What is the primary reason a nurse would monitor a client for epistaxis while administering reteplase?

Monitoring a client for epistaxis while administering reteplase is primarily focused on watching for bleeding complications. Reteplase is a thrombolytic agent used to dissolve blood clots, commonly in the treatment of acute myocardial infarction. Its mechanism of action involves breaking down fibrin within a clot, which can increase the likelihood of bleeding from various sites in the body, including the nose.

Epistaxis, or nosebleeds, is one of the many potential bleeding complications that can arise due to the use of a medication that affects clotting. By keeping an eye out for signs of bleeding, the nurse can promptly address any complications that arise, ensuring the client's safety and managing any adverse effects of the treatment.

The other choices, including monitoring for allergic reactions, assessing for gastrointestinal upset, or evaluating the medication's effectiveness, are important considerations in a clinical setting but do not address the specific bleeding risks associated with the use of thrombolytic therapy like reteplase. Such complications are a priority, given the nature of the drug and its intended effects.