Merlo...YES, most definitely my BP was uncontrollably high when I was on prednisone. My doctor had me on three different blood pressure medications too and it still ran 216/110. I consider myself very fortunate that I never had a stroke! I knew it was really up there when I had pounding headache on top of my head. When I was young (I am now 66), my blood pressure was very low. As a matter of fact, my doctor always had a hard time getting a reading because it was so low. When I went through menopause at age 45 my blood pressure became higher and I was placed on Toprol xl. My blood pressure was very well controlled until I developed UP in 1998 at age 52 and was placed on prednisone. From 1998 until I had surgery in 2010, I had to be hospitalized four times for BP and twice for UP.
Prednisone can also increase your blood glucose levels. I developed type 2 diabetes while on it and had to take Medformin. 
I was able to taper off the prednisone completely by six weeks post op. My BP is very well controlled with the Toprol (130/66 this am) and I no longer have diabetes. I will forever have osteoporosis and have three back fractures.
Long story, I know, but beware of the hazzards of prednisone!