Medicolegal aspects of tetrazepam metabolism.

The benzodiazepine tetrazepam is primarily muscle relaxant with comparably lower central sedating effects and is therefore commonly prescribed for muscle spasms of different origins. To evaluate tetrazepam metabolism, a study was conducted with ten healthy volunteers. Blood and urine samples were regularly collected after the intake of 50 mg tetrazepam. Toxicological analyses revealed that tetrazepam is also metabolized to diazepam and further to nordazepam, which has not yet been reported. Tetrazepam and diazepam could be detected in urine samples at least 72 h after intake, the diazepam concentration being 33% (+/-14% SD), on average, of the tetrazepam concentration. On the basis of three case histories, the importance of the detection of these newly described metabolites is shown as necessary to prevent false accusations and potential negative legal consequences for examined persons.