For anyone considering clonidine and/or hibiscus tea, please don't do it if you have low blood pressure. I think it will make your blood pressure worse and possibly exacerbate your MS via greater electrolyte imbalance. You might be able to follow my haphazard thinking at this link...a thread about ACTH (which clonidine suppresses) and interferons. general-discussion-f1/topic21861.html
I think if you have MS and low blood pressure, you may have been pushed into adrenal insufficiency and might be short on ACTH among other things. I really don't know though. You may have been short on aldosterone all along...the hpa-axis studies tend to focus on cortisol, not aldosterone.
I still think clonidine might be a possibility for people with normal to high blood pressure. I had normal and I had to go off clonidine after almost 2 months. My blood pressure went low. I'm hoping my hpa-axis corrected but won't know for a while.
If you want to try correcting hpa-axis w/o messing with aldosterone/bp, you could try zinc.http://link.springer.com/article/10.100 ... 43?LI=true
Or, the better path for people with low bp might be adrenal support supplements like vesta takes.