Cladribine toxicity

Cladribine, or 2-chlorodeoxyadenosine, is resistant to adenosine deaminase and after intracellular phosphorylation by deoxycytidine kinase, it is incorporated into DNA. It is considered the drug of choice in hairy cell leukemia because of high activity combined with acceptable toxicity. Cladribine shows variable oral absorbtion and is usually administered intravenously. Its concentration-time course is biphasic with plasma half-lives of 35 minutes and 6.7 hours. Excretion is primarily by the kidneys. Its most prominent dose-limiting toxicity is myelosup-pression. 

The major dose-limiting toxicity of cladribine is myelo-suppression. Cumulative thrombocytopenia may occur with repeated courses. Opportunistic infections are common and are correlated with decreased CD4+ ceU counts. Other toxic effects include nausea, infections, high fever, headache, fatigue, skin rashes, and tumor lysis syndrome. Neurological and immunosuppressive adverse effects are less evident than with pentostatin at cliiucally active doses. Pentostatin,... 

Cladribine is indicated in the treatment of hairy cell leukemia, whereas fludarabine phosphate is utilized in chronic lymphocytic leukemia. In addition to myelosuppression, fludarabine phosphate can induce hemolytic anemia, and severe CNS toxicity has been noted with high doses. 

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