I started with 100 mg of Gabapentin about 9 months ago and then to 300mg to 600 mg to 1200 mg. In each instance it will work for 3 days to 2 weeks and then not effective. At 1200 mg (6 months ago) my doc added 30 mg of Cybalta. That worked for a few weeks. Then my neurologist upped Gabapentin to 2400 mg. It worked really well for 2 months (no nighttime pain) but now it is a hit and miss proposition. I am not aware of any obvious side effects so far.