A double-blind randomised comparison of the effects of epidural clonidine, lignocaine and the combination of clonidine and lignocaine in patients with chronic pain.

Twenty patients with chronic pain who previously had obtained analgesia from epidural clonidine and lignocaine agreed to participate in a double-blind crossover study of lumbar epidural clonidine (150 micrograms), lignocaine (40 mg) and the combination of clonidine (150 microgram) and lignocaine (40 mg), all drugs were given in a volume of 3 ml. There were 11 women and 9 men with a mean age 53 years (range: 23-78 years); 9 patients had low back and leg pain, 9 had neuropathic pain, 1 had pelvic pain and 1 Wegner's granulomatosis. Pain intensity and pain relief, as well as sensory and motor blockade, were assessed for 3 h following each injection.