Pharmacokinetics of N-demethyldiazepam in patients suffering from insomnia and treated with nortriptyline.

1 Hospitalized patients suffering from insomnia were treated with N-demethyldiazepam (30 mg p.o.) for 10 days, while continuing treatment with nortriptyline (75 or 100 mg daily). 2 Clinical evaluation performed by objective rating scales showed a positive therapeutic effect. No correlation was found however between drug plasma levels and clinical efficacy. A high inter-individual variability was observed. 3 In three cases the N-demethyldiazepam disappearance curve showed a biexponential decay, with a slow first component followed by a faster one. 4 Compared with diazepam the tested drug has a longer plasma apparent half-life and a lower relative clearance.