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Accession NumberDB00552  (APRD00202)
TypeSmall Molecule
GroupsApproved, Investigational

A potent inhibitor of adenosine deaminase. The drug is effective in the treatment of many lymphoproliferative malignancies, particularly hairy-cell leukemia. It is also synergistic with some other antineoplastic agents and has immunosuppressive activity. [PubChem]

Co-vidarabineNot AvailableIS
NipentNot AvailableNot Available
Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Nipentinjection, powder, lyophilized, for solution2 mg/mLintravenousHospira, Inc.1991-10-11Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Generic Prescription ProductsNot Available
Over the Counter ProductsNot Available
International BrandsNot Available
Brand mixturesNot Available
SaltsNot Available
CAS number53910-25-1
WeightAverage: 268.2691
Monoisotopic: 268.11715502
Chemical FormulaC11H16N4O4
DescriptionThis compound belongs to the class of organic compounds known as imidazodiazepines. These are organic compounds containing an imidazole ring fused to a diazepine ring. Imidazole is 5-membered ring consisting of three carbon atoms, and two nitrogen centers at the 1- and 3-positions. Diazepine is a 7-membered ring consisting of five carbon and two nitrogen atoms.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
Sub ClassNot Available
Direct ParentImidazodiazepines
Alternative Parents
  • Imidazodiazepine
  • Imidazo-meta-diazepine
  • Meta-diazepine
  • N-substituted imidazole
  • Saccharide
  • Heteroaromatic compound
  • Oxolane
  • Imidazole
  • Azole
  • Secondary alcohol
  • Oxacycle
  • Azacycle
  • Organic 1,3-dipolar compound
  • Propargyl-type 1,3-dipolar organic compound
  • Carboxylic acid amidine
  • Amidine
  • Hydrocarbon derivative
  • Primary alcohol
  • Organooxygen compound
  • Organonitrogen compound
  • Alcohol
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External DescriptorsNot Available
IndicationFor the treatment of hairy cell leukaemia refractory to alpha interferon.
PharmacodynamicsPentostatin is an antineoplastic anti-metabolite used in the treatment of several forms of leukemia including acute nonlymphocytic leukemia and hairy cell leukemia. Anti-metabolites masquerade as purine or pyrimidine - which become the building blocks of DNA. They prevent these substances becoming incorporated in to DNA during the "S" phase (of the cell cycle), stopping normal development and division. It is a 6-thiopurine analogue of the naturally occurring purine bases hypoxanthine and guanine. Intracellular activation results in incorporation into DNA as a false purine base. An additional cytotoxic effect is related to its incorporation into RNA. Cytotoxicity is cell cycle phase-specific (S-phase).
Mechanism of actionPentostatin is a potent transition state inhibitor of adenosine deaminase (ADA), the greatest activity of which is found in cells of the lymphoid system. T-cells have higher ADA activity than B-cells, and T-cell malignancies have higher activity than B-cell malignancies. The cytotoxicity that results from prevention of catabolism of adenosine or deoxyadenosine is thought to be due to elevated intracellular levels of dATP, which can block DNA synthesis through inhibition of ribonucleotide reductase. Intracellular activation results in incorporation into DNA as a false purine base. An additional cytotoxic effect is related to its incorporation into RNA. Cytotoxicity is cell cycle phase-specific (S-phase).
AbsorptionNot absorbed orally, crosses blood brain barrier.
Volume of distributionNot Available
Protein binding4%

Primarily hepatic, but only small amounts are metabolized.

Route of eliminationIn man, following a single dose of 4 mg/m2 of pentostatin infused over 5 minutes, approximately 90% of the dose was excreted in the urine as unchanged pentostatin and/or metabolites as measured by adenosine deaminase inhibitory activity.
Half life5.7 hours (with a range between 2.6 and 16 hrs)
  • 68 mL/min/m2
ToxicityLD50=128 mg/kg (mouse), side effects include lethargy, rash, fatigue, nausea and myelosuppression.
Affected organisms
  • Humans and other mammals
  • Mycobacterium tuberculosis
  • Pseudomonas aeruginosa
  • Leptospira interrogans
  • Borrelia burgdorferi
  • Vibrio cholerae
  • Escherichia coli
  • Salmonella typhi
  • Staphylococcus aureus
  • Serratia marcescens
  • Proteus vulgaris
  • Klebsiella
  • Shigella
PathwaysNot Available
SNP Mediated EffectsNot Available
SNP Mediated Adverse Drug ReactionsNot Available
Predicted ADMET features
Human Intestinal Absorption+0.8204
Blood Brain Barrier+0.911
Caco-2 permeable-0.7031
P-glycoprotein substrateSubstrate0.6194
P-glycoprotein inhibitor INon-inhibitor0.8993
P-glycoprotein inhibitor IINon-inhibitor0.89
Renal organic cation transporterNon-inhibitor0.8513
CYP450 2C9 substrateNon-substrate0.7946
CYP450 2D6 substrateNon-substrate0.7974
CYP450 3A4 substrateSubstrate0.5207
CYP450 1A2 substrateNon-inhibitor0.8771
CYP450 2C9 substrateNon-inhibitor0.9117
CYP450 2D6 substrateNon-inhibitor0.9211
CYP450 2C19 substrateNon-inhibitor0.8969
CYP450 3A4 substrateNon-inhibitor0.9421
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.9626
Ames testNon AMES toxic0.7627
BiodegradationNot ready biodegradable0.9961
Rat acute toxicity2.2716 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.987
hERG inhibition (predictor II)Non-inhibitor0.6424
  • Hospira inc
  • Bedford laboratories
Dosage forms
Injection, powder, lyophilized, for solutionintravenous2 mg/mL
Unit descriptionCostUnit
Pentostatin 10 mg vial2280.0USD vial
Nipent 10 mg vial1891.31USD vial
DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.
PatentsNot Available
Experimental Properties
melting point220 °CPhysProp
water solubility30 mg/mLNot Available
logP-1.1Not Available
pKa5.2MERCK INDEX (1996)
Predicted Properties
Water Solubility10.7 mg/mLALOGPS
pKa (Strongest Acidic)13.06ChemAxon
pKa (Strongest Basic)8.33ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count7ChemAxon
Hydrogen Donor Count4ChemAxon
Polar Surface Area112.13 Å2ChemAxon
Rotatable Bond Count2ChemAxon
Refractivity64.98 m3·mol-1ChemAxon
Polarizability26.44 Å3ChemAxon
Number of Rings3ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Mass Spec (NIST)Not Available
SpectraNot Available
Synthesis Reference

Nadji Sourena, “Process for the production of pentostatin aglycone and pentostatin.” U.S. Patent US20040181052, issued September 16, 2004.

General Reference
  1. Link
External Links
ATC CodesL01XX08
AHFS CodesNot Available
PDB EntriesNot Available
FDA labelNot Available
MSDSDownload (56.7 KB)
Drug Interactions
ClozapineMyelosuppressive Agents may enhance the adverse/toxic effect of CloZAPine. Specifically, the risk for agranulocytosis may be increased.
CyclophosphamideMay enhance the cardiotoxic effect of Cyclophosphamide.
DenosumabMay enhance the adverse/toxic effect of Immunosuppressants. Specifically, the risk for serious infections may be increased.
FludarabineMay enhance the adverse/toxic effect of Pentostatin. Pentostatin may enhance the adverse/toxic effect of Fludarabine. Pulmonary toxicity is of specific concern.
LeflunomideImmunosuppressants may enhance the adverse/toxic effect of Leflunomide. Specifically, the risk for hematologic toxicity such as pancytopenia, agranulocytosis, and/or thrombocytopenia may be increased.
NatalizumabImmunosuppressants may enhance the adverse/toxic effect of Natalizumab. Specifically, the risk of concurrent infection may be increased.
NelarabinePentostatin may diminish the antineoplastic effect of Nelarabine. Conversion of nelarabine, a pro-drug, to its active form may be inhibited by pentostatin.
Pegademase bovinePegademase Bovine may diminish the therapeutic effect of Pentostatin. Pentostatin may diminish the therapeutic effect of Pegademase Bovine.
PimecrolimusMay enhance the adverse/toxic effect of Immunosuppressants.
RoflumilastMay enhance the immunosuppressive effect of Immunosuppressants.
Sipuleucel-TImmunosuppressants may diminish the therapeutic effect of Sipuleucel-T.
TofacitinibImmunosuppressants may enhance the immunosuppressive effect of Tofacitinib.
TrastuzumabMay enhance the neutropenic effect of Immunosuppressants.
Food InteractionsNot Available


1. Adenosine deaminase

Kind: protein

Organism: Human

Pharmacological action: yes

Actions: inhibitor


Name UniProt ID Details
Adenosine deaminase P00813 Details


  1. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. Pubmed
  2. Jackson RC, Leopold WR, Ross DA: The biochemical pharmacology of (2’-R)-chloropentostatin, a novel inhibitor of adenosine deaminase. Adv Enzyme Regul. 1986;25:125-39. Pubmed
  3. Newman DJ, Cragg GM: Natural products as sources of new drugs over the last 25 years. J Nat Prod. 2007 Mar;70(3):461-77. Epub 2007 Feb 20. Pubmed
  4. Cabanillas F: Purine nucleoside analogs in indolent non-Hodgkin’s lymphoma. Oncology (Williston Park). 2000 Jun;14(6 Suppl 2):13-5. Pubmed

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Drug created on June 13, 2005 07:24 / Updated on February 18, 2014 20:51