| Item |
Information |
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Drug Groups
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approved |
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Description
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Positional isomer of cyclophosphamide which is active as an alkylating agent and an immunosuppressive agent. [PubChem] |
| Indication |
Used as a component of various chemotherapeutic regimens as third-line therapy for recurrent or refractory germ cell testicular cancer. Also used as a component of various chemotherapeutic regimens for the treatment of cervical cancer, as well as in conjunction with surgery and/or radiation therapy in the treatment of various soft tissue sarcomas. Other indications include treatment of osteosarcoma, bladder cancer, ovarian cancer. small cell lung cancer, and non-Hodgkin's lymphoma. |
| Pharmacology |
Ifosfamide requires activation by microsomal liver enzymes to active metabolites in order to exert its cytotoxic effects. Activation occurs by hydroxylation at the ring carbon atom 4 to form the unstable intermediate 4-hydroxyifosfamide. This metabolite than rapidly degrades to the stable urinary metabolite 4-ketoifosfamide. The stable urinary metabolite, 4-carboxyifosfamide, is formed upon opening of the ring. These urinary metabolites have not been found to be cytotoxic. N, N-bis (2-chloroethyl)-phosphoric acid diamide (ifosphoramide) and acrolein are also found. The major urinary metabolites, dechloroethyl ifosfamide and dechloroethyl cyclophosphamide, are formed upon enzymatic oxidation of the chloroethyl side chains and subsequent dealkylation. It is the alkylated metabolites of ifosfamide that have been shown to interact with DNA. Ifosfamide is cycle-phase nonspecific. |
| Toxicity |
LD50 (mouse) = 390-1005 mg/kg, LD50 (rat) = 150-190 mg/kg. Side effects include nausea, vomiting and myelosuppression. Toxic effects include central nervous system toxicity (confusion, hallucinations) and urotoxic effects (cystitis, blood in urine). |
| Affected Organisms |
| • |
Humans and other mammals |
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| Biotransformation |
Primarily hepatic |
| Half Life |
7-15 hours |
| Protein Binding |
Minimal |
| Elimination |
Ifosfamide is extensively metabolized in humans and the metabolic pathways appear to be saturated at high doses. After administration of doses of 5 g/m2 of 14C-labeled ifosfamide, from 70% to 86% of the dosed radioactivity was recovered in the urine, with about 61% of the dose excreted as parent compound. At doses of 1.6–2.4 g/m2 only 12% to 18% of the dose was excreted in the urine as unchanged drug within 72 hours. |
| References |
| • |
Furlanut M, Franceschi L: Pharmacology of ifosfamide. Oncology. 2003;65 Suppl 2:2-6.
[Pubmed]
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Fleming RA: An overview of cyclophosphamide and ifosfamide pharmacology. Pharmacotherapy. 1997 Sep-Oct;17(5 Pt 2):146S-154S.
[Pubmed]
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Wagner T: Ifosfamide clinical pharmacokinetics. Clin Pharmacokinet. 1994 Jun;26(6):439-56.
[Pubmed]
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Allen LM, Creaven PJ, Nelson RL: Studies on the human pharmacokinetics of isophosphamide (NSC-109724). Cancer Treat Rep. 1976 Apr;60(4):451-8.
[Pubmed]
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Brade WP, Herdrich K, Varini M: Ifosfamide--pharmacology, safety and therapeutic potential. Cancer Treat Rev. 1985 Mar;12(1):1-47.
[Pubmed]
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Zalupski M, Baker LH: Ifosfamide. J Natl Cancer Inst. 1988 Jun 15;80(8):556-66.
[Pubmed]
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Willits I, Price L, Parry A, Tilby MJ, Ford D, Cholerton S, Pearson AD, Boddy AV: Pharmacokinetics and metabolism of ifosfamide in relation to DNA damage assessed by the COMET assay in children with cancer. Br J Cancer. 2005 May 9;92(9):1626-35.
[Pubmed]
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Lokiec F: Ifosfamide: pharmacokinetic properties for central nervous system metastasis prevention. Ann Oncol. 2006 May;17 Suppl 4:iv33-6.
[Pubmed]
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Schoenike SE, Dana WJ: Ifosfamide and mesna. Clin Pharm. 1990 Mar;9(3):179-91.
[Pubmed]
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Dechant KL, Brogden RN, Pilkington T, Faulds D: Ifosfamide/mesna. A review of its antineoplastic activity, pharmacokinetic properties and therapeutic efficacy in cancer. Drugs. 1991 Sep;42(3):428-67.
[Pubmed]
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