Why isn't my beta blocker enough to treat my blood pressure?

Beta blockers like metoprolol (Lopressor, Toprol-XL) are not great medications for lowering blood pressure when used all by themselves. So, as the day goes on, and you eat and exert yourself physically, the metoprolol is just not strong enough to control your blood pressure. One option is to switch to another medication, such as a diuretic or an ACE inhibitor. If your doctor thinks you need the beta blocker for some other cardiac condition, adding a diuretic or ACE inhibitor to the beta blocker makes sense. In fact, combining low doses of medications that fight high blood pressure in different ways is probably a more effective way to do it than with a high dose of a single medication.