In a patient Kishore having hypertension, propranolol was given. Though the drug controlled hypertension, it reduced resting heart rate to 50/min. Which of the following β blockers can be used in this patient as an effective substitute which does not cause bradycardia ?

**Core Concept**
β blockers are a class of medications used to treat hypertension and other cardiovascular conditions. They work by blocking the effects of the hormone epinephrine (adrenaline) and by slowing the heart rate and reducing its workload. However, not all β blockers have the same effects on heart rate, with some being more likely to cause bradycardia (slow heart rate) than others.

**Why the Correct Answer is Right**
Carvedilol is a non-selective β blocker, but it has a unique property that makes it less likely to cause bradycardia. Carvedilol has a high degree of α1 adrenergic receptor blockade, which helps to counteract the reflex tachycardia that can occur with β blockade. This makes it an effective substitute for propranolol in patients who develop bradycardia. Additionally, carvedilol has vasodilatory properties that can help to control blood pressure.

**Why Each Wrong Option is Incorrect**
**Option A:** Metoprolol is a selective β1 blocker, which means it primarily affects the heart rate and has a higher risk of causing bradycardia. It is not a good substitute for propranolol in this patient.
**Option B:** Atenolol is another selective β1 blocker that can cause bradycardia, just like metoprolol. It is not a suitable substitute for propranolol in this case.
**Option C:** Bisoprolol is also a selective β1 blocker that can cause bradycardia. It is not a good substitute for propranolol in this patient.

**Clinical Pearl / High-Yield Fact**
When choosing a β blocker substitute, consider the specific properties of the medication, such as its selectivity for β1 or β2 receptors, and its effects on α1 adrenergic receptors. Carvedilol's unique properties make it a good option for patients who develop bradycardia with propranolol.

**Correct Answer:** C. Carvedilol.

✓ Correct Answer: A. Pindolol