Intraspinal narcotic tolerance: preliminary experience with continuous bupivicaine HCL infusion via implanted infusion device.

Spinal opiate receptor tolerance is the major limitation of continuous intraspinal narcotic analgesia delivered by implanted reservoir pump. Six intractable pain patients receiving continuous epidural morphine were given trials of low dose bupivicaine HCL in order to assess the effects on implanted reservoir function, analgesia, and safety. Daily infusion of 2.6-18.8 mg bupivicaine HCL had no consistent effect on flow rates. Subjectively, three patients had at least partial relief of pain while their intraspinal morphine doses were weaned. No sympathectomy was appreciated at these doses. The future of continuous intraspinal analgesia might require further advances in implantable infusion pump technology to allow manipulation of both daily infusion doses and multiple intraspinal analgesics. Further study is needed to assess the safety and effectiveness of higher continuous intraspinal bupivicaine doses for chronic pain relief.