She said that it lasted about one day and that mostly she felt like "gritting her teeth" and was very nervous. I am presently on 3 - 300mg capsules twice a day and 4 at night for back pain, rls and sciatica. Seems to be helping to some extent, mostly for the back pain and sciatica. But I am worried about the amount I am taking... Too much? Too little? More worried about too much than too little and then having withdrawals.