What finding would indicate a serious complication in a patient taking propranolol?

Audible expiratory wheezes would indicate a serious complication in a patient taking propranolol, as this medication is a non-selective beta-blocker that can potentially cause bronchospasm. Propranolol may block beta-2 adrenergic receptors in the lungs, which are responsible for bronchodilation. This can lead to constriction of the airways, resulting in wheezing or difficulty breathing, particularly in patients with a history of asthma or chronic obstructive pulmonary disease (COPD). If a patient experiences audible wheezing, it signals that the airway is constricted to a level that could compromise oxygenation and warrant immediate medical attention.

In contrast, a decrease in blood pressure and resting heart rate are common pharmacological effects of propranolol since it reduces cardiac output and heart rate. While these changes can be concerning if they are extreme or lead to symptoms, they do not necessarily indicate a serious complication. Insomnia can occur as a side effect but is less likely to suggest a severe or acute issue compared to respiratory complications. Therefore, wheezing is a critical sign that necessitates careful evaluation of the patient’s respiratory status while on propranolol.