Investigator listing can be found as an Appendix in the online version of this article.
Topiramate in painful diabetic polyneuropathy: findings from three double-blind placebo-controlled trials
Article first published online: 7 SEP 2004
Acta Neurologica Scandinavica
Volume 110, Issue 4, pages 221–231, October 2004
How to Cite
The Topiramate Diabetic Neuropathic Pain Study Group, Thienel, U., Neto, W., Schwabe, S. K. and Vijapurkar, U. (2004), Topiramate in painful diabetic polyneuropathy: findings from three double-blind placebo-controlled trials. Acta Neurologica Scandinavica, 110: 221–231. doi: 10.1111/j.1600-0404.2004.00338.x
- Issue published online: 7 SEP 2004
- Article first published online: 7 SEP 2004
- Accepted for publication June 21, 2004
- diabetic neuropathy;
- neuropathic pain
Objectives – To evaluate the efficacy and tolerability of topiramate in patients with painful diabetic polyneuropathy.
Materials and methods – Patients with moderate to extreme pain (0–4 Categorical Pain Scale score ≥ 2) were randomized to placebo or topiramate (100, 200, or 400 mg/day) in three similar double-blind trials. The primary efficacy analysis was pain reduction from final visit to baseline in the 100-mm Visual Analog Scale (VAS) for the intent-to-treat populations.
Results – After 18–22 weeks of double-blind treatment, pain reductions were numerically greater with topiramate in two studies but differences between topiramate and placebo in VAS scores or in the secondary efficacy endpoints did not reach statistical significance in any of the three studies. Across all studies, 24% of topiramate-treated patients and 8% of placebo-treated patients discontinued due to adverse events; groups did not differ in the occurrence of serious adverse events.
Conclusion – These studies did not find topiramate to be significantly more effective than placebo in reducing pain scores in patients with painful diabetic polyneuropathy. Several design features may have precluded the studies from having sufficient sensitivity to differentiate effective and ineffective treatments. The study design and results are instructive for other investigators designing future clinical studies in neuropathic pain.