Long-term intrathecal infusion of drug combinations for chronic back and leg pain

Continuous intrathecal infusion of analgesic drugs by implantable pumps is recognized as an established treatment option for patients with chronic pai n resistant to oral or parenteral medication. Polyanalgesia, the simultaneo us use of more than one intrathecal analgesic drug, is practiced relatively often, but there an, only a few published clinical studies on intrathecal polyanalgesia for chronic nonmalignant pain. This pilot study represents a long-term evaluation of a treatment regimen consisting of intrathecal morph ine admixed with bupivacaine, clonidine, or midazolam in patients with chro nic nonmalignant bark and leg pain due to degenerative lumbar spinal diseas e. Twenty-six adult patients have been treated by intrathecal programmable Pump-controlled infusion of analgesic drugs and followed for up to 3.5 year s (27 +/- 11 months). Combination of morphine with a second drug was used i n 10 cases, morphine with 2 additional drugs in 12 cases, and morphine with 3 additional drugs in 4 cases. Mean daily doses at 24 months after pump im plantation were 6.2 +/- 2.8 mg for morphine, 2.5 +/- 1.5 mg for bupivacaine , 0.06 +/- 0.03 mg for clonidine, and 0.8 +/- 0.4 mg for midazolam. Ninetee n patients reported excellent or good long-term treatment results, 6 patien ts had sufficient results, and only I patient complained of poor therapeuti c efficacy. No long-term clinical side effects of intrathecal polyanalgesia . were noted. Mean morphine dose had to be increased from 1.2 mg at baselin e to 5.1 mg at 24 months due to tolerance development and disease progressi on. This experience suggests that intrathecal polyanalgesia employing morph ine combined with additional nonopioid drugs can have a favorable analgesic efficacy in patients with complex chronic pain of spinal origin, and lacks major drug-related complications. (C) US. Cancer Pain Relief Committee, 20 01.