Which of the following drugs is categorized as a beta blocker?

Both Pindolol and Penbutolol are classified as beta blockers, which are a group of medications that primarily work by blocking the effects of the hormone epinephrine, also known as adrenaline. This action helps to reduce heart rate, decrease blood pressure, and minimize strain on the heart.

Pindolol is a non-selective beta blocker, which means it affects both beta-1 and beta-2 adrenergic receptors, thus influencing heart rate and blood vessel dilation. It is often used to treat hypertension and certain heart conditions.

Penbutolol is also classified as a non-selective beta blocker with similar therapeutic uses. By blocking the beta receptors, both pindolol and penbutolol contribute to reducing heart workload and controlling blood pressure.

Nadolol, while another type of beta blocker, is not included in the correct answer because the question specifies identifying both Pindolol and Penbutolol as beta blockers. Therefore, the option indicating both Pindolol and Penbutolol accurately captures the essence of beta blockers in this question.