There are 4 people on one side of my family with CRPS and we all take Gabapentin. Our doses vary wildly. Two take more than 2000mg a day. I take 600mg in the morning and 600 at night, which is, according to my doctor, a rather low dose for what we have. If the dose you're on isn't working, I am sure your doctor can increase it, if the med. is helping you.
I didn't like Gabapentin, or at least thought I didn't, so my doctor, over the course of a couple years, tried many of it's "cousin" type drugs on me (ones that would accomplish what Gabapentin did, but maybe not make me so sleepy). After trying many "cousin" meds which gave me other worse symptoms or just plain didn't work as well, I went back to Gabapentin and found a dose I could function with. My relatives can take a lot more of it than I. So, I established that it's the best (at least for all in my family) in that category, and that the dose is more based on what is needed, person to person, to accomplish the needed effect.
I hope my experience with this medication will help you some. My dad also took it when he had a specific bad injury, and he called it a lifesaver. He isn't taking it anymore, but raved about it when he took it.