Barry, ask your neph for Proamatine (generic -Midodrine), but first see if they can't give you a saline bolus before taken you off and maybe some chips to eat. If that doesnt bring it up, then have neph prescribe Midodrine tabs. Hubby use to have this problem when in-center and when nothing else worked she prescribe Midodrine. That brought his up.
If I recall, he continually had to take them just before Dialysis Incenter. It helped somewhat. But since he does it at home, he hardly ever has to take meds anymore, except the binders & occasional PTH meds.
Let us know how it goes,
God Bless,
lmunchkin