POTS patient incredibly confused by experiences with hyoscyamine

I've started some rather lengthy discussions on here a while ago before I was officially diagnosed with POTS and was trying to figure out what my symptoms were, but for this one I'll spare you the extra details. Long story short, I'm a diagnosed POTS patient (a male one, which is unusual).

I don't know what sub-type of POTS I have, but, for what it's worth, it seems like, in my case, my blood pressure (unlike my heart rate) doesn't change much when I stand up. I also have never once passed out to my knowledge from my POTS (although I feel faint quite frequently), not even during my tilt table test when they gave me a nitroglycerin tablet to basically try to make me faint if I was going to do so. For most of the time I've had POTS, I'd say fatigue or lack of energy has been one of my most problematic symptoms. However, I've been exercising pretty religiously almost every day for months now, and it doesn't seem to worsen my fatigue; in fact, even if it often doesn't last long enough afterwards, I'd say it actually helps me have more energy sometimes. For that reason, it doesn't seem like my POTS is secondary to CFS/ME.

Now that I've given you that background info, what has me so confused is regarding the hyoscyamine I was just recently prescribed for my irritable bowel syndrome (which I was diagnosed with due to the stomachaches I used to get frequently around the same time my POTS started in early 2016). The prescription was given when I went in to talk about various digestive abnormalities I've had going on for quite a while (such as soft, loose, unusually colored stools that sometimes come on suddenly), so it was not prescribed for my POTS, although my primary care doctor was aware I had POTS when he prescribed it (and he also mentioned that I should be careful to keep my fluids and electrolytes up using PediaLite if I'm losing them through my bowel movements).

Here's where it gets weird. I looked up hyoscyamine, and it turns out that it's an anticholinergic drug, and it works by blocking the activity of acetylcholine and preventing the parasympathetic nervous system from affecting the digestive tract and other organs. My impression was that some POTS experts/researchers (Dr. Dianna Driscoll being one example) think that POTS may be related to too little acetylcholine and parasympathetic activity, not too much. Isn't that also why pyridostigmine is sometimes prescribed for POTS? In theory, then, one would think that, even if it helps with my IBS, hyoscyamine should make my POTS symptoms worse if it affects them at all.

I haven't taken the hyoscyamine much yet since it was only just prescribed, but, in practice, it seems like it's been the most noticeably helpful thing I've been prescribed since my POTS started in terms of how I feel subjectively, and it seems like any adverse side effects have been so minor that I can't be sure whether I'm actually noticing them or just imagining things. For instance, I took it shortly before going to the gym a few days ago and it felt like that workout went unusually well. It was easier to breathe correctly while exercising, for example, and I didn't seem to get as sweaty and tired out as I usually do. I was watching my heart rate during that workout, and, if it was elevated at all, it didn't seem to be by anything more than my heart rate varies on a day-to-day basis. Not only that, but I feel like I notice a surprisingly conspicuous improvement in my energy level whenever I take it in addition to making my digestive tract behave, and I've always thought the fatigue was a symptom of my POTS.

Anyway, this all seems like almost the opposite of what I would expect to happen. Can anyone else here make any sense of what might be going on?

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