11. Concomitant use of antiepileptic drugs, non-steroidal anti-inflammatory drugs (except cardiac preventive acetylsalicylic acid), opioids, benzodiazepines, muscle relaxants, dextromethorphan, tramadol, topical lidocaine, topical capsaicin, and selective norepinephrine reuptake inhibitors. Subjects are allowed to enter with a maximum of 1 allowed analgesic medication for neuropathic pain, which mus be non-opioid and non-sedative and have been taken for at least 1 month (30 days) prior to Visit 1. Tricyclic antidepressants may be continued if designated as the single analgesic medication for the treatment of pain.