Which medication is NOT a beta blocker?

Lisinopril is the medication in this list that does not belong to the beta blocker class. Instead, it is classified as an angiotensin-converting enzyme (ACE) inhibitor. ACE inhibitors are primarily used to treat hypertension and heart failure by relaxing blood vessels and reducing blood volume.

On the other hand, the other medications mentioned—Atenolol, Metoprolol, and Propranolol—are all beta blockers. Beta blockers work by blocking the effects of adrenaline on the beta-adrenergic receptors, which helps to lower heart rate, blood pressure, and reduces the heart's workload. Therefore, identifying lisinopril as the medication that is not a beta blocker is essential for understanding the different classes of medications used to manage cardiovascular conditions.