Pain
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Randomized Controlled Trial Clinical Trial
Epidural clonidine analgesia for intractable cancer pain. The Epidural Clonidine Study Group.
Although the vast majority of patients with cancer pain receive effective analgesia from standard therapy, a few patients, particularly those with neuropathic pain, continue to experience severe pain despite large doses of systemic or intraspinal opioids. Animal studies suggest intraspinal alpha 2-adrenergic agonists may be effective in such cases. Eighty-five patients with severe cancer pain despite large doses of opioids or with therapy-limiting side effects from opioids were randomized to receive, in a double-blind manner, 30 micrograms/h epidural clonidine or placebo for 14 days, together with rescue epidural morphine. ⋯ Clonidine, but not placebo, decreased blood pressure and heart rate. Hypotension was considered a serious complication in 2 patients receiving clonidine and in 1 patient receiving placebo. This study confirms the findings from previous animal studies which showed the effective, potent analgesic properties of intraspinal alpha 2-adrenergic agonists and suggests that epidural clonidine may provide effective relief for intractable cancer pain, particular of the neuropathic type.