Detection of a reactive metabolite of misonidazole in human urine.

Chemical studies have indicated that, following reduction of misonidazole to the hydroxylamine derivative, reaction with guanosine leads to the formation of a 2-carbon addition product of guanosine. In this study, the formation of the guanosine product is used to detect the presence of a reactive metabolite of misonidazole in the urine of patients treated with misonidazole. Urine samples were incubated with [14C]guanosine and the guanosine product was separated by HPLC analysis. The quantities of product vary as much as 10-fold from patient to patient and it is suggested that the assay might be useful as a predictor of patients susceptible to the development of peripheral neuropathy or other effects of misonidazole.