Pharmacokinetics of alprazolam in geriatric patients with neurotic depression

The pharmacokinetics of alprazolam was studied in 10 geriatric patients (5 males, 5 females) with neurotic depression during a 6-week period. After 0.5 mg of alprazolam on Day 1 the mean elimination half-life was 11.1 hr and Cmax 12.3 ng/ml. The pharmacokinetic evaluation on Day 1 (t 1/2, tmax) did not differ significantly from the evaluation on Day 42. The mean daily dosage on Day 42 was 1.6 mg alprazolam. The concentrations of the metabolites alpha-OH alprazolam and 4-OH alprazolam were less than 10% of that of alprazolam. All the patients improved clinically. The most common side effect was drowsiness, more often during the first week than the last week.