Single- and multiple-dose pharmacokinetics of terodiline in geriatric patients

As a target group, geriataric patients were selected for pharmacokinetic studies with terodiline (Mictrol), an anticholinergic and calcium antagonist drug effective in the treatment of urinary incontinence. The single-dose kinetics in the geriatric patients (mean age 82 years) differed significantly from that previously found (Hallén et al. 1987) in healthy volunteers (mean age 35 years). There were higher peak serum concentrations (110 vs 79 micrograms.l-1), increased half-life (189 vs 60 h), lower renal clearance (4.0 vs 10.9 ml.min-1) and lower total clearance (29 vs 75 ml.min-1). Multiple-doses of 12.5 mg b.d. for 6-8 weeks resulted in a mean steady-state concentration of 642 micrograms.l-1, which was in agreement with the single dose parameters. The studied geriatric patients can be characterized not only as old, but also as frail, bedridden, having several diseases and polymedicated. The differences in pharmacokinetics between younger and elderly subjects can be attributed to a variety of complex factors, which may alter the clearance and/or the volume of distribution.