Respiratory failure due to the combined effects of transdermal fentanyl and epidural bupivacaine/diamorphine following radical nephrectomy.

The transdermal therapeutic system (TTS) fentanyl has been designed for rate-controlled drug delivery. When the system is applied, a fentanyl depot concentrates in the upper skin layers. Plasma concentrations are not measurable until 2 hours after application, and it takes an 8-16 hr latency period until full clinical fentany effects are observed. Following removal, serum fentanyl concentrations decline gradually and fall to about 50% in approximately 16 hours. We report the case of a 77-year-old man with a history of severe arthritis, who was receiving transdermal fentanyl and developed respiratory failure after starting epidural diamorphine/bupivacaine for postoperative pain relief following radical nephrectomy.