Propranolol is contraindicated in patients with which condition?

• A. Bronchial asthma
• B. Hypertension
• C. Diabetes
• D. Heart failure

Answer: (A)

Propranolol is a non-selective beta-adrenergic blocker that can adversely affect patients with bronchial asthma. It works by blocking both beta-1 and beta-2 adrenergic receptors, leading to decreased heart rate and cardiac output, as well as relaxation of airway smooth muscles. However, in patients with asthma, blocking the beta-2 receptors, which are primarily responsible for bronchodilation, can lead to bronchoconstriction. This could exacerbate asthma symptoms or lead to an acute asthma attack, making it contraindicated in patients with this condition.

In contrast, propranolol can be beneficial or is not contraindicated in the other conditions listed. Its use in hypertension is common as it helps to lower blood pressure, it may require caution in diabetes but is not outright contraindicated, and in certain cases, it can be used in heart failure under careful supervision.