Influence of Age on the Pharmacokinetics and Pharmacodynamics of Oral Transmucosal Fentanyl Citrate

Background: Cancer pain is primarily a problem of older persons. Oral transmucosal fentanyl citrate (OTF) was devel-oped to provide rapid analgesia and is the first drug specifically approved for treating breakthrough cancer pain. Fentanyl in OTF is absorbed across the oral mucosa but a considerable portion is swallowed and absorbed enterally. The effects of age on OTF pharmacokinetics and pharmacodynamics are unknown. This in-vestigation evaluated OTF disposition and clinical effects in older (60–75 yr) compared with younger (18–40 yr) volunteers. Methods: Healthy young (26 6 yr) and older (67 6 yr) volunteers (n 12 each) were studied in an Institutional Review Board approved protocol. They received OTF (10 g/kg). Plasma fentanyl and norfentanyl concentrations were deter-mined by mass spectrometry. Fentanyl effects were measured by dark-adapted pupil diameter and by subjective self-assess