Is it true too much magnesium supplements along with a beta blocker can cause you to feel dizzy?reasoning behind this?

Beta blockers: Beta blockers can cause dizziness(usually lightheadedness) by either lowering the blood pressure too much or by slowing the heart rate too much. Excessive amounts of magnesium supplements can cause diarrhea which,if profuse, can cause weakness. Follow the directions or check with your physician or pharmacist for advice about dosage. In any event you should notify your Physician about your symptoms