Intraspinal therapy for the treatment of chronic pain: a review of the literature between 1990 and 2005 and suggested protocol for its rational and safe use.

The administration of intrathecal drugs has been shown to be efficacious in the treatment of both cancer pain and noncancer pain in patients who do not respond well to conventional treatment, in those who are unable to tolerate side-effects of opioids, and in those who constantly require significant increases in drug dosing. Although morphine represents the "drug of choice" for intrathecal administration, the use of alternative drugs (e.g., bupivacaine, clonidine, and hydromorphone) appears promising for intrathecal therapy of pain in patients who are unresponsive to morphine, those who cannot tolerate its side-effects, and those patients with neuropathic pain. This study analyzes results of studies published from 1990 to 2005 in order to evaluate the efficacy of intraspinal therapy.