Just wanted to put this out there for those of you taking blood pressure medications. I recently led a group on an overnight on the AT in MA. Everything was going fine until the last 2 miles heading into Salisbury, when one of the members of the group named Paul started having trouble walking (calve pain, sore legs, low energy). Dehydration was suspected, and in the last 1/2 mile or so he could only take about 5 steps before needing to rest (with no pack!). We got Paul into town (that's right, no SPOT rescue)and fed him and gave him water and gatorade, and he felt better on the way home.
The next day I spoke to him briefly around noon and Paul said he felt better, but by 4pm he was admitted to the hospital with renal failure. Apparently the doctors say he created the "perfect storm" of stress from hiking, dehydration, and mixing blood pressure meds with vitamin I, which brought on his kidney failure. Here we are one month later and his kidneys have finally restarted. He gets his catherter out hopefully Tuesday, and he hasn't needed dialysis for 5 days.
If I had to place a bet before the trip who would have problems Paul would not have been on that list at all. He has run marathons and backpacked before, and is generally in good health. The biggest mistake he made (other than mixing meds) was to not tell anyone he was having a problem until it was too late.
I only put this out there so that others using blood pressure meds will check their particular prescription for drug interactions, as not all BP meds act this way.