PHARMACOKINETICS OF NITROXAZEPINE IN DEPRESSED PATIENTS

A pharmacokinetic study was done on 10 depressed patients (DSM-III-R 296.3). The patients were treated with Sintamil (R) (nitroxazepine HCl) with titrated dose from 75 mg to 225 mg for 6 weeks. Plasma levels of nitroxazepine (Sintamil (R)) and its metabolites desmethyl (D), N-oxide (N-O) and carboxylic acid (c) were estimated. Anti-depressant efficacy was judged by reduction in Hamilton Rating Depression Scale (HDRS) scores, and tolerability was monitored by reports of unwanted effects. The overall reduction in HDRS score was about 50% by 6 weeks. The plasma levels of nitroxazepin (ng/ral) showed a rise from a mean ( +SEM) level. 47.0 4-7.3 on day 1 (dose 75 mg) to 129.84-24.6 on day 7 (dose 150 mg) (p< 0.01) and remained steady till day 21. There were large interindividual variations. The metabolites followed a similar pattern. The HDRS score showed a steady reduction between day 14 and 42 when the levels of nitroxizepine and des-methyl metabolites were maintained between 176.5 ng/ml to 251 ng/ml.