[Transcutaneous fentanyl].

Soon available in Europe, fentanyl transdermal system (Transdermal Therapeutic System: TTS fentanyl) is a new, easy and non invasive way for delivery of a strong opioid. Skin is not only a transit site for transdermal administered drugs, but is an active barrier and acts as a reservoir after removal of the delivery system. Use of transdermal fentanyl has first been studied for the treatment of postoperative pain. But the great latency of the kinetics of fentanyl by this way certainly moderates this indication. Latency is a much less important problem for chronic administration in cancer pain. This could be an interesting indication for TTS fentanyl. But there are still troubles in converting previous opioid therapy doses when initiating transdermal administration, and in controlling breakthrough pain, so common in cancer patients. Further clinical studies are needed to determine optimal conversion rules and elaborate guidelines for control of acute pain episodes with "rescue doses".