What is an adverse effect commonly associated with beta-blockers?

Beta-blockers are a class of medications primarily used to manage cardiovascular conditions, such as hypertension, heart failure, and arrhythmias. One of the well-known adverse effects of beta-blockers is bradycardia, which refers to a slower than normal heart rate. This occurs because beta-blockers work by blocking the action of adrenaline on β-adrenergic receptors in the heart, leading to a decrease in heart rate and cardiac output. While a lower heart rate can be therapeutic in many cases, it can also become an undesirable effect, particularly if it falls below a certain threshold, leading to symptoms such as dizziness, fatigue, or fainting.

The other options listed are either not adverse effects associated with beta-blockers or are not typical. Hypertension, for instance, is often the condition that beta-blockers aim to treat, while constipation is not a well-documented side effect. Dry mouth may occur with certain medications but is not prominently associated with beta-blockers. Thus, bradycardia stands out as a significant and common adverse effect due to the mechanism of action of beta-blockers.