Transdermal fentanyl for the treatment of pain after major urological operations. A randomized double-blind comparison with placebo using intravenous patient-controlled analgesia.

Transdermal fentanyl 75 micrograms/h (Fentanyl-TTS) was compared with placebo in a randomized double-blind study in the early postoperative period, using 50 patients recovering from major urological operations. Analgesic efficacy was individually titrated with intravenous fentanyl by means of a PCA pump (demand dose 34 micrograms, lockout time 5 min). The test systems were applied 8 h before anaesthesia and were left in situ for 24 h. During the PCA period (18.2 h) patients with Fentanyl-TTS required significantly less additional fentanyl (0.48 vs 0.93 micrograms.kg-1.h-1) and reported less pain than patients in the placebo-group. Patient acceptance was high in both groups. Side-effects were of only minor intensity and did not differ between the two groups. In particular, there was no case of clinically relevant respiratory depression.