It caused me to lose my short term memory for 3 months while taking it.
I couldn't remember anything and was in a brain fog like a bad dream.
Once off it, everything came back to 'normal'. It did not help my pain or Sx from PN. I never got to titrate up to the dose my doc was aiming for (400mg/day).
It should be titrated slowly in 25mg increments over a long period of time. I didn't like it. It did cause me to lose 5-10 lbs over 3 mos, though.