May I suggest you consult a Naturopath, a physician who will be educated and knowledgeable about juice fasting and would be able to help you devise a routine that would/could accomodate your medication in a safe manner while fasting.
If you do not choose to consult a Naturopath, then I would suggest to modify your juice fast by slowing down the detox considerably by consuming a banana and/or an avocado, fresh raw fruits and veggies, in between your raw live juices. You would still benefit, though everything (weight loss, detox, healing, etc) will be slowed down.
Juicing on raw live juices are fantastic for normalizing blood pressure (as you know already) and rebalancing the body.
To fast on dead, bottled juices while you are taking such serious medication doesn't sound very healthy to me. You could harm yourself in the long term.