risk is present in other antiviral drugs, such as zidovudine and ganciclovir that have been approved for clinical use, development was halted by Bristol-Myers Squibb, its manufacturer.