Conditions: Low Back Pain Pain
Keywords: chronic pain low back pain D-cycloserine
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 41
Healthy volunteers: no

Brief summary:
Pre-clinical studies in rats suggest that D-cycloserine (DCS) is effective in the management of chronic neuropathic pain. This pilot study will attempt to determine the effect of D-cycloserine in the treatment of chronic low back pain. Other aims of this study are to determine the safety of D-cycloserine in the treatment of chronic low back pain and to determine which pain measurement scales are best at measuring the efficacy of treatment.

Detailed description:
Human brain imaging studies indicate that the medial prefrontal cortex activity can predict more than 80% of the variance of chronic back pain intensity. Therefore, the investigators have hypothesized that modulation of brain activity at this site should result in analgesia. D-cycloserine has been shown to potentiate conditioned fear extinction. Based on this the investigators hypothesize that chronic neuropathic pain (back pain with radiculopathy) is partially mediated or potentiated by decreased ability to extinguish the pain memory, which the investigators hypothesize to be mediated through reward/aversion brain circuitry, and specifically through medial prefrontal cortex. They have tested this idea in pre-clinical studies and demonstrated that rats with neuropathic pain show analgesia over the long-term when treated with D-cycloserine. In humans with chronic back pain, the investigators hypothesize that D-cycloserine will enhance extinction of back pain which in turn should result in reduced emotional relevance of the pain, that is reduced suffering. It is quite possible that the overall intensity of the back pain will be unaffected, however, the associated suffering will be significantly attenuated.

This will be a double-blind, randomized, parallel group escalating dose study comparing D-cycloserine twice a day (bid) with placebo bid in patients with chronic low back pain. Subjects meeting inclusion criteria will continue baseline medications and be treated for 12 weeks with study drug: 50 mg bid DCS or matching placebo for the first 4 weeks, then 100mg bid DCS or matching placebo for 4 weeks and finally 200mg bid DCS or matching placebo for 4 weeks. Assessments of efficacy and safety will be undertaken every 2 weeks using standard, validated instruments to evaluate change in pain, function, quality of life and adverse events.

Arms:
arm 1: D-cycloserine 50mg bid/100mg bid/200 mg bid arm 2: placebo

Interventions: intervention 1: D-cycloserine intervention 2: placebo
Intervention descriptions: intervention 1: D-cycloserine 50 mg bid; D-cycloserine 100 mg bid; D-cycloserine 200 mg bid intervention 2: placebo bid

Protocol document: