Triazolam 0.25 mg was compared with nitrazepam 5 mg as a hypnotic for 26 geriatric inpatients in a double-blind cross-over study. Sleep quantity and quality and psychomotor performance were studied. The sleep quantity and quality were similar for both drugs. There were no statistically significant differences between the two drugs in the psychomotor tests. The results are in contrast to results from other studies and might be explained by the composition of the patient material in the present study.

Serum triazolam levels were determined in eight geriatric patients (average age 80 years) on Days 1 and 7 of administration of triazolam 0.25 mg once daily, 1 h after a standard breakfast. Triazolam was rapidly absorbed reaching average peak concentrations of 2.0 and 2.04 ng/ml, 1.5 and 1.38 h after administration on Days 1 and 7, respectively. The mean apparent elimination half-life was 1.41 h (range 0.73-4.13 h) on Day 1 and 1.37 h (range 0.69-3.36 h) on Day 7. There was no significant difference between mean serum triazolam concentrations or pharmacokinetic parameters on Days 1 and 7 of the treatment. Serum samples were also assayed for alpha-hydroxytriazolam, an active metabolite of triazolam, but none could be detected in any of the samples from Days 1 or 7, assay sensitivity 0.09 ng/2 ml serum. The range of half-lives of triazolam in the patients in the present study is in close agreement with that previously reported in elderly subjects. The study provides further evidence of the lack of change in pharmacokinetic parameters on multiple dosing and that drug accumulation did not occur.

The therapeutic efficacy, tolerability and pharmacokinetics of zimeldine in elderly depressed patients were evaluated after administration of different doses of the drug in once daily evening doses. The doses of zimeldine were 100 mg during the first 2 weeks, 150 mg during the next 2 weeks and 200 mg during the last 2 weeks. Nine of the 11 patients (mean age 78 years) included in the study completed the 6-week treatment period, and all nine improved according to the Hamilton depression rating scale. The drug was well tolerated and the side effects were few and mild. No influence of clinical importance was noted in haematology, liver and kidney functions, EEG, blood pressure or pulse rate. Steady-state plasma concentrations of zimeldine, and its active metabolite norzimeldine, were achieved in most cases after 1 week of treatment in each dose regimen. The plasma concentrations increased linearly with the increase in dose. The maximal interindividual variations in plasma concentrations were 8-fold for zimeldine and 3-fold for norzimeldine . The plasma levels of both zimeldine and norzimeldine were higher in the elderly than reported earlier in younger patients. The ratio of norzimeldine/zimeldine concentrations was reduced in the elderly, indicating a reduction of the metabolic capacity. The results suggest that zimeldine can be administered in a once daily dosage regimen to elderly patients, but they should be given a lower dose than younger patients.