I get brain fog with my afternoon dose sometimes, and weird sensation in my arms. I just recently replaced the middle of the day dose with nortriptylene 25 mg., gone is the brain fog so I'm down to 600mg x2. I take a second 25mg dose of nortriptylene at bedtime, fairly new to this drug, and so far have no problem with it. Of course theres a few other meds I take everyday too, but the ones I mentioned are strictly for PN. This isn't fun but it can be done, welcome aboard.