Assessment of the Effectiveness of Ethosuximide in the Treatment of Peripheral Neuropathic Pain.

Assessment of the Effectiveness of Ethosuximide in the Treatment of Peripheral Neuropathic Pain.

Currently, it is established that the voltage-gated calcium channels modulate pain perception due to an influence on the neuronal transmission and excitability. In the past, attention has focused on the modulation of high voltage activated calcium channel. More recently, scientific interest has proven to the low voltage activated calcium channel, also called T-type channels. The data from the literature show significant involvement of these channels in the physiology of nociception and pathophysiology of acute and chronic pain. Moreover, in several animal pain models (acute, neuropathic, inflammatory), T-type channels inhibition alleviates painful behaviours.

Analgesics treatments available in clinic are ineffective in some patients with chronic pain (neuropathic, inflammatory) and often induce deleterious side effects. Thus, the clinical use of selective inhibitors of T-type channels could not only help the development of new therapies for the treatment of neuropathic pain (prevalence = 5-8 %), but also have a pharmaco-economic impact due to the low selling price of their inhibitor currently available: Zarontin®.

The purpose of this study is to assess the effectiveness of ethosuximide (Zarontin®) on the pain symptoms and quality of life in patients with peripheral neuropathic pain compared to a control group.

This is a multicentre, parallel-group, double-blind, randomised clinical trial comparing ethosuximide and inactive control for the treatment of peripheral neuropathic pain, assessed by numerical rating scale and quality of life questionnaire.

Inclusion Criteria:

• Age ≥ 18 years
• Traumatic neuropathy or post-surgical (excluding amputations) with Neuropathic -Pain Diagnostic DN4 ≥ 4 positive and IASP criteria
• ENS pain ≥ 4
• ALT, AST, PAL, normal GGT, creatinine <133μmol / L, hematocrit> 38%, β-HCG
• Patients affiliated to the French Social Security
• Patients with free and informed consent has been obtained
• Peripheral neuropathic pain with Neuropathic Pain Diagnostic DN4 ≥ 4 positive

Exclusion Criteria:

• Pregnancy or breastfeeding
• Diabetic neuropathy, post-herpetic neuralgia, cancer or chemotherapy-induced,
• Patients with impaired glucose tolerance,
• Medical and surgical history incompatible with the study,
• History of renal disease and / or liver,
• Addiction to alcohol and / or drugs,
• Taking antiepileptic family carboxamides and ethosuximide
• Use of St. John's wort,
• Allergy succinimides (ethosuximide, methsuximide, phensuximide)
• Psychotic disorders,
• Patients with epilepsy,
• Patient exclusion period, or the total allowable compensation exceeded
• Patients undergoing a measure of legal protection (guardianship, supervision ...)
• Central neuropathic pain
• Other chronic pain (osteoarthritis, arthritis, fibromyalgia…) with intensity greater than neuropathic pain