Chadhas: I could be wrong here and someone may come along to correct me but I believe in most instances if you are on Lupron or such that the usual dosage of Casodex is 50mg and if it is Casodex alone then the dosage is bumped up to 150mg or such. It appears your Dr. has a good understanding of things from what you have said so far. It would make perfect sense to see how your dad reacts to the medications he is already on before adding or subtracting more.
The Zometa infusions have a tendency to get easier the more they are adminstered but if they don't, ask the Dr. to slow down the IV drip this sometimes makes a big difference in how patients respond to it.
Good luck
David