Accession NumberDB04858
TypeSmall Molecule

Tirapazamine (SR-4233) is an experimental anticancer drug that is activated to a toxic radical only at very low levels of oxygen (hypoxia). Such levels are common in human solid tumors, a phenomenon known as tumor hypoxia. Thus, tirapazamine is activated to its toxic form preferentially in the hypoxic areas of solid tumors. Cells in these regions are resistant to killing by radiotherapy and most anticancer drugs. Thus the combination of tirapazamine with conventional anticancer treatments is particularly effective. As of 2006, tirapazamine is undergoing phase III testing in patients with head and neck cancer and gynecological cancer, and similar trials are being undertaken for other solid tumor types. [Wikipedia]

1,2,4-benzotriazin-3-amine, 1,4-dioxide
3-Amino-1,2,4-benzotriazine 1,4-dioxide
External IDs SR 4233 / SR-259075 / SR-4233 / SR259075 / WIN 59075 / WIN-59075
Product Ingredients Not Available
Approved Prescription ProductsNot Available
Approved Generic Prescription ProductsNot Available
Approved Over the Counter ProductsNot Available
Unapproved/Other Products Not Available
International Brands
Brand mixturesNot Available
CAS number27314-97-2
WeightAverage: 178.151
Monoisotopic: 178.049075449
Chemical FormulaC7H6N4O2

For the treatment of head and neck cancer.

Structured Indications Not Available

Tirapazamine is a anticancer drug that is inactive in normal tissues that are well oxygenated, but becomes active at the low oxygen levels found in solid tumors. As a result, the drug kills these poorly oxygenated or hypoxic cells while limiting toxicity in normal tissue. Tirapazamine may prove highly effective when used in combination with standard anticancer therapy, as these hypoxic cells are characteristically resistant to radiation and common anticancer agents.

Mechanism of action

Extensive preclinical testing has established that the mechanism for the selective toxicity towards hypoxic cells is the result of a one-electron reduction of the parent molecule to a free radical species that interacts with DNA to produce single- and double-strand breaks and lethal chromosome aberrations. It has also shown activity when combined with fractionated irradiation and when combined with some chemotherapy agents, particularly cisplatin and carboplatin.

TargetKindPharmacological actionActionsOrganismUniProt ID
DNANucleotideunknownNot AvailableHumannot applicabledetails
Related Articles
AbsorptionNot Available
Volume of distributionNot Available
Protein bindingNot Available
MetabolismNot Available
Route of eliminationNot Available
Half lifeNot Available
ClearanceNot Available
ToxicityNot Available
Affected organisms
  • Humans and other mammals
PathwaysNot Available
Pharmacogenomic Effects/ADRs Not Available
Drug Interactions
DrugInteractionDrug group
AcetyldigitoxinAcetyldigitoxin may decrease the cardiotoxic activities of Tirapazamine.Approved
BevacizumabBevacizumab may increase the cardiotoxic activities of Tirapazamine.Approved, Investigational
CabazitaxelThe risk or severity of adverse effects can be increased when Cabazitaxel is combined with Tirapazamine.Approved
ClotrimazoleThe metabolism of Tirapazamine can be decreased when combined with Clotrimazole.Approved, Vet Approved
CyclophosphamideCyclophosphamide may increase the cardiotoxic activities of Tirapazamine.Approved, Investigational
Cyproterone acetateThe serum concentration of Tirapazamine can be decreased when it is combined with Cyproterone acetate.Approved, Investigational
DeslanosideDeslanoside may decrease the cardiotoxic activities of Tirapazamine.Approved
DigitoxinDigitoxin may decrease the cardiotoxic activities of Tirapazamine.Approved
DigoxinDigoxin may decrease the cardiotoxic activities of Tirapazamine.Approved
DisulfiramThe metabolism of Tirapazamine can be decreased when combined with Disulfiram.Approved
DocetaxelThe risk or severity of adverse effects can be increased when Docetaxel is combined with Tirapazamine.Approved, Investigational
IsoniazidThe metabolism of Tirapazamine can be decreased when combined with Isoniazid.Approved
NicotineThe metabolism of Tirapazamine can be decreased when combined with Nicotine.Approved
OleandrinAnvirzel may decrease the cardiotoxic activities of Tirapazamine.Experimental
OuabainOuabain may decrease the cardiotoxic activities of Tirapazamine.Approved
PaclitaxelThe risk or severity of adverse effects can be increased when Paclitaxel is combined with Tirapazamine.Approved, Vet Approved
TiclopidineThe metabolism of Tirapazamine can be decreased when combined with Ticlopidine.Approved
TrastuzumabTrastuzumab may increase the cardiotoxic activities of Tirapazamine.Approved, Investigational
Food InteractionsNot Available
Synthesis ReferenceNot Available
General References
  1. Denny WA: Prospects for hypoxia-activated anticancer drugs. Curr Med Chem Anticancer Agents. 2004 Sep;4(5):395-9. [PubMed:15379691 ]
  2. Gandara DR, Lara PN Jr, Goldberg Z, Le QT, Mack PC, Lau DH, Gumerlock PH: Tirapazamine: prototype for a novel class of therapeutic agents targeting tumor hypoxia. Semin Oncol. 2002 Feb;29(1 Suppl 4):102-9. [PubMed:11894020 ]
  3. Zeman EM, Brown JM, Lemmon MJ, Hirst VK, Lee WW: SR-4233: a new bioreductive agent with high selective toxicity for hypoxic mammalian cells. Int J Radiat Oncol Biol Phys. 1986 Jul;12(7):1239-42. [PubMed:3744945 ]
External Links
ATC CodesNot Available
AHFS CodesNot Available
PDB EntriesNot Available
FDA labelNot Available
MSDSNot Available
Clinical Trials
Clinical Trials
1CompletedTreatmentCervical Cancers1
1CompletedTreatmentLung Cancers2
1CompletedTreatmentUnspecified Adult Solid Tumor, Protocol Specific1
1CompletedTreatmentUnspecified Childhood Solid Tumor, Protocol Specific1
2CompletedTreatmentAlveolar Childhood Rhabdomyosarcoma / Embryonal Childhood Rhabdomyosarcoma / Embryonal-botryoid Childhood Rhabdomyosarcoma / Previously Treated Childhood Rhabdomyosarcoma / Recurrent Childhood Rhabdomyosarcoma1
2CompletedTreatmentCancer, Ovarian / Primary Peritoneal Cavity Cancer1
2CompletedTreatmentCervical Cancers1
2CompletedTreatmentLimited Stage Small Cell Lung Cancer1
2CompletedTreatmentSquamous Neck Carcinoma of the Head and Neck Cancer (SCCHN)1
2Not Yet RecruitingTreatmentHepatocellular,Carcinoma1
3CompletedTreatmentAdenocarcinoma of the Cervix / Cervical Adenosquamous Cell Carcinoma / Cervical Squamous Cell Carcinoma / Stage IB Cervical Cancer / Stage IIA Cervical Cancer / Stage IIB Cervical Cancer / Stage III Cervical Cancer / Stage IVA Cervical Cancer1
3CompletedTreatmentHead and Neck Squamous Cell Carcinoma (HNSCC)1
3CompletedTreatmentLung Cancers2
3CompletedTreatmentNeoplasms, Head and Neck1
ManufacturersNot Available
PackagersNot Available
Dosage formsNot Available
PricesNot Available
PatentsNot Available
Experimental PropertiesNot Available
Predicted Properties
Water Solubility3.93 mg/mLALOGPS
pKa (Strongest Acidic)12.97ChemAxon
pKa (Strongest Basic)2.18ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area92.79 Å2ChemAxon
Rotatable Bond Count0ChemAxon
Refractivity56.94 m3·mol-1ChemAxon
Polarizability15.97 Å3ChemAxon
Number of Rings2ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Predicted ADMET features
Human Intestinal Absorption+0.7534
Blood Brain Barrier+0.8055
Caco-2 permeable-0.5073
P-glycoprotein substrateNon-substrate0.6092
P-glycoprotein inhibitor INon-inhibitor0.8876
P-glycoprotein inhibitor IINon-inhibitor0.9664
Renal organic cation transporterNon-inhibitor0.8659
CYP450 2C9 substrateNon-substrate0.7746
CYP450 2D6 substrateNon-substrate0.8235
CYP450 3A4 substrateNon-substrate0.5581
CYP450 1A2 substrateInhibitor0.6016
CYP450 2C9 inhibitorNon-inhibitor0.6654
CYP450 2D6 inhibitorNon-inhibitor0.8474
CYP450 2C19 inhibitorNon-inhibitor0.662
CYP450 3A4 inhibitorNon-inhibitor0.921
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.7748
Ames testAMES toxic0.7746
BiodegradationNot ready biodegradable0.9644
Rat acute toxicity2.5331 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.5063
hERG inhibition (predictor II)Non-inhibitor0.7149
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397 )
Mass Spec (NIST)Not Available
SpectraNot Available
DescriptionThis compound belongs to the class of organic compounds known as aminotriazines. These are organic compounds containing an amino group attached to a triazine ring.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
Sub ClassAminotriazines
Direct ParentAminotriazines
Alternative ParentsBenzenoids / 1,2,4-triazines / Heteroaromatic compounds / Azacyclic compounds / Primary amines / Organic salts / Organic oxides / Hydrocarbon derivatives / Organic cations
SubstituentsAminotriazine / 1,2,4-triazine / Benzenoid / Heteroaromatic compound / Azacycle / Organic nitrogen compound / Organic oxygen compound / Organic oxide / Hydrocarbon derivative / Organic salt
Molecular FrameworkAromatic heteropolycyclic compounds
External Descriptorsaromatic amine, N-oxide, benzotriazines (CHEBI:78887 )


1. DNA
Pharmacological action
General Function:
Used for biological information storage.
Specific Function:
DNA contains the instructions needed for an organism to develop, survive and reproduce.
Molecular Weight:
2.15 x 1012 Da


Pharmacological action
General Function:
Steroid hydroxylase activity
Specific Function:
Metabolizes several precarcinogens, drugs, and solvents to reactive metabolites. Inactivates a number of drugs and xenobiotics and also bioactivates many xenobiotic substrates to their hepatotoxic or carcinogenic forms.
Gene Name:
Uniprot ID:
Uniprot Name:
Cytochrome P450 2E1
Molecular Weight:
56848.42 Da
  1. Khan S, O'Brien PJ: Molecular mechanisms of tirapazamine (SR 4233, Win 59075)-induced hepatocyte toxicity under low oxygen concentrations. Br J Cancer. 1995 Apr;71(4):780-5. [PubMed:7710944 ]
Drug created on October 18, 2007 18:36 / Updated on September 01, 2017 11:22