Is lopressor Tartrate a ACE or ARB?

Lopressor Tartrate, which contains the active ingredient metoprolol tartrate, is neither an ACE inhibitor nor an ARB. It is a beta-blocker, primarily used to treat high blood pressure and certain heart conditions. ACE inhibitors (Angiotensin-Converting Enzyme inhibitors) and ARBs (Angiotensin II Receptor Blockers) are different classes of medications that work on the renin-angiotensin system.