Gaba makes me feel weird, tingly is the best way to describe it. I don't use it because of that.

For back and pain caused by sciatica - you might see if an epidural is available. Do you know what is causing it? Unless it's a ruptured disc, it is treatable, or solves on its own. Stenosis and scoliosis could also be problems. Exercises to strengthen the core muscles should help. My lumbar spine is absolutely shot but I have a very strong core.