ABSTRACT
The discovery of the 1970s, that morphine acts on the spinal cord, opened a new field of neuropharmacological inquiry and exploration of the greatest analgesic power of intraspinal narcotics. However not only hydrophilic and poorly lipid-soluble drugs such as morphine may be expected to travel slowly to pass out of the CSF into the lipid tissues of the neuraxis but also many adverse side-effects such as respiratory depression, urinary retention, pruritus,nausea and vomiting may be expected to develop in the morphine treated patients. In contrast to morphine, highly lipid-soluble narcotics such as fentanyl pass relatively freely between the dura and pia-arachnoid, rapid onset of action and fewer adverse effects may be expected to develop in the fentanyl-treated patients. To assess the clinical usefulness of epidural administration of fentanyl rather than morphine, we compared the onset and duration of analgesic action, self-satisfactory of analgesia and adverse side-effects between morphine and fentanyl treated 27 surgical patients. The results were as follows: 1) The onset time of analgesia in the epidurally fentanyl 50 ug treated group (F50 group) and 100 ug treated group (F100 group), 12+/-3 and 9+/-3 min respectively, were significantly shortened as compared with those in the morphine 5 mg treated group (morphine group), 21+/-2 min (p<0.05). 2) The duration of analgesic action in the F50 and F100 groups, 2.58+/-0.39 and 5.43+/-1.33 hours respectively, were significantly shortened as compared with morphine group, 14.30+/-2.16 (p<0.05). 3) Among 9 morphine treated patients, 8 patients feeled excellent or good analgesia. Also 9 of 10 fentanyl 50 ug treated and 7 of 8 fentanyl 100 ug treated patients feeled excellent or good analgesia. 4) Major complications in the morphine group were urinary retention 4 cases, nausea and vomiting 4 cases and pruritus 3 cases. Whereas only 1 patient in the F100 group complained of nausea and vomiting.