What can be an effect of discontinuing propranolol suddenly?

Discontinuing propranolol suddenly can lead to an increased risk of heart complications due to its role as a beta-blocker. Propranolol works by blocking beta-adrenergic receptors, which reduces heart rate and blood pressure. When a patient stops taking propranolol abruptly, particularly after long-term use, it can result in a rebound effect where the body's receptors become overly sensitive to catecholamines (like adrenaline). This may lead to an increase in heart rate, elevated blood pressure, and in some cases, more severe heart complications such as arrhythmias or angina.

This phenomenon underscores the importance of tapering off propranolol gradually under medical supervision to minimize the risk of these adverse effects. Unlike the other options, which do not directly relate to the physiological consequences of sudden discontinuation of this medication, the risk of heart complications specifically ties back to the pharmacological action of propranolol and the body's compensatory mechanisms.