Propranolol, as a beta-blocker, can increase airway resistance and potentially lead to bronchospasms in patients with conditions like chronic obstructive pulmonary disease (COPD) or asthma. These medications work by blocking beta-adrenergic receptors, which can result in constriction of the bronchial muscles. Therefore, it is essential to monitor patients closely when they are prescribed this medication to avoid any adverse respiratory effects.