Oral Ketamine Administration in Patients With Peripheral Neuropathic Pain

Nowadays, available drugs cannot always produce pain relief in patients with neuropathic pain disease. It is believed that drugs acting as antagonists of the N-methyl-D-aspartic acid (NMDA) receptor may have been efficient in the treatment of neuropathic pain disorders. Ketamine is the only NMDA receptor antagonist commercially available in France. Ketamine is usually administered intravenously for surgical anesthesia. The intravenous administration of ketamine will be difficult to manage in the treatment of chronic neuropathic pain. Some trials using oral ketamine for the treatment of neuropathic pain were conducted but results were heterogeneous. This may be explained by the different range of ketamine doses tested. The aim of this clinical trial is to identify a safe and an efficient dose of orally administrated ketamine for the treatment of peripheral neuropathic pain. The clinical trial will be conducted in Toulouse Hospital, France. This study is a randomized, double-blind, placebo-controlled trial. The study will be conducted using 4 parallel groups (three doses of ketamine versus placebo).