Hi, After going through your case there is likely possibility of cardiac arrhythmia (abnormal electrical activity of heart) that may be responsible for your episodes of passing out. For controlling heart rhythm and preventing cardiac arrhythmia you might have been prescribed metoprolol and not for blood pressure. For better advise I want to know- 1) Your age. 2) Presence of other comorbid conditions like diabetes. 3) Any other medicines other than metoprolol going on. Following investigations may be helpful in decision making- 1) ECG during period of passing out. 2) Resting ECG. 3) 2DEcho of heart. 4) Holter s monitoring and electrophysiological study of heart. 5) Complete blood count, Kidney & Liver function tests, serum electrolytes, calcium, magnesium, phosphorus. 6) Thyroid function test. 7) If nothing is significant in above mentioned test then there may be need for MRI brain with angiogram. From above test we can come to know about cause for your symptoms and accordingly appropriate decision cane be taken. Hope this may be helpful to you. If so do vote.