Zytiga with Cortisone instead of Prednisone? Health issues because of it?

Hello!  My dad is 78 and has been fighting prostate cancer for some time and had his prostate out 14 years ago.  His last medicine was Keto and he was taking that with 10mg of cortisone, 2 times a day.  This failed after about 7 months and his PSA actually tripled between psa checks (its 6.0 now or so), so they have moved him to Zytiga.  When they proscribed him the zytiga, the doctor did not change his steroid or even mention it.  I noticed the Zytiga insert states it needs to be taken with prednisone and immediately asked the nurse and she told me "it should be fine" as is.  His blood pressure went up about 3 weeks into taking Zytiga and he has been retaining fluid, so I called the doctors office.  The doctor that prescribed it is now on vacation and the PA told me that this doctor likes to use cortisone instead of prednisone and go against what is recommended.  So yesterday we checked his legs and he has pitting from fluid retention pretty bad and said he has chest tightness and is actually losing his voice.  He went in today to his general doctor and they thought it was the Zytiga causing it and not pneumonia or anything else.  I'm no doctor, but if I do the math, it seems like he's only getting half of the recommended steroid?  (Zytiga is taken with 5mg Pred 2x daily and he's getting 10mg cortisone 2x daily) Does anyone know if the symtoms he's having could be caused by taking cortisone instead of prednisone?  He's at his heart doctor now because his EKG came back abnormal also today.  I really appreciate ANY advice or thoughts you have.  Thanks, and thanks for all of the posts and support this forum gives.

Matt

So since the doctor is on vacation, he called into my dads heart doctor from his vacation and told him to completely stop taking zytiga AND cortisone...cold turkey. He won't get to see this doctor until he's back on Monday of next week. This was our last hope before Chemo and I'm not sure my dad will want to go into Chemo. Thanks for the reply and thats the same conclusion I came up with, he was getting less than half of the steroids he was suppose to be getting with Zytiga which may well have caused these side effect.

Hey Winter! He has a history of heart problems with a stent in place plus a history of high BP which was being controlled well with meds prior to Zytiga.  They scheduled his first follow up at 1 month from the new prescription being started which probably was too long.  I called them a week ago to let them know about his high blood pressure and fluid retention and specifically asked about the lower dose of steroid which goes against how it's suppose to be prescribed and they told me to take him to his heart doctor to figure it out.  He is taking this pre-chemo and his insurance approved it.  That being said after the excitement for him to start it, I'm not very happy with the support of his doctor and blowing off the side effects until he ultimately had to be taken off of it.  Zytiga seems really safe especially compared to Keto which he tolerated well. I've read nothing but good things of this medicine and there's so many promising medicines in the pipeline coming along that I hope I can get my dad to switch doctors so we can have the best possible outcome for him.  I'm hoping to talk him into a 4 hour trip to Memorial Sloan Kettering to be seen once we figure out his new heart problems.  Everything I've read says stopping steroids abruptly could cause problems and I hope it doesn't - and again he doesn't have a follow up appointment for this change but is suppose to call back on Monday when the doctor is back from vacation to make an appointment.  His psa was tripling on Keto before the switch.