The nurse is administering an estrogen blocker to a client diagnosed with advanced breast cancer. Which of the following side effects will the nurse caution the client regarding?

A. Tendon rupture: Tendon rupture is not a side effect associated with estrogen blockers. B. Phlebitis: While thromboembolic events are a risk, phlebitis (inflammation of a vein) is not a typical concern. C. Increased risk of lymphomas: Estrogen blockers are not known to increase the risk of lymphomas. D. Thromboembolic events: Estrogen blockers, such as tamoxifen, are associated with an increased risk of thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism).