A preliminary study of long-term epidural morphine for cancer pain via a subcutaneously implanted reservoir

A series of 252 patients with terminal cancer (mostly with bony metastases) were treated with epidural morphine. Results were good to excellent pain relief in 85% of patients, but those with malignant growths above the neck showed relatively poor response. For those who survived more than 3 months, the daily morphine requirement increased progressively from 3.5 +/- 0.6 mg to 19.5 +/- 5.3 mg. Drug tolerance developed but no signs of addiction were noted. Respiratory depression was detected in 2 cases due to negligence but resolved uneventfully. No infection of the central nervous system was seen. Systemic reactions were mild and transient. The major drawbacks were catheter failure which required reinsertion, and sharp pain during injection in the later stages of therapy. Despite the side-effects, percutaneous epidural morphine is a useful treatment modality of pain control in cancer patients because it is readily available, safe and not too expensive.