Tramadol relieves pain and allodynia in polyneuropathy: a randomised, double-blind, controlled trial

Abstract

It is generally believed that opioids relieve neuropathic pain less effectively than nociceptive pain and that they have no effect on some of the key characteristics of neuropathic pain such as touch-evoked pain (allodynia). Tramadol is an analgesic drug acting directly on opioid receptors and indirectly on monoaminergic receptor systems. The aim of this trial was to determine whether tramadol relieved painful polyneuropathy and reduced allodynia. The study design was randomised, double-blind, placebo-controlled and cross-over. After baseline observations, 45 patients were assigned to one of the two treatment sequences. The dose of tramadol slow-release tablets was titrated to at least 200 mg/day and at highest 400 mg/day. During the two treatment periods of 4 weeks duration, patients rated pain, paraesthesia and touch-evoked pain by use of 0-10 point numeric rating scales. Mechanical allodynia induced by stimulation with an electronic toothbrush was rated at the end of each treatment period with a similar scale. Thirty-four patients completed the study. Their ratings for pain (median 4 vs. 6, P=0.001), paraesthesia (4 vs. 6, P=0.001) and touch-evoked pain (3 vs. 5, P<0.001) were lower on tramadol than on placebo, as were their ratings of allodynia (0 vs. 4, P=0.012). The number needed to treat to obtain one patient with >/=50% pain relief was 4.3 (95% confidence interval 2.4-20). It is concluded that tramadol appears to relieve both ongoing pain symptoms and the key neuropathic pain feature allodynia in polyneuropathy.

Chronic Pain and the Emotional Brain: Specific Brain Activity Associated with Spontaneous Fluctuations of Intensity of Chronic Back Pain

“…Chronic pain is often associated with spontaneous pain (pain in the absence of external stimuli), as well as changes in sensitivity to various somatosensory stimuli (Tasker et al, 1991;Clauw et al, 1999;Sindrup et al, 1999;Birklein et al, 2000;Dworkin, 2002). Approximately 10% of adults have severe chronic pain (Harstall and Ospina, 2003) and CBP is the largest contributor to this population (Atkinson, 2004).…”

Trends in opioid use for chronic neuropathic pain: a survey of patients pursuing enrollment in clinical trials

“…[7][8][9] Mu-receptor opioid agonists have been shown to reduce pain in a number of preclinical neuropathic pain models. [10][11][12] In humans, several randomized controlled trials have demonstrated that opioids reduce pain intensity, [13][14][15] and furthermore, decrease neuropathic pain-related disability. 16 Despite evidence of safety and efficacy in acute and cancer pain, studies have shown that physician and patient concerns about addiction and other adverse effects continue to be, often unwarranted, barriers to pain management in these settings.…”

Static mechanical allodynia (SMA) is a paradoxical painful hypo-aesthesia: Observations derived from neuropathic pain patients treated with somatosensory rehabilitation

“…As outlined in the Introduction, mechanical allodynia emphasizes its central sensitization, in particular in the dorsal root ganglion or in the dorsal horn (e.g., Woolf 1983;Hendry et al 1999;Mannion et al 1999;Sindrup et al 1999;Ji and Woolf 2001;Ji et al 2003;Sukhotinsky et al 2004;Devor 2006). The statement ''The static mechanical allodynia is a paradoxical painful hypoaesthesia'' does not contest the most likely central component of post-injury pain hypersensitivity (Woolf 1983).…”