This trial was the follow-on trial to a preceeding double-blind, placebo controlled trial which included patients with at least moderate pain due to postherpetic neuralgia. It was conducted at six sites in Germany and has been clinically finalized. The patients had successfully completed the above mentioned trial in postherpetic neuralgia and, in the investigator's opinion, would benefit from long-term administration of Lacosamide. After a 1-week run-in phase the patients were uptitrated to their optimal dose and then continued into the maintenance phase. Dose adjustments were allowed throughout the trial.The change in pain was measured daily as well as interference of pain with sleep and general activity. As per protocol this trial was terminated after two years of treatment.

Inclusion Criteria:

• Postherpetic Neuralgia

Exclusion Criteria:

• Does not benefit from long term treatment