Sufentanil citrate and morphine/bupivacaine as alternative agents in chronic epidural infusions for intractable non-cancer pain.

Intraspinal narcotic (usually intrathecal morphine) infusions with implanted pumps are increasingly used in patients with intractable chronic pain not caused by cancer. In some patients, pain control is difficult with infusions of morphine. Seven patients with diagnoses of arachnoiditis, epidural scarring, and/or vertebral body compression fracture were treated with alternative solutions in an epidural route. For maximal flexibility, Medtronic implanted programmable infusion pumps with catheters to T6-T10 were used, and pain was monitored by verbal pain scales. In three patients, epidural infusions of morphine in 0.5% bupivacaine (MS-MARC) resulted in little or no pain relief without significant side effects (e.g., headache, nausea, or vomiting). In these same patients, epidural infusions of sufentanil citrate resulted in pain scale reductions of 92%, 82%, and 40%, respectively, with no side effects. Four other patients found more effective pain relief when switched from initial sufentanil citrate infusions to MS-MARC. Pain scale reductions (with no side effects) were 92%, 76%, 59%, and 47% in these patients. Pain relief and minimal side effects with sufentanil citrate is theorized to result from its higher lipophilicity promoting local transdural diffusion to spinal cord and limiting upward diffusion to the brain stem. Sufentanil citrate is also advantageous for programmable pumps because it is 100 times more potent than morphine and therefore allows longer pump refill times and higher infusion doses. Although this study was done on a limited number of patients, sufentanil citrate and MS-MARC in epidural infusions using programmable infusion pumps for non-cancer patients provide significant alternative drug combinations and routes.