Before administering Corgard (nadolol), the nurse should assess which of the following?

Before administering Corgard (nadolol), it is crucial to assess the patient's heart rate. Nadolol is a non-selective beta-blocker that works by blocking beta-adrenergic receptors, which can lead to a decrease in heart rate and blood pressure. Monitoring the heart rate helps ensure that the patient's heart rate is within a safe range before starting the medication, as nadolol can significantly lower the heart rate. If the heart rate is too low, administering the medication could lead to bradycardia, which can be dangerous.

Urine output, serum potassium levels, and weight are also important assessments in the overall management of a hypertensive patient but are not specifically required before the administration of nadolol. While changes in kidney function can be relevant to heart health, they are not the immediate concerns that need to be addressed prior to administering this medication. Additionally, monitoring serum potassium levels can be more relevant in the context of certain other antihypertensive medications, and weight can be more relevant for assessing fluid status rather than a direct contraindication for administering nadolol.