I'm sure the Doctor is giving you Metoprolol to stabilize your heart rate. It is a beta blocker most often taken for high blood pressure. It is often given for palpitations or just to keep your heart from over working. I have taken Metoprolol and it can cause fatique because it is keeping your heartrate from increasing when it would normally need to under exertion.
I have Baroreflex failure caused by Radiation from cancer treatment. I have both high and low blood pressure because the baroreflex sensors in my carotid arteries that regulate you pressuree no longer work.
When my symptoms were mostly low pressure they were giving me Midodrine to raise my pressure. Make sure you are well hydrated because poor hydration can also cause low blood pressure.
I have pressures that will be 180/100 and within 30 minutes it can go low sometimes as low 55/35. I have found that staying hydrated is absolutely essential for me to function at all.
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