Kristian S. Fruge¹ and Jeffery D. Evans²

¹Pharmacy Practice Resident, Texas Tech University Health Sciences Center School of Pharmacy, Hendrick Medical Center, 1718 Pine St., Abilene, TX 79601, USA. ²Assistant Professor of Pharmacy Practice, The University of Louisiana at Monroe, 1725 Claiborne Avenue, Shreveport, LA 71103, USA.

Abstract

Objectives:  To provide background information on diabetic peripheral neuropathic pain (DPNP), current treatment options for DPNP, and information about lacosamide. To determine the safety and efficacy of lacosamide as a treatment option for DPNP.

Methods:  A literature search was performed in order to describe DPNP, locate pertinent information about lacosamide, and determine the safety and efficacy of lacosamide for the treatment of DPNP in various trials. A search was also performed to review the effects of other medications on DPNP for the education of the reader as well as to make a comparison to lacosamide.

Results:  DPNP is a common occurrence in patients with diabetes. Options for the treatment of DPNP include anti-depressants, anti-convulsants, opiates, and other alternative medications. One of the most recently studied drugs for DPNP is lacosamide, an anti-convulsant usually prescribed for the adjunct treatment of partial onset seizures. Three RCTs using lacosamide and an extension to one of the trials was found and reviewed. Rauck et al found that lacosamide titrated up to 400 mg divided twice daily to treat DPNP caused 60% of patients to have a significant decrease of 3.11 on the Likert Pain Scale as compared to 50.8% of patients in the placebo group having a decrease of 2.21 on the Likert Pain Scale from the beginning of treatment until conclusion of the trial. Shaibani et al performed an extension to the trial performed by Rauck et al and determined that the effects of lacosamide used for DPNP were maintained over a 2.5 year period. Wymer et al reproduced the results of the study done by Rauck et al by using 200 mg, 400 mg, and 600 mg of lacosamide divided twice daily and comparing them to placebo to see the difference in the Likert Pain Scale scores from the beginning of the trial to conclusion of the trial. The Likert Pain Scale differences were 1.8, 1.9, 2.5, and 2.0 for the placebo, 200 mg, 400 mg, and 600 mg dosage groups, respectively. In the 400 mg lacosamide daily group, 58% of subjects experienced a significant decrease in the Likert Pain Scale score. The 200 mg and 600 mg dosage groups showed no difference in the Likert Pain Scale scores. Ziegler et al studied the changes in pain scores from baseline to the last four weeks of maintenance therapy using lacosamide 400 mg and 600 mg versus placebo. No significant changes were seen in either group. The 400 mg and 600 mg groups lowered the pain scores −0.40 and −0.36 points below placebo, respectively. However, when broken into sections, the trial did show significant changes in pain scores. There were no significant differences in adverse effects across all trials using the 400 mg dose of lacosamide. No trials were found that compared lacosamide to any other drug for the treatment of DPNP.

Conclusion:  Mixed results do show that lacosamide has the potential to effectively and safely lower pain scale scores in individuals with DPNP. However, due to a lack of consistent results and comparison studies with more established and accepted treatments, lacosamide cannot be recommended first line.