A nurse is reviewing the medication administration record of a client who takes atenolol PO and applies a nitroglycerin transdermal patch daily. For which of the following interactions should the nurse monitor this client?

A. Thrombocytopenia: Neither atenolol nor nitroglycerin is commonly associated with thrombocytopenia. This is not the primary concern when these two medications are used together. B. Dry cough: A dry cough is a known side effect of ACE inhibitors (e.g., enalapril), but it is not commonly associated with atenolol or nitroglycerin. C. Hypotension: Both atenolol (a beta-blocker) and nitroglycerin (a vasodilator) can lower blood pressure. When taken together, there is an increased risk of hypotension, especially when standing up quickly. The nurse should monitor the client for symptoms of low blood pressure such as dizziness, fainting, or lightheadedness. D. Hyperglycemia: Atenolol may mask signs of hypoglycemia in clients with diabetes, but it does not directly cause hyperglycemia. Nitroglycerin is not typically associated with hyperglycemia either. Therefore, hyperglycemia is not a concern in this scenario.