Which of the following is a nonselective beta blocker?

• A. Atenolol
• B. Metoprolol
• C. Propranolol
• D. Carvedilol

Answer: (C)

Propranolol is categorized as a nonselective beta blocker because it inhibits both beta-1 and beta-2 adrenergic receptors throughout the body. This characteristic allows it to be effective in treating a variety of conditions, including hypertension, anxiety, and certain types of tremors. The nonselective nature means it can affect the heart (beta-1 effects causing a decrease in heart rate and contractility) as well as other organs and tissues (beta-2 effects which can cause bronchial dilation among other actions).

Atenolol and Metoprolol are both selective beta-1 blockers, primarily affecting cardiac tissues and generally having a more favorable side effect profile in patients with respiratory issues. Carvedilol, while it does have some beta-blocking activity, is more widely recognized as a non-selective alpha/beta blocker due to its additional effects on alpha receptors, making it distinct from pure beta-blockers like Propranolol.