Epidural morphine subsequent to epidural analgesia for postoperative pain prevention

Abstract

Current practice in treating postoperative pain put emphasis on "centrally acting analgetics rather then on interrupting of pain impulses before they reach sensorium" (2). Presence of the endogenous opioid peptides and identification of their receptors in the substantia gelatinosa (8, 10), where the first sensory integration occurs, suggested the possibility of inhibiting the pain impulses at the spinal cord level. There are reports of profound and longlasting analgesic effect of morphine, pethidin, fentanyl and endorphin when administered epidurally or intrathecally (1, 3, 12, 11, 7). Behar and others (4), in a clinical trial, treating various pain syndromes with epidurally applied morphine, described a short onset of analgesia, 3-5 min, the absence of side-effects and pain relief of long duration. Motor and autonomic nervous functions were. not altered and a relatively long analgesic effect of epidurally applied morphine contributed towards an increasing interest in this method over conventional ones. Husemeyer and others (4) reported failure of epidural morphine to relieve pain in labour.