Transdermal fentanyl in children with cancer pain: Feasibility, tolerability, and pharmacokinetic correlates

Objectives: (1) To assess the feasibility and tolerability of the therapeut ic transdermal fentanyl system (TTS-fentanyl) by using a clinical protocol developed for children with cancer pain. (2) To estimate the pediatric phar macokinetic parameters of TTS-fentanyl. Methods: The drug was administered in open-label fashion; and measures of a nalgesia, side effects, and skin changes were obtained for a minimum of 2 d oses (6 treatment days). Blood specimens were analyzed for plasma fentanyl concentrations. The pharmacokinetics of TTS-fentanyl were estimated by usin g a mixed effect modeling approach. Results: Treatment was well tolerated. Ten of the 11 patients who completed the 2 doses continued treatment with TTS-fentanyl. The duration of treatme nt ranged from 6 to 275 days. The time to reach peak plasma concentration r anged from 18 hours to >66 hours in patients receiving the 25 mu g/h patch. Compared with published pharmacokinetic data from adults, the mean clearan ce and volume of distribution of transdermal fentanyl were the same, but th e variability was less. Conclusions: Treatment of children with TTS-fentanyl is feasible and well t olerated and yields fentanyl pharmacokinetic parameter estimates similar to those for adults. A larger study is required to confirm these findings and further test the clinical protocol.