Benefit from and tolerance to continuous intrathecal infusion of morphine for intractable cancer pain.

A patient with painful bilateral metastatic lumbosacral plexopathy from cervical cancer was treated with levorphanol tartrate (Levo-Dromoran), 4 mg orally every 4 hours, with poor pain relief. A lumbar subarachnoid catheter was then placed percutaneously. A bolus of 1 mg of morphine gave complete pain relief for 17 hours. Over the next week, the dose requirement increased to 10 mg/day, infused by an external pump. A permanently implantable infusion pump with a 50-cc drug chamber and flow rate of 3.4 cc/day was placed in the abdomen and attached to the lumbar subarachnoid catheter. The pump was refilled by percutaneous injection. Morphine was infused continuously at 15 mg/day, affording the patient increased mobility and no pain for 7 days. When the pain returned, the morphine dose was increased to 17.5 mg/day, and the patient was allowed to take oral Levo-Dromoran for pain. The intrathecal morphine dose was constant within 2-week periods, but was increased from 17.5 to 96 mg/day because of inadequate pain relief. Oral Levo-Dromoran intake averaged 3.4 mg/day. Levo-Dromoran intake was less during the 1st week of each 2-week cycle than the last week (mean 15.0 versus 38.0 mg/wk, p less than 0.05). No sedation or respiratory depression was seen.