Effectiveness between Duloxetine and Pregabalin for the Management of Neuropathic Chronic Low Back Pain

Abstract

Background: Chronic low back pain has as a mixture of nociceptive and neuropathic component. This neuropathic component is often overlooked during management which increases the sufferings of patients. Prevalence of neuropathic pain is quite high and approximately 37% of chronic low back patients suffer from predominantly neuropathic pain. Treatment of neuropathic component of low back pain remains challenging and multiple modalities of treatments have been tried but not all of them are satisfactory. Among these, duloxetine and pregabalin have been shown to be promising in treatment of various neuropathic syndromes, but there is no direct comparative study between these two drugs in patients with back pain with neuropathic component. Objective of this study was to compare the effcetiveness between duloxetine and pregabalin which one reduce the pain and improve quality of life better.
Methods: This is a prospective, observational study. Chronic low back pain patients with neuropathic components were recruited according to inclusion and exclusion criteria. Pain was measured by visual analog scale and neuropathic component measured by painDETECT questionnaire score. Patients were randomly assigned to either duloxetine or pregabalin group. Both drugs were initiated with their lowest dose. Duloxetine was started with 20mg/day with optional up titration to 60mg/day (20mg, weekly increments) and pregabalin was started with 50mg/day with optional up titration to 300mg/day (50mg weekly increments) for six weeks. A fixed dose combination of paracetamol and tramadol (325mg + 37.5mg) was used as rescue medication for breakthrough pain. Follow up were carried out weekly by face to face visits or over phone. At week four and six, additional assessment of patients’ quality of life was assessed by SF-36. The primary outcome parameter was mean VAS score and quality of life improvement by assessing SF-36 was secondary outcome parameter.
Results: Out of 80 patients enrolled, 62 completed trial, eight patients in duloxetine and ten patients in pregabalin group dropped out. In this study, a significant reduction of pain intensity was observed with both Duloxetine and Pregabalin compared with their baseline values, but there was no statistically significant difference between the two treatments. The SF-36 score at the end of each treatment phase was significantly improved with both treatments. But when comparing in between two groups, the changes of mean SF-36 score was not significant as well.
Conclusion: Both duloxetine and pregabalin are well-tolerated having good safety profiles. Further clinical trials with long term follow up are needed to determine their long term effect.