FENTANYL-TTS FOR POSTOPERATIVE PAIN TREATMENT - A NEW ALTERNATIVE

Treatment of postoperative pain is often insufficient. It normally con sists of systemic application of an analgesic drug or a regional techn ique of analgesia. Fentanyl-TTS may be a new approach for postoperativ e pain therapy. Fentanyl is incorporated into a transdermal system; af ter application to the skin continuous release of therapeutic doses is achieved for a period of 72 h. Serum peak levels are obtained 8-16 h after application; the serum half-life is about 16-21 h because of the dermal depot. Fentanyl-TTS was administered in several clinical studi es for therapy of postoperative pain. The efficacy of this new form of application could be demonstrated. For the first 12 h the patients ne eded supplementary doses of analgesic drugs in the same range as the p lacebo groups because of the lag time of fentanyl-TTS. In the followin g 12 h the need for supplementary analgesics was significantly reduced . After removal of the patch, the need for analgesics was still reduce d for 12 h. In 21 of 341 patients respiratory depression occurred unde r therapy with fentanyl-TTS; no respiratory depression was observed in the placebo groups. Thus, respiratory depression might occur in up to 9% of postoperative patients treated with fentanyl-TTS. Other adverse effects were nausea (62%), vomiting (26%), sedation (22%), urinary re tention (11%), headache (5%), and dizziness (8%). Local reactions unde r the patch were erythema (39%) or pruritus (9%). These phemonena disa ppeared within a few hours. The pharmacokinetics of fentanyl-TTS have two major drawbacks: during the first 12-15 h the patients need supple mentary analgesics, usually opioids. Side effects persist for a long t ime after removal due to the long serum half-life. With conventional m ethods of pain therapy, which may be titrated much more easily, the ri sk of respiratory depression is minimal. From the results of the clini cal studies, the safety and efficacy of fentanyl-TTS have not been dem onstrated sufficiently. The use of an analgesic method that can be mor e closely adapted to the individual needs of the patient might be a be tter alternative. However, fentanyl-TTS may become an option in the th erapy of chronic pain in patients needing constant opioid medication w ho are unable to get sufficient pain relief by enterally administered opioids due to their malignancy (i.e., carcinoma of the mouth or face or gastrointestinal tract obstruction.