It can take at least a week- if not 3 or 4, at each increase,
for s/e to subside.
How long have you been at 400? I would give it 3-4 weeks at 400.
If s/e persist, it may be time to try other meds that don't have
negative side effects.
It is a compromise tho. You will have to trade off the pain relief and the s/e until you find a med that's right for you. We're all different, and that's why over 75 meds are used to treat PN.(I have an .xls complete listing of the meds that have been mentioned on these boards over the last 5 years, as a reference)
I find a constant dose of tramadol (every 4-6 hrs) is necessary, along with the Lyrica (Neurontin before I switched) to keep both pain and symptoms under control. Most of us use a combination of meds to control PN pain and symptoms. No one drug alone seems to do the trick.