Analgesic efficacy and tolerability of flupirtine vs. tramadol in patients with subacute low back pain: a double-blind multicentre trial

ABSTRACT

Objective: To assess the efficacy and tolerability of flupirtine in comparison with tramadol for the treatment of moderate to severe subacute low back pain (LBP).

Design and methods: In this randomised, double-blind, parallel-group trial, 209 LBP patients, aged 18–65 years, were orally treated with flupirtine 100 mg (n = 105) vs. tramadol 50 mg (n = 104), both three times daily for 5–7days.

Main outcome measures: Patient assessment of pain intensity after 5–7 days (primary); physicians’ global assessment of improvement in pain and functional capacity; adverse events.

Results: Flupirtine showed an overall pain-relieving efficacy comparable to tramadol. Mean LBP intensity after end of treatment dropped from 6.8 (95% CI: 6.5–7.0) to 2.8 (95% CI: 2.3–3.1) for flupirtine and from 6.9 (95% CI: 6.6–7.1) to 3.0 (95% CI: 2.6–3.4) for tramadol, corresponding to pain relief rates of 57% (95% CI: 51–63%) and 56% (95% CI: 50–62%) respectively (p = 0.796), indicating non-inferiority of flupirtine. All other efficacy endpoints supported equivalent efficacy. Adverse events (AEs) occurred significantly less in patients after flupirtine (33%) vs. tramadol (49%) (p = 0.02) and both the respective severity grading and the AE-related dropout rates were significantly lower after flupirtine than after tramadol (1% vs. 15%, p < 0.001).

Conclusion: Flupirtine 100 mg three times daily was associated with a reduction in pain and improvements in functional capacity equivalent to that observed with tramadol 50 mg three times daily, and was better tolerated, when administered to patients with subacute back pain for one week. The limitations of this study were the lack of a placebo control and the short (7-day) duration of the study.

Key words: :

• Flupirtine
• Tramadol
• Low back pain
• Subacute
• Disability
• Treatment

Acknowledgements

Declaration of interest: This study was supported by a study grant from Pliva Pharmaceutical Industry Inc., Beijing, China; the publication of the article was sponsored by AWD-pharma GmbH & Co. KG, Radebeul, Germany: a subsidiary of Pliva Inc., Croatia, and a member of the Barr Group. C.L., J.N., M.L. and Z.W. all received research grants from Pliva Inc. M.G. is an employee of Pliva Inc., Zagreb, Croatia. B.T. is an employee of AWD.pharma GmbH & Co. KG, Radebeul, Germany. M.A.U. is a scientific consultant for Pliva Inc., Zagreb, Croatia and AWD.pharma GmbH & Co. KG. The article was prepared in keeping with the ICMJE uniform requirements, and the authors take full responsibility for the contents of this article.

The authors would like to thank Dr. Gerhard H. Mueller-Schwefe, President of the German Pain Society, for his fruitful discussion of the data obtained during this study.

83 patients were enrolled at Beijing University First Hospital (Li Chunde), 59 patients at Xuanwu Hospital of Capital University of Medical Sciences (Ni Jiaxiang), 37 at Xijing Hospital of the Fourth Military Medical University (Li Mingquan), and 30 at Youyi Hospital of Capital University of Medical Sciences (Wang Zhiyi); all sites were in Beijing, China. Monitoring, data management and statistical analysis were performed by MedSept, Beijing, China and the Institute for Quality Assurance in Pain Therapy and Palliative Care, Nürnberg, Germany.

Notes

* These results were presented at the 19th German interdisciplinary pain and palliative congress, Frankfurt, Germany, 6–8 March 2008