Question

In which of the following conditions should propranolol NOT be used?

• A. Asthma
• B. Panic attack
• C. Premature ventricular contractions (PVCs)
• D. Hypertrophic cardiomyopathy

Hint:

Non-selective beta blockade removes bronchodilator tone and can trigger bronchospasm, so propranolol is avoided in asthma.

Answer 1

The Correct Option is A

Step 1: Recall what propranolol does.
Propranolol is a non-selective beta blocker, meaning it blocks both beta-1 receptors (mainly in the heart) and beta-2 receptors (mainly in the smooth muscle of the airways and blood vessels).

Step 2: Explain the effect of beta-2 blockade on the airway.
Beta-2 receptors in bronchial smooth muscle normally cause bronchodilation when stimulated. Blocking them with a non-selective drug like propranolol removes this protective bronchodilator tone and can trigger bronchospasm, which is dangerous in a patient with asthma. This is why propranolol (and other non-selective beta blockers) is contraindicated in asthma.

Step 3: Check the other conditions.
In panic attacks, beta blockers like propranolol are actually used to control the physical symptoms of anxiety, such as tremor and palpitations. In PVCs, beta blockers can suppress the abnormal ectopic beats by reducing sympathetic drive to the heart. In hypertrophic cardiomyopathy, beta blockers reduce the force and rate of contraction, which relieves the left ventricular outflow obstruction, and are first line treatment.

Step 4: Final conclusion.
Among the choices, propranolol is helpful or standard treatment in panic attack, PVCs, and hypertrophic cardiomyopathy, but it is harmful in asthma because of bronchospasm risk.
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