[Epidural opiates for relief of chronic pain (author's transl)].

Epidural opiate application was performed in 75 patients with chronic pain due to abdominal cancer. To reduce the risk of local infection, the epidural catheter was in part placed subcutaneously. Degree and duration of analgesia were determined after epidural morphine (with and without bupivacaine), pethidine or fentanyl. Hemodynamic and respiratory parameters were measured and side-effects were registered. The longest duration of analgesia was observed after epidural morphine. In long-term treatment there was a reduced efficiency and the frequency of daily injections increased, especially in those patients who already had received systemic opiates prior to the epidural opiate administration. This may be due to tolerance of the spinal receptors. A combination of epidural morphine with small doses of local anesthetics caused prolonged action and delayed the onset of tolerance. Besides slight influences on respiratory function, which may be referred to the initial period of systemic absorption, there were no relevant side-effects. Regarding certain precautions the epidural application of morphine may have advantages in comparison to systemic analgetics in treatment of chronic pain.