Pharmacokinetics of amitriptyline in the elderly

The pharmacokinetics of amitryptyline (AMI) have been evaluated in six healthy elderly volunteers (72-83 years of age) after a single dose of 125 mg of AMI-HCl. AMI was absorbed rather slowly (mean peak time 10.4 +/- 1.6 hrs) but very efficiently (F: 0.59-0.75). The rate of formation of nortriptyline (NT) as well as the appearance clearance values (0.18-0.45 l/h/kg) of AMI were significantly lower than those previously described for younger subjects. Reversible alterating ECG were observed in 5 cases concomitantly with AMI peak plasma concentrations. The results indicate the desirability of reduced and/or divided daily doses of AMI in the elderly.