title: Human pharmacokinetics of nitrazepam: effect of age and diseases.
abstract: Plasma concentrations of nitrazepam were measured by gas-liquid chromatography in: young healthy volunteers, in geriatric and psychiatric patients and in epileptic children. The disposition of nitrazepam was described in terms of a two-compartment open model. After a single oral dose of nitrazepam 5 mg the most prominent differences between the experimental groups were in the beta-phase half-life mean 29 h in the young volunteers and 40 h in geriatric patients , and in the apparent volume of distribution during the beta-phase of 2.4 vs 4.8 1/kg. Total plasma clearance and the average steady state concentration in both groups were equal. The plasma level rose at a rate proportional to the beta-phase half-life, and so, they were achieved more rapidly in the young than in the old subjects (3.5 vs 7.5 d). No change in steady-state level or in the half-life of nitrazepam were found during long term treatment, which indicates lack of enzyme induction or inhibition. In 95% of the epileptic children with a good to fair clinical response, the plasma concentration of nitrazepam was 40-180 ng/ml (mean 114 ng/ml). As all of the patients were on combined antiepileptic therapy, no attempt was made to correlate plasma level with therapeutic response.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D004194:Disease / Q000378:metabolism; D005260:Female; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009567:Nitrazepam / Q000009:adverse effects / Q000378:metabolism*; D013997:Time Factors
chemical_list: D009567:Nitrazepam