Benadryl is also something of an anti-emetic, and can be given at 1 mg per pound of
the dog's weight, but I doubt it will be very effective in the face of
this kind of
vomiting. Worth a try though.
Another thing that helps is calcium - lots of it. I was giving Chica 2 Tums a day during her last couple of months. The calcium binds to phosphorus which is deadly to those in renal failure.