If you have high blood pressure, get it treated. Risk of stress-induced complications are higher with long shifts and especially with a lack of sleep. Also, most blood pressure medicines are on the $4/30 or $10/90 day supply list, so the medications are cheap too.
I've only spent about 30 hours awake (no sleep) before, it wasn't too bad, but I'm bracing myself for facing what you're going to be doing in the future when in medical school and residency. My best tips are to try to eat healthy, drink water, and stay alert. Things like Spike, Stacker 2s, etc. are amphetamine prodrugs, the body metabolizes them into the active drug, they are bad for you in general but especially if you have high blood pressure.