TRANSDERMAL FENTANYL DISPOSITION IN ELDERLY SUBJECTS

The pharmacokinetic characteristics of a 20-cm(2) fentanyl 24-hour tra nsdermal patch were compared between 10 healthy elderly subjects 67-87 years and 6 young subjects 19-27 years. All 10 elderly subjects requi red patch removal prior to 24 h due to adverse effects versus none of the young subjects. The mean patch duration (PD) in elderly subjects w as 11.7 +/- 4.9 h, yielding a mean area under the curve from 0 to 60 h (AUC(0-60)) of 20.4 +/- 10.3 ng h/ml versus a mean AUC(0-60) of 21.0 +/- 10.4 ng h/ml in young subjects. Correcting AUC(0-60) for PD (AUC(0 -60)/PD) gave a mean value of 2.05 +/- 1.10 ng/ml for elderly subjects , which was significantly greater than the AUC(0-60)/PD of 0.88 +/- 0. 44 ng/ml in young subjects (p = 0.034, Student's t test). The higher s erum concentrations reflect increased absorption and/or decreased clea rance in the elderly.