postherpetic neuralgia
"I experienced severe nerve pain following a second bout of shingles less than 3 months apart. During a 2 year period my doctors tried me on regular Gabapentin in combination with other medications - all with severe side effects and no relief from the constant pain and lack of a good night sleep.  I gained over 50 lbs as well.  My neurologist prescribed Horizant twice a day and my life changed almost over night!  I choose not to take it in combination with anything else other than 800 mg Ibuprofen when needed because concerns of past side effects. Eventhough my nerve pain has continued two years later and another bout of shingles I have been able to manage the pain with Horizant."