Excretion of triamterene and its metabolite in triamterene stone patients.

As triamterene users may form kidney stones containing deposits of triamterene and its metabolites, we studied urinary excretion to detect any altered metabolism of triamterene in these patients. We found no significant differences between patients and matched control subjects in total recovery, hourly excretion patterns, and concentrations of triamterene and its sulfate metabolite. Approximately half of all subjects tested revealed urine concentrations of the sulfate metabolite that exceeded the observed solubility limit.